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Charles Evers

James Charles Evers (September 11, 1922 –July 22, 2020) was an American civil rights activist, businessman, radio personality, and politician. Evers was known for his role in the civil rights movement along with his younger brother Medgar Evers. After serving in World War II, Evers began his career as a disc jockey at WHOC in Philadelphia, Mississippi. In 1954, he was made the National Association for the Advancement of Colored People (NAACP) State Voter Registration chairman. After his brother's assassination in 1963, Evers took over his position as field director of the NAACP in Mississippi. In this role, he organized and led many demonstrations for the rights of African Americans.

In 1969, Evers was named "Man of the Year" by the NAACP. On June 3, 1969, he was elected in Fayette, Mississippi, as the first African-American mayor of a biracial town in Mississippi since the Reconstruction era, following passage of the Voting Rights Act of 1965 which enforced constitutional rights for citizens.

At the time of Evers' election as mayor, the town of Fayette had a population of 1,600 of which 75% was African-American and almost 25% white; the white officers on the Fayette city police "resigned rather than work under a black administration," according to the Associated Press. Evers told reporters, "I guess we will just have to operate with an all-black police department for the present. But I am still looking for some whites to join us in helping Fayette grow." Evers then outlawed the carrying of firearms within city limits.

Evers ran for governor in 1971 and the United States Senate in 1978, both times as an independent candidate. In 1989, he was defeated for re-election after serving sixteen years as mayor. In his later life, Evers became a Republican, endorsing Ronald Reagan in 1980, and more recently Donald Trump in 2016. This diversity in party affiliations throughout his life was reflected in his fostering of friendships with people from a variety of backgrounds, as well as his advising of politicians from across the political spectrum. After his political career ended, Evers returned to radio and hosted his own show, Let's Talk. In 2017, Evers was inducted into the National Rhythm & Blues Hall of Fame for his contributions to the music industry.

Early life and education
Charles Evers was born in Decatur, Mississippi, on September 11, 1922, to James Evers, a laborer, and Jesse Wright Evers, a maid. He was the eldest of four children; Medgar Evers was his younger brother. Evers attended segregated public schools, which were typically underfunded in Mississippi following the exclusion of African Americans from the political system by disenfranchisement after 1890. Evers graduated from Alcorn State University in Lorman, Mississippi.

Business activities
During World War II, Charles and Medgar Evers both served in the United States Army. Charles fell in love with a Philippine woman while stationed overseas. He could not marry her and bring her home to Mississippi because the state's constitution prohibited interracial marriages.

During the war, Evers established a brothel in Quezon City which catered to American servicemen. After serving a year of reserve duty following the Korean War, he settled in Philadelphia, Mississippi. In 1949, Evers began working as a disc jockey at WHOC, making him the first black disc jockey in the state. By the early 1950s, Evers was managing a hotel, cab company, and burial insurance business in the town. He had a cafe in Philadelphia and influenced over two hundred black citizens to pay their poll tax. Forced to leave due to local white hostility in 1956, Evers moved to Chicago. Low on money, he began working as a meatpacker in stockyards during the day and as an attendant for the men's restroom at the Conrad Hilton Hotel at nights. Evers also began pimping and ran a numbers game, taking $500 a week from the latter. He gained enough money to purchase several bars, bootlegged liquor, and sold jukeboxes.

Civil rights activism
In Mississippi about 1951, brothers Charles and Medgar Evers grew interested in African freedom movements. They were interested in Jomo Kenyatta and the rise of the Kikuyu tribal resistance to colonialism in Kenya, known as the Mau Mau uprising as it moved to open violence. Along with his brother, Charles became active in the Regional Council of Negro Leadership (RCNL), a civil rights organization that promoted self-help and business ownership. He also helped his brother with black voter registration drives. Between 1952 and 1955, Evers often spoke at the RCNL's annual conferences in Mound Bayou, a town founded by freedmen, on such issues as voting rights. His brother Medgar continued to be involved in civil rights, becoming field secretary and head of the National Association for the Advancement of Colored People (NAACP) in Mississippi. While working in Chicago he sent money to him, not specifying the source.

On June 12, 1963, Byron De La Beckwith, a member of a Ku Klux Klan chapter, fatally shot Evers' brother, Medgar, in Mississippi as he arrived home from work. Medgar died at the hospital in Jackson. Charles learned of his brother's death several hours later and flew to Jackson in the morning. Deeply upset by the assassination, Charles heavily involved himself in the planning of his brother's funeral. He decided to relocate to Mississippi to carry on his brother's work. Journalist Jason Berry, who later worked for Charles, said, "I think he wanted to be a better person. I think Medgar's death was a cathartic experience." A decade after his death, Evers and blues musician B.B. King created the Medgar Evers Homecoming Festival, an annual three-day event held the first week of June in Mississippi.

Over the opposition of more establishment figures in the National Association for the Advancement of Colored People (NAACP) such as Roy Wilkins, Evers took over his brother's post as head of the NAACP in Mississippi. Wilkins never managed a friendly relationship with Evers, and Medgar's widow, Myrlie, also disapproved of Charles' replacing him. A staunch believer in racial integration, Evers distrusted what he viewed as the militancy and separatism of the Student Nonviolent Coordinating Committee and the Mississippi Freedom Democratic Party, a black-dominated breakaway of the segregationist Mississippi Democratic Party. In 1965, Evers launched a series of successful black boycotts in southwestern Mississippi which partnered with the Natchez Deacons for Defense and Justice, which won concessions from the Natchez authorities and ratified his unconventional boycott methods. Often accompanied by a group of 65 male followers, he would pressure local blacks in small towns to avoid stores under boycott and directly challenge white business leaders. Evers also led a voter registration campaign. He coordinated his efforts from the small town of Fayette in Jefferson County. Fayette was a small, economically depressed town of about 2,500 people. About three-fourths of the population was black, and they had long been socially and economically subordinate to the white minority. Evers moved the NAACP's Mississippi field office from Jackson to Fayette to take advantage of the potential of the black majority and achieve political influence in Jefferson and two adjacent counties. He explained, "My feeling is that Negroes gotta control somewhere in America, and we've dropped anchor in these counties. We are going to control these three counties in the next ten years. There is no question about it."

With his voter registration drives having made Fayette's number of black registered voters double the size of the white electorate, Evers helped elect a black man to the local school board in 1966. He also established the Medgar Evers Community Center at the outskirts of town, which served as a center for registration efforts, grocery store, restaurant, and dance hall. By early 1968, Evers had established a network of local NAACP branches in the region. The president of each branch served as Evers' deputies, and he attended all of their meetings. That same year, Evers made a bid for the open seat of the 3rd congressional district in the U.S. House of Representatives, facing six white opponents in the Democratic primary. Though low on funds, he led in the primary with a plurality of the votes. The Mississippi Legislature responded by passing a law mandating a runoff primary in the event of no absolute majority in the initial contest, which Evers lost. He also supported Robert F. Kennedy's 1968 presidential campaign, serving as co-director of his Mississippi campaign organization, and was with Kennedy in Los Angeles when he was assassinated.

Mayor of Fayette
In May 1969, Evers ran for the office of Mayor of Fayette and defeated white incumbent R. J. Allen, 386 votes to 255. This made him the first black mayor of a biracial Mississippi town (unlike the all-black Mound Bayou) since Reconstruction. Evers' election as mayor had great symbolic significance statewide and attracted national attention. The NAACP named him their 1969 Man of the Year. Evers popularized the slogan, "Hands that picked cotton can now pick the mayor." The local white community was bitter about his victory, but he became intensively popular among Mississippi's blacks. To celebrate his victory, Evers hosted an inaugural ball in Natchez, which was widely attended by black Mississippians, reporters from around the country, and prominent national liberals including Ramsey Clark, Ted Sorensen, Whitney Young, Julian Bond, Shirley MacLaine, and Paul O'Dwyer. The white-dominated school board refused to let Evers swear-in on property under their jurisdiction, so he took his oath of office in a parking lot.

Evers appointed a black police force and several black staff members. He also benefitted from an influx of young, white liberal volunteers who wanted to assist a civil rights leader. Many ended up leaving after growing disillusioned with Evers' pursuit of personal financial success and domineering leadership style. He sought to make Fayette an upstanding community and a symbolic refuge for black people. Repulsed by the behavior of poor blacks in the town, he ordered the police force to enforce a 25-mile per hour speed limit on local roads, banned cursing in public, and cracked down on truancy. Evers also prohibited the carrying of firearms in town but kept a gun on himself. He quickly responded to concerns from poor blacks while making white businessmen wait outside of his office. Rhetorically, Evers would vacillate between messages of racial conciliation and statements of hostility.

Fayette's white population remained bitter about Evers' victory. Many avoided the city hall where they used to socialize and The Fayette Chronicle regularly criticized him. He argued with the county board of supervisors over his plan to erect busts of his brother, Martin Luther King Jr., and the Kennedys on the courthouse square. Evers told the press, "They're cooperating because they haven't blown my head off. This is Mississippi." In September 1969, a Klansman drove into Fayette with a collection of weapons, intending to assassinate Evers. A white resident tipped off the mayor and the Klansman was arrested. The Klansman defended his motives by saying, "I am a Mississippi white man".

Evers' moralistic style began to create discontent; in early 1970, most of Fayette's police department resigned, saying the mayor had treated them "like dogs". He complained that local blacks were "jealous" of him. As the judge in the municipal court, Evers personally issued fines for infractions such as cursing in public. He regularly ignored the input of the town board of aldermen, and town employee Charles Ramberg reported that he said he would fire municipal workers who would not vote for him. During Evers' tenure, Fayette benefitted from several federal grants, and ITT Inc. built an assembly plant in the town, but the region's economy largely remained depressed. By 1981, Jefferson County had the highest unemployment rate in the state.

Whites' perception that Evers was venal and self-interested persisted and began to spread among the black community. This problem ballooned when in 1974 the Internal Revenue Service arranged for him to be indicted for tax evasion by failing to report $156,000 in income he garnered in the late 1960s. Prosecutors further accused Evers of depositing town funds in a personal bank account. His attorney told the court that Evers had indeed concealed the income, but argued that the charge was invalid since this had been done before the late 1960s, as the indictment specified. The case resulted in a mistrial, but Evers' reputation permanently suffered. In the late 1970s, he used a $5,300 federal grant to renovate a building Evers owned which he leased to a federal day care program, and used some of the employees for personal business.

Evers served many terms as mayor of Fayette. Admired by some, he alienated others with his inflexible stands on various issues. Evers did not like to share or delegate power. He lost the Democratic primary for mayor in 1981 to Kennie Middleton. Four years later, Evers defeated Middleton in the primaries and won back the office of mayor. In 1989, Evers lost the nomination once again to political rival Kennie Middleton. In his response to the defeat, Evers accepted, said he was tired, and that: "Twenty years is enough. I'm tired of being out front. Let someone else be out front."

1971 gubernatorial campaign
Evers began mulling the possibility of a campaign for the office of governor in 1969. He decided to enter the 1971 gubernatorial election as an independent, kicking off his campaign with a rally in Decatur. Evers later explained his reason for launching the bid, saying, "I ran for governor because if someone doesn't start running, there will never be a black man or a black woman governor of the state of Mississippi." He endorsed white segregationist Jimmy Swan in the Democratic primary, reasoning that if Swan won the nomination, moderate whites would be more inclined to vote for himself in the general election. Evers campaigned on a platform of reduced taxes—particularly for lower property taxes on the elderly, improved healthcare, and legalizing gambling along the Gulf Coast. Low on money, his candidacy was largely funded by the sale of campaign buttons and copies of his recently published autobiography. Evers' campaign staff was largely young and inexperienced and lacked organization.

Evers' rallies drew large crowds of blacks. The Clarion-Ledger, a leading Mississippian conservative newspaper, largely ignored his campaign. To gain attention, he unexpectedly gatecrashed the annual Fisherman's Rodeo in Pascagoula and stopped and spoke to people on the streets of Jackson during their morning commute. Police departments in rural towns were often horrified by the arrival of his campaign caravan. A total of 269 other black candidates were running for office in Mississippi that year, and many of them complained that Evers was self-absorbed and hoarding resources, despite his slim chances of winning. Evers did little to support them.

In the general election, Evers faced Democratic nominee Bill Waller and independent segregationist Thomas Pickens Brady. Waller and Evers were personally acquainted with one another, as Waller had prosecuted Beckwith for the murder of Medgar. Despite the fears of public observers, the campaign was largely devoid of overt racist appeals and Evers and Waller avoided negative tactics. Though about 40 percent of the Mississippi electorate in 1971 was black, Evers only secured about 22 percent of the total vote; Waller won with 601,222 votes to Evers' 172,762 and Brady's 6,653. The night of the election, Evers shook the hands of Waller supporters in Jackson and then went to a local television station where his opponent was delivering a victory speech. Learning that Evers had arrived, Waller's nervous aides hurried the governor-elect to his car. Evers approached the car shortly before its departure and told Waller, "I just wanted to congratulate you." Waller replied, "Whaddya say, Charlie?" and his wife leaned over and shook Evers' hand.

Later political career
In 1978, Evers ran as an independent for the U.S. Senate seat vacated by Democrat James Eastland. He finished in third place behind his opponents, Democrat Maurice Dantin and Republican Thad Cochran. Evers received 24 percent of the vote, likely siphoning off African-American votes that would have otherwise gone to Dantin. Cochran won the election with a plurality of 45 percent of the vote. With the shift in white voters moving into the Republican Party in the state (and the rest of the South), Cochran was continuously re-elected to his Senate seat. After his failed Senate race, Evers briefly switched political parties and became a Republican.

In 1983, Evers ran as an independent for governor of Mississippi but lost to the Democrat Bill Allain. Republican Leon Bramlett of Clarksdale, also known as a college All-American football player, finished second with 39 percent of the vote.

Evers endorsed Ronald Reagan for President of the United States during the 1980 United States presidential election. Evers later attracted controversy for his support of judicial nominee Charles W. Pickering, a Republican, who was nominated by President George H. W. Bush for a seat on the U.S. Court of Appeals. Evers criticized the NAACP and other organizations for opposing Pickering, as he said the candidate had a record of supporting the civil rights movement in Mississippi.

Evers befriended a range of people from sharecroppers to presidents. He was an informal adviser to politicians as diverse as Lyndon B. Johnson, George C. Wallace, Ronald Reagan and Robert F. Kennedy. Evers severely criticized such national leaders as Roy Wilkins, Stokely Carmichael, H. Rap Brown and Louis Farrakhan over various issues.

Evers was a member of the Republican Party for 30 years when he spoke warmly of the 2008 election of Barack Obama as the first black President of the United States. During the 2016 presidential election, Evers supported Donald Trump's presidential campaign.

Books
Evers wrote two autobiographies or memoirs: Evers (1971), written with Grace Halsell and self-published; and Have No Fear, written with Andrew Szanton and published by John Wiley & Sons (1997).

Personal life
Evers was briefly married to Christine Evers until their marriage ended in annulment. In 1951, Evers married Nannie L. Magee, with whom he had four daughters. They divorced in June 1974. Evers lived in Brandon, Mississippi, and served as station manager of WMPR 90.1 FM in Jackson.

On July 22, 2020, Evers died in Brandon at age 97.

Media portrayal
Evers was portrayed by Bill Cobbs in the 1996 film Ghosts of Mississippi (1996).

Honors

 * 1969: Evers was named "Man of the Year" by the NAACP.
 * 2012: Evers was honored with a marker on the Mississippi Blues Trail in Fayette.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Charles Evers


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Code-division multiple access

Code-division multiple access (CDMA) is a channel access method used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communication channel. This allows several users to share a band of frequencies (see bandwidth). To permit this without undue interference between the users, CDMA employs spread spectrum technology and a special coding scheme (where each transmitter is assigned a code).

CDMA optimizes the use of available bandwidth as it transmits over the entire frequency range and does not limit the user's frequency range.

It is used as the access method in many mobile phone standards. IS-95, also called "cdmaOne", and its 3G evolution CDMA2000, are often simply referred to as "CDMA", but UMTS, the 3G standard used by GSM carriers, also uses "wideband CDMA", or W-CDMA, as well as TD-CDMA and TD-SCDMA, as its radio technologies. Many carriers (such as AT&T and Verizon) shut down 3G CDMA-based networks in 2022, rendering handsets supporting only those protocols unusable for calls, even to 911.

It can be also used as a channel or medium access technology, like ALOHA for example or as a permanent pilot/signalling channel to allow users to synchronize their local oscillators to a common system frequency, thereby also estimating the channel parameters permanently.

In these schemes, the message is modulated on a longer spreading sequence, consisting of several chips (0es and 1es). Due to their very advantageous auto- and crosscorrelation characteristics, these spreading sequences have also been used for radar applications for many decades, where they are called Barker codes (with a very short sequence length of typically 8 to 32).

For space-based communication applications, CDMA has been used for many decades due to the large path loss and Doppler shift caused by satellite motion. CDMA is often used with binary phase-shift keying (BPSK) in its simplest form, but can be combined with any modulation scheme like (in advanced cases) quadrature amplitude modulation (QAM) or orthogonal frequency-division multiplexing (OFDM), which typically makes it very robust and efficient (and equipping them with accurate ranging capabilities, which is difficult without CDMA). Other schemes use subcarriers based on binary offset carrier modulation (BOC modulation), which is inspired by Manchester codes and enable a larger gap between the virtual center frequency and the subcarriers, which is not the case for OFDM subcarriers.

History
The technology of code-division multiple access channels has long been known.

United States
In the US, one of the earliest descriptions of CDMA can be found in the summary report of Project Hartwell on "The Security of Overseas Transport", which was a summer research project carried out at the Massachusetts Institute of Technology from June to August 1950. Further research in the context of jamming and anti-jamming was carried out in 1952 at Lincoln Lab.

Soviet Union
In the Soviet Union (USSR), the first work devoted to this subject was published in 1935 by Dmitry Ageev. It was shown that through the use of linear methods, there are three types of signal separation: frequency, time and compensatory. The technology of CDMA was used in 1957, when the young military radio engineer Leonid Kupriyanovich in Moscow made an experimental model of a wearable automatic mobile phone, called LK-1 by him, with a base station. LK-1 has a weight of 3 kg, 20–30 km operating distance, and 20–30 hours of battery life. The base station, as described by the author, could serve several customers. In 1958, Kupriyanovich made the new experimental "pocket" model of mobile phone. This phone weighed 0.5 kg. To serve more customers, Kupriyanovich proposed the device, which he called "correlator." In 1958, the USSR also started the development of the "Altai" national civil mobile phone service for cars, based on the Soviet MRT-1327 standard. The phone system weighed 11 kg. It was placed in the trunk of the vehicles of high-ranking officials and used a standard handset in the passenger compartment. The main developers of the Altai system were VNIIS (Voronezh Science Research Institute of Communications) and GSPI (State Specialized Project Institute). In 1963 this service started in Moscow, and in 1970 Altai service was used in 30 USSR cities.

Uses

 * Synchronous CDM (code-division 'multiplexing', an early generation of CDMA) was implemented in the Global Positioning System (GPS). This predates and is distinct from its use in mobile phones.
 * The Qualcomm standard IS-95, marketed as cdmaOne.
 * The Qualcomm standard IS-2000, known as CDMA2000, is used by several mobile phone companies, including the Globalstar network.
 * The UMTS 3G mobile phone standard, which uses W-CDMA.
 * CDMA has been used in the OmniTRACS satellite system for transportation logistics.

Steps in CDMA modulation
CDMA is a spread-spectrum multiple-access technique. A spread-spectrum technique spreads the bandwidth of the data uniformly for the same transmitted power. A spreading code is a pseudo-random code in the time domain that has a narrow ambiguity function in the frequency domain, unlike other narrow pulse codes. In CDMA a locally generated code runs at a much higher rate than the data to be transmitted. Data for transmission is combined by bitwise XOR (exclusive OR) with the faster code. The figure shows how a spread-spectrum signal is generated. The data signal with pulse duration of $$T_b$$ (symbol period) is XORed with the code signal with pulse duration of $$T_c$$ (chip period). (Note: bandwidth is proportional to $$1/T$$, where $$T$$ = bit time.) Therefore, the bandwidth of the data signal is $$1/T_b$$ and the bandwidth of the spread spectrum signal is $$1/T_c$$. Since $$T_c$$ is much smaller than $$T_b$$, the bandwidth of the spread-spectrum signal is much larger than the bandwidth of the original signal. The ratio $$T_b/T_c$$ is called the spreading factor or processing gain and determines to a certain extent the upper limit of the total number of users supported simultaneously by a base station.

Each user in a CDMA system uses a different code to modulate their signal. Choosing the codes used to modulate the signal is very important in the performance of CDMA systems. The best performance occurs when there is good separation between the signal of a desired user and the signals of other users. The separation of the signals is made by correlating the received signal with the locally generated code of the desired user. If the signal matches the desired user's code, then the correlation function will be high and the system can extract that signal. If the desired user's code has nothing in common with the signal, the correlation should be as close to zero as possible (thus eliminating the signal); this is referred to as cross-correlation. If the code is correlated with the signal at any time offset other than zero, the correlation should be as close to zero as possible. This is referred to as auto-correlation and is used to reject multi-path interference.

An analogy to the problem of multiple access is a room (channel) in which people wish to talk to each other simultaneously. To avoid confusion, people could take turns speaking (time division), speak at different pitches (frequency division), or speak in different languages (code division). CDMA is analogous to the last example where people speaking the same language can understand each other, but other languages are perceived as noise and rejected. Similarly, in radio CDMA, each group of users is given a shared code. Many codes occupy the same channel, but only users associated with a particular code can communicate.

In general, CDMA belongs to two basic categories: synchronous (orthogonal codes) and asynchronous (pseudorandom codes).

Code-division multiplexing (synchronous CDMA)
The digital modulation method is analogous to those used in simple radio transceivers. In the analog case, a low-frequency data signal is time-multiplied with a high-frequency pure sine-wave carrier and transmitted. This is effectively a frequency convolution (Wiener–Khinchin theorem) of the two signals, resulting in a carrier with narrow sidebands. In the digital case, the sinusoidal carrier is replaced by Walsh functions. These are binary square waves that form a complete orthonormal set. The data signal is also binary and the time multiplication is achieved with a simple XOR function. This is usually a Gilbert cell mixer in the circuitry.

Synchronous CDMA exploits mathematical properties of orthogonality between vectors representing the data strings. For example, the binary string 1011 is represented by the vector (1, 0, 1, 1). Vectors can be multiplied by taking their dot product, by summing the products of their respective components (for example, if u = (a, b) and v = (c, d), then their dot product u·v = ac + bd). If the dot product is zero, the two vectors are said to be orthogonal to each other. Some properties of the dot product aid understanding of how W-CDMA works. If vectors a and b are orthogonal, then $$\mathbf{a}\cdot\mathbf{b} = 0$$ and:

\mathbf{a}\cdot(\mathbf{a} + \mathbf{b}) = \|\mathbf{a}\|^2,\ \text{since}\ \mathbf{a}\cdot\mathbf{a} + \mathbf{a}\cdot\mathbf{b} = \|\mathbf{a}\|^2 + 0, $$

\mathbf{a}\cdot(-\mathbf{a} + \mathbf{b}) = -\|\mathbf{a}\|^2,\ \text{since}\ {-\mathbf{a}}\cdot\mathbf{a} + \mathbf{a}\cdot\mathbf{b} = -\|\mathbf{a}\|^2 + 0, $$

\mathbf{b}\cdot(\mathbf{a} + \mathbf{b}) = \|\mathbf{b}\|^2,\ \text{since}\ \mathbf{b}\cdot\mathbf{a} + \mathbf{b}\cdot\mathbf{b} = 0 + \|\mathbf{b}\|^2, $$

\mathbf{b}\cdot(\mathbf{a} - \mathbf{b}) = -\|\mathbf{b}\|^2,\ \text{since}\ \mathbf{b}\cdot\mathbf{a} - \mathbf{b}\cdot\mathbf{b} = 0 - \|\mathbf{b}\|^2. $$

Each user in synchronous CDMA uses a code orthogonal to the others' codes to modulate their signal. An example of 4 mutually orthogonal digital signals is shown in the figure below. Orthogonal codes have a cross-correlation equal to zero; in other words, they do not interfere with each other. In the case of IS-95, 64-bit Walsh codes are used to encode the signal to separate different users. Since each of the 64 Walsh codes is orthogonal to all other, the signals are channelized into 64 orthogonal signals. The following example demonstrates how each user's signal can be encoded and decoded.

Example

Start with a set of vectors that are mutually orthogonal. (Although mutual orthogonality is the only condition, these vectors are usually constructed for ease of decoding, for example columns or rows from Walsh matrices.) An example of orthogonal functions is shown in the adjacent picture. These vectors will be assigned to individual users and are called the code, chip code, or chipping code. In the interest of brevity, the rest of this example uses codes v with only two bits.

Each user is associated with a different code, say v. A 1 bit is represented by transmitting a positive code v, and a 0 bit is represented by a negative code −v. For example, if v = (v0, v1) = (1, −1) and the data that the user wishes to transmit is (1, 0, 1, 1), then the transmitted symbols would be
 * (v, −v, v, v) = (v0, v1, −v0, −v1, v0, v1, v0, v1) = (1, −1, −1, 1, 1, −1, 1, −1).

For the purposes of this article, we call this constructed vector the transmitted vector.

Each sender has a different, unique vector v chosen from that set, but the construction method of the transmitted vector is identical.

Now, due to physical properties of interference, if two signals at a point are in phase, they add to give twice the amplitude of each signal, but if they are out of phase, they subtract and give a signal that is the difference of the amplitudes. Digitally, this behaviour can be modelled by the addition of the transmission vectors, component by component.

If sender0 has code (1, −1) and data (1, 0, 1, 1), and sender1 has code (1, 1) and data (0, 0, 1, 1), and both senders transmit simultaneously, then this table describes the coding steps:

Because signal0 and signal1 are transmitted at the same time into the air, they add to produce the raw signal

 * (1, −1, −1, 1, 1, −1, 1, −1) + (−1, −1, −1, −1, 1, 1, 1, 1) = (0, −2, −2, 0, 2, 0, 2, 0).

This raw signal is called an interference pattern. The receiver then extracts an intelligible signal for any known sender by combining the sender's code with the interference pattern. The following table explains how this works and shows that the signals do not interfere with one another:

Further, after decoding, all values greater than 0 are interpreted as 1, while all values less than zero are interpreted as 0. For example, after decoding, data0 is (2, −2, 2, 2), but the receiver interprets this as (1, 0, 1, 1). Values of exactly 0 mean that the sender did not transmit any data, as in the following example:

Assume signal0 = (1, −1, −1, 1, 1, −1, 1, −1) is transmitted alone. The following table shows the decode at the receiver:

When the receiver attempts to decode the signal using sender1's code, the data is all zeros; therefore the cross-correlation is equal to zero and it is clear that sender1 did not transmit any data.

Asynchronous CDMA
When mobile-to-base links cannot be precisely coordinated, particularly due to the mobility of the handsets, a different approach is required. Since it is not mathematically possible to create signature sequences that are both orthogonal for arbitrarily random starting points and which make full use of the code space, unique "pseudo-random" or "pseudo-noise" sequences called spreading sequences are used in asynchronous CDMA systems. A spreading sequence is a binary sequence that appears random but can be reproduced in a deterministic manner by intended receivers. These spreading sequences are used to encode and decode a user's signal in asynchronous CDMA in the same manner as the orthogonal codes in synchronous CDMA (shown in the example above). These spreading sequences are statistically uncorrelated, and the sum of a large number of spreading sequences results in multiple access interference (MAI) that is approximated by a Gaussian noise process (following the central limit theorem in statistics). Gold codes are an example of a spreading sequence suitable for this purpose, as there is low correlation between the codes. If all of the users are received with the same power level, then the variance (e.g., the noise power) of the MAI increases in direct proportion to the number of users. In other words, unlike synchronous CDMA, the signals of other users will appear as noise to the signal of interest and interfere slightly with the desired signal in proportion to number of users.

All forms of CDMA use the spread-spectrum spreading factor to allow receivers to partially discriminate against unwanted signals. Signals encoded with the specified spreading sequences are received, while signals with different sequences (or the same sequences but different timing offsets) appear as wideband noise reduced by the spreading factor.

Since each user generates MAI, controlling the signal strength is an important issue with CDMA transmitters. A CDM (synchronous CDMA), TDMA, or FDMA receiver can in theory completely reject arbitrarily strong signals using different codes, time slots or frequency channels due to the orthogonality of these systems. This is not true for asynchronous CDMA; rejection of unwanted signals is only partial. If any or all of the unwanted signals are much stronger than the desired signal, they will overwhelm it. This leads to a general requirement in any asynchronous CDMA system to approximately match the various signal power levels as seen at the receiver. In CDMA cellular, the base station uses a fast closed-loop power-control scheme to tightly control each mobile's transmit power.

In 2019, schemes to precisely estimate the required length of the codes in dependence of Doppler and delay characteristics have been developed. Soon after, machine learning based techniques that generate sequences of a desired length and spreading properties have been published as well. These are highly competitive with the classic Gold and Welch sequences. These are not generated by linear-feedback-shift-registers, but have to be stored in lookup tables.

Efficient practical utilization of the fixed frequency spectrum
In theory CDMA, TDMA and FDMA have exactly the same spectral efficiency, but, in practice, each has its own challenges – power control in the case of CDMA, timing in the case of TDMA, and frequency generation/filtering in the case of FDMA.

TDMA systems must carefully synchronize the transmission times of all the users to ensure that they are received in the correct time slot and do not cause interference. Since this cannot be perfectly controlled in a mobile environment, each time slot must have a guard time, which reduces the probability that users will interfere, but decreases the spectral efficiency.

Similarly, FDMA systems must use a guard band between adjacent channels, due to the unpredictable Doppler shift of the signal spectrum because of user mobility. The guard bands will reduce the probability that adjacent channels will interfere, but decrease the utilization of the spectrum.

Flexible allocation of resources
Asynchronous CDMA offers a key advantage in the flexible allocation of resources i.e. allocation of spreading sequences to active users. In the case of CDM (synchronous CDMA), TDMA, and FDMA the number of simultaneous orthogonal codes, time slots, and frequency slots respectively are fixed, hence the capacity in terms of the number of simultaneous users is limited. There are a fixed number of orthogonal codes, time slots or frequency bands that can be allocated for CDM, TDMA, and FDMA systems, which remain underutilized due to the bursty nature of telephony and packetized data transmissions. There is no strict limit to the number of users that can be supported in an asynchronous CDMA system, only a practical limit governed by the desired bit error probability since the SIR (signal-to-interference ratio) varies inversely with the number of users. In a bursty traffic environment like mobile telephony, the advantage afforded by asynchronous CDMA is that the performance (bit error rate) is allowed to fluctuate randomly, with an average value determined by the number of users times the percentage of utilization. Suppose there are 2N users that only talk half of the time, then 2N users can be accommodated with the same average bit error probability as N users that talk all of the time. The key difference here is that the bit error probability for N users talking all of the time is constant, whereas it is a random quantity (with the same mean) for 2N users talking half of the time.

In other words, asynchronous CDMA is ideally suited to a mobile network where large numbers of transmitters each generate a relatively small amount of traffic at irregular intervals. CDM (synchronous CDMA), TDMA, and FDMA systems cannot recover the underutilized resources inherent to bursty traffic due to the fixed number of orthogonal codes, time slots or frequency channels that can be assigned to individual transmitters. For instance, if there are N time slots in a TDMA system and 2N users that talk half of the time, then half of the time there will be more than N users needing to use more than N time slots. Furthermore, it would require significant overhead to continually allocate and deallocate the orthogonal-code, time-slot or frequency-channel resources. By comparison, asynchronous CDMA transmitters simply send when they have something to say and go off the air when they do not, keeping the same signature sequence as long as they are connected to the system.

Spread-spectrum characteristics of CDMA
Most modulation schemes try to minimize the bandwidth of this signal since bandwidth is a limited resource. However, spread-spectrum techniques use a transmission bandwidth that is several orders of magnitude greater than the minimum required signal bandwidth. One of the initial reasons for doing this was military applications including guidance and communication systems. These systems were designed using spread spectrum because of its security and resistance to jamming. Asynchronous CDMA has some level of privacy built in because the signal is spread using a pseudo-random code; this code makes the spread-spectrum signals appear random or have noise-like properties. A receiver cannot demodulate this transmission without knowledge of the pseudo-random sequence used to encode the data. CDMA is also resistant to jamming. A jamming signal only has a finite amount of power available to jam the signal. The jammer can either spread its energy over the entire bandwidth of the signal or jam only part of the entire signal. CDMA can also effectively reject narrow-band interference. Since narrow-band interference affects only a small portion of the spread-spectrum signal, it can easily be removed through notch filtering without much loss of information. Convolution encoding and interleaving can be used to assist in recovering this lost data. CDMA signals are also resistant to multipath fading. Since the spread-spectrum signal occupies a large bandwidth, only a small portion of this will undergo fading due to multipath at any given time. Like the narrow-band interference, this will result in only a small loss of data and can be overcome.

Another reason CDMA is resistant to multipath interference is because the delayed versions of the transmitted pseudo-random codes will have poor correlation with the original pseudo-random code, and will thus appear as another user, which is ignored at the receiver. In other words, as long as the multipath channel induces at least one chip of delay, the multipath signals will arrive at the receiver such that they are shifted in time by at least one chip from the intended signal. The correlation properties of the pseudo-random codes are such that this slight delay causes the multipath to appear uncorrelated with the intended signal, and it is thus ignored.

Some CDMA devices use a rake receiver, which exploits multipath delay components to improve the performance of the system. A rake receiver combines the information from several correlators, each one tuned to a different path delay, producing a stronger version of the signal than a simple receiver with a single correlation tuned to the path delay of the strongest signal.

Frequency reuse is the ability to reuse the same radio channel frequency at other cell sites within a cellular system. In the FDMA and TDMA systems, frequency planning is an important consideration. The frequencies used in different cells must be planned carefully to ensure signals from different cells do not interfere with each other. In a CDMA system, the same frequency can be used in every cell, because channelization is done using the pseudo-random codes. Reusing the same frequency in every cell eliminates the need for frequency planning in a CDMA system; however, planning of the different pseudo-random sequences must be done to ensure that the received signal from one cell does not correlate with the signal from a nearby cell.

Since adjacent cells use the same frequencies, CDMA systems have the ability to perform soft hand-offs. Soft hand-offs allow the mobile telephone to communicate simultaneously with two or more cells. The best signal quality is selected until the hand-off is complete. This is different from hard hand-offs utilized in other cellular systems. In a hard-hand-off situation, as the mobile telephone approaches a hand-off, signal strength may vary abruptly. In contrast, CDMA systems use the soft hand-off, which is undetectable and provides a more reliable and higher-quality signal.

Collaborative CDMA
A novel collaborative multi-user transmission and detection scheme called collaborative CDMA has been investigated for the uplink that exploits the differences between users' fading channel signatures to increase the user capacity well beyond the spreading length in the MAI-limited environment. The authors show that it is possible to achieve this increase at a low complexity and high bit error rate performance in flat fading channels, which is a major research challenge for overloaded CDMA systems. In this approach, instead of using one sequence per user as in conventional CDMA, the authors group a small number of users to share the same spreading sequence and enable group spreading and despreading operations. The new collaborative multi-user receiver consists of two stages: group multi-user detection (MUD) stage to suppress the MAI between the groups and a low-complexity maximum-likelihood detection stage to recover jointly the co-spread users' data using minimal Euclidean-distance measure and users' channel-gain coefficients. An enhanced CDMA version known as interleave-division multiple access (IDMA) uses the orthogonal interleaving as the only means of user separation in place of signature sequence used in CDMA system.

title: Code-division multiple access


text:
Internet filter

An Internet filter is software that restricts or controls the content an Internet user is capable to access, especially when utilized to restrict material delivered over the Internet via the Web, Email, or other means. Such restrictions can be applied at various levels: a government can attempt to apply them nationwide (see Internet censorship), or they can, for example, be applied by an Internet service provider to its clients, by an employer to its personnel, by a school to its students, by a library to its visitors, by a parent to a child's computer, or by an individual user to their own computers. The motive is often to prevent access to content which the computer's owner(s) or other authorities may consider objectionable. When imposed without the consent of the user, content control can be characterised as a form of internet censorship. Some filter software includes time control functions that empowers parents to set the amount of time that child may spend accessing the Internet or playing games or other computer activities.

Terminology
The term "content control" is used on occasion by CNN, Playboy magazine, the San Francisco Chronicle, and The New York Times. However, several other terms, including "content filtering software", "web content filter", "filtering proxy servers", "secure web gateways", "censorware", "content security and control", "web filtering software", "content-censoring software", and "content-blocking software", are often used. "Nannyware" has also been used in both product marketing and by the media. Industry research company Gartner uses "secure web gateway" (SWG) to describe the market segment.

Companies that make products that selectively block Web sites do not refer to these products as censorware, and prefer terms such as "Internet filter" or "URL Filter"; in the specialized case of software specifically designed to allow parents to monitor and restrict the access of their children, "parental control software" is also used. Some products log all sites that a user accesses and rates them based on content type for reporting to an "accountability partner" of the person's choosing, and the term accountability software is used. Internet filters, parental control software, and/or accountability software may also be combined into one product.

Those critical of such software, however, use the term "censorware" freely: consider the Censorware Project, for example. The use of the term "censorware" in editorials criticizing makers of such software is widespread and covers many different varieties and applications: Xeni Jardin used the term in a 9 March 2006 editorial in The New York Times, when discussing the use of American-made filtering software to suppress content in China; in the same month a high school student used the term to discuss the deployment of such software in his school district.

In general, outside of editorial pages as described above, traditional newspapers do not use the term "censorware" in their reporting, preferring instead to use less overtly controversial terms such as "content filter", "content control", or "web filtering"; The New York Times and The Wall Street Journal both appear to follow this practice. On the other hand, Web-based newspapers such as CNET use the term in both editorial and journalistic contexts, for example "Windows Live to Get Censorware."

Types of filtering
Filters can be implemented in many different ways: by software on a personal computer, via network infrastructure such as proxy servers, DNS servers, or firewalls that provide Internet access. No solution provides complete coverage, so most companies deploy a mix of technologies to achieve the proper content control in line with their policies.

 * Browser based filters
 * Browser based content filtering solution is the most lightweight solution to do the content filtering, and is implemented via a third party browser extension.

 * E-mail filters
 * E-mail filters act on information contained in the mail body, in the mail headers such as sender and subject, and e-mail attachments to classify, accept, or reject messages. Bayesian filters, a type of statistical filter, are commonly used. Both client and server based filters are available.

 * Client-side filters
 * This type of filter is installed as software on each computer where filtering is required. This filter can typically be managed, disabled or uninstalled by anyone who has administrator-level privileges on the system. A DNS-based client-side filter would be to set up a DNS Sinkhole, such as Pi-Hole.

 * Content-limited (or filtered) ISPs
 * Content-limited (or filtered) ISPs are Internet service providers that offer access to only a set portion of Internet content on an opt-in or a mandatory basis. Anyone who subscribes to this type of service is subject to restrictions. The type of filters can be used to implement government, regulatory or parental control over subscribers.

 * Network-based filtering
 * This type of filter is implemented at the transport layer as a transparent proxy, or at the application layer as a web proxy. Filtering software may include data loss prevention functionality to filter outbound as well as inbound information. All users are subject to the access policy defined by the institution. The filtering can be customized, so a school district's high school library can have a different filtering profile than the district's junior high school library.

 * DNS-based filtering
 * This type of filtering is implemented at the DNS layer and attempts to prevent lookups for domains that do not fit within a set of policies (either parental control or company rules). Multiple free public DNS services offer filtering options as part of their services. DNS Sinkholes such as Pi-Hole can be also be used for this purpose, though client-side only.

 * Search-engine filters
 * Many search engines, such as Google and Bing offer users the option of turning on a safety filter. When this safety filter is activated, it filters out the inappropriate links from all of the search results. If users know the actual URL of a website that features explicit or adult content, they have the ability to access that content without using a search engine. Some providers offer child-oriented versions of their engines that permit only child friendly websites.

Reasons for filtering
The Internet does not intrinsically provide content blocking, and therefore there is much content on the Internet that is considered unsuitable for children, given that much content is given certifications as suitable for adults only, e.g. 18-rated games and movies.

Internet service providers (ISPs) that block material containing pornography, or controversial religious, political, or news-related content en route are often utilized by parents who do not permit their children to access content not conforming to their personal beliefs. Content filtering software can, however, also be used to block malware and other content that is or contains hostile, intrusive, or annoying material including adware, spam, computer viruses, worms, trojan horses, and spyware.

Most content control software is marketed to organizations or parents. It is, however, also marketed on occasion to facilitate self-censorship, for example by people struggling with addictions to online pornography, gambling, chat rooms, etc. Self-censorship software may also be utilised by some in order to avoid viewing content they consider immoral, inappropriate, or simply distracting. A number of accountability software products are marketed as self-censorship or accountability software. These are often promoted by religious media and at religious gatherings.

Overblocking
Utilizing a filter that is overly zealous at filtering content, or mislabels content not intended to be censored can result in over blocking, or over-censoring. Over blocking can filter out material that should be acceptable under the filtering policy in effect, for example health related information may unintentionally be filtered along with porn-related material because of the Scunthorpe problem. Filter administrators may prefer to err on the side of caution by accepting over blocking to prevent any risk of access to sites that they determine to be undesirable. Content-control software was mentioned as blocking access to Beaver College before its name change to Arcadia University. Another example was the filtering of Horniman Museum. As well, over-blocking may encourage users to bypass the filter entirely.

Underblocking
Whenever new information is uploaded to the Internet, filters can under block, or under-censor, content if the parties responsible for maintaining the filters do not update them quickly and accurately, and a blacklisting rather than a whitelisting filtering policy is in place.

Morality and opinion
Many would not be satisfied with government filtering viewpoints on moral or political issues, agreeing that this could become support for propaganda. Many would also find it unacceptable that an ISP, whether by law or by the ISP's own choice, should deploy such software without allowing the users to disable the filtering for their own connections. In the United States, the First Amendment to the United States Constitution has been cited in calls to criminalise forced internet censorship. (See section below)

Legal actions
In 1998, a United States federal district court in Virginia ruled (Loudoun v. Board of Trustees of the Loudoun County Library) that the imposition of mandatory filtering in a public library violates the First Amendment.

In 1996 the US Congress passed the Communications Decency Act, banning indecency on the Internet. Civil liberties groups challenged the law under the First Amendment, and in 1997 the Supreme Court ruled in their favor. Part of the civil liberties argument, especially from groups like the Electronic Frontier Foundation, was that parents who wanted to block sites could use their own content-filtering software, making government involvement unnecessary.

In the late 1990s, groups such as the Censorware Project began reverse-engineering the content-control software and decrypting the blacklists to determine what kind of sites the software blocked. This led to legal action alleging violation of the "Cyber Patrol" license agreement. They discovered that such tools routinely blocked unobjectionable sites while also failing to block intended targets.

Some content-control software companies responded by claiming that their filtering criteria were backed by intensive manual checking. The companies' opponents argued, on the other hand, that performing the necessary checking would require resources greater than the companies possessed and that therefore their claims were not valid.

The Motion Picture Association successfully obtained a UK ruling enforcing ISPs to use content-control software to prevent copyright infringement by their subscribers.

Religious, anti-religious, and political censorship
Many types of content-control software have been shown to block sites based on the religious and political leanings of the company owners. Examples include blocking several religious sites (including the Web site of the Vatican), many political sites, and homosexuality-related sites. X-Stop was shown to block sites such as the Quaker web site, the National Journal of Sexual Orientation Law, The Heritage Foundation, and parts of The Ethical Spectacle. CYBERsitter blocks out sites like National Organization for Women. Nancy Willard, an academic researcher and attorney, pointed out that many U.S. public schools and libraries use the same filtering software that many Christian organizations use. Cyber Patrol, a product developed by The Anti-Defamation League and Mattel's The Learning Company, has been found to block not only political sites it deems to be engaging in 'hate speech' but also human rights web sites, such as Amnesty International's web page about Israel and gay-rights web sites, such as glaad.org.

Content labeling
Content labeling may be considered another form of content-control software. In 1994, the Internet Content Rating Association (ICRA) — now part of the Family Online Safety Institute — developed a content rating system for online content providers. Using an online questionnaire a webmaster describes the nature of their web content. A small file is generated that contains a condensed, computer readable digest of this description that can then be used by content filtering software to block or allow that site.

ICRA labels come in a variety of formats. These include the World Wide Web Consortium's Resource Description Framework (RDF) as well as Platform for Internet Content Selection (PICS) labels used by Microsoft's Internet Explorer Content Advisor.

ICRA labels are an example of self-labeling. Similarly, in 2006 the Association of Sites Advocating Child Protection (ASACP) initiated the Restricted to Adults self-labeling initiative. ASACP members were concerned that various forms of legislation being proposed in the United States were going to have the effect of forcing adult companies to label their content. The RTA label, unlike ICRA labels, does not require a webmaster to fill out a questionnaire or sign up to use. Like ICRA the RTA label is free. Both labels are recognized by a wide variety of content-control software.

The Voluntary Content Rating (VCR) system was devised by Solid Oak Software for their CYBERsitter filtering software, as an alternative to the PICS system, which some critics deemed too complex. It employs HTML metadata tags embedded within web page documents to specify the type of content contained in the document. Only two levels are specified, mature and adult, making the specification extremely simple.

Australia
The Australian Internet Safety Advisory Body has information about "practical advice on Internet safety, parental control and filters for the protection of children, students and families" that also includes public libraries.

NetAlert, the software made available free of charge by the Australian government, was allegedly cracked by a 16-year-old student, Tom Wood, less than a week after its release in August 2007. Wood supposedly bypassed the $84 million filter in about half an hour to highlight problems with the government's approach to Internet content filtering.

The Australian Government has introduced legislation that requires ISPs to "restrict access to age restricted content (commercial MA15+ content and R18+ content) either hosted in Australia or provided from Australia" that was due to commence from 20 January 2008, known as Cleanfeed.

Cleanfeed is a proposed mandatory ISP level content filtration system. It was proposed by the Beazley led Australian Labor Party opposition in a 2006 press release, with the intention of protecting children who were vulnerable due to claimed parental computer illiteracy. It was announced on 31 December 2007 as a policy to be implemented by the Rudd ALP government, and initial tests in Tasmania have produced a 2008 report. Cleanfeed is funded in the current budget, and is moving towards an Expression of Interest for live testing with ISPs in 2008. Public opposition and criticism have emerged, led by the EFA and gaining irregular mainstream media attention, with a majority of Australians reportedly "strongly against" its implementation. Criticisms include its expense, inaccuracy (it will be impossible to ensure only illegal sites are blocked) and the fact that it will be compulsory, which can be seen as an intrusion on free speech rights. Another major criticism point has been that although the filter is claimed to stop certain materials, the underground rings dealing in such materials will not be affected. The filter might also provide a false sense of security for parents, who might supervise children less while using the Internet, achieving the exact opposite effect. Cleanfeed is a responsibility of Senator Conroy's portfolio.

Denmark
In Denmark it is stated policy that it will "prevent inappropriate Internet sites from being accessed from children's libraries across Denmark". "'It is important that every library in the country has the opportunity to protect children against pornographic material when they are using library computers. It is a main priority for me as Culture Minister to make sure children can surf the net safely at libraries,' states Brian Mikkelsen in a press-release of the Danish Ministry of Culture."

United States
The use of Internet filters or content-control software varies widely in public libraries in the United States, since Internet use policies are established by the local library board. Many libraries adopted Internet filters after Congress conditioned the receipt of universal service discounts on the use of Internet filters through the Children's Internet Protection Act (CIPA). Other libraries do not install content control software, believing that acceptable use policies and educational efforts address the issue of children accessing age-inappropriate content while preserving adult users' right to freely access information. Some libraries use Internet filters on computers used by children only. Some libraries that employ content-control software allow the software to be deactivated on a case-by-case basis on application to a librarian; libraries that are subject to CIPA are required to have a policy that allows adults to request that the filter be disabled without having to explain the reason for their request.

Many legal scholars believe that a number of legal cases, in particular Reno v. American Civil Liberties Union, established that the use of content-control software in libraries is a violation of the First Amendment. The Children's Internet Protection Act [CIPA] and the June 2003 case United States v. American Library Association found CIPA constitutional as a condition placed on the receipt of federal funding, stating that First Amendment concerns were dispelled by the law's provision that allowed adult library users to have the filtering software disabled, without having to explain the reasons for their request. The plurality decision left open a future "as-applied" Constitutional challenge, however.

In November 2006, a lawsuit was filed against the North Central Regional Library District (NCRL) in Washington State for its policy of refusing to disable restrictions upon requests of adult patrons, but CIPA was not challenged in that matter. In May 2010, the Washington State Supreme Court provided an opinion after it was asked to certify a question referred by the United States District Court for the Eastern District of Washington: "Whether a public library, consistent with Article I, § 5 of the Washington Constitution, may filter Internet access for all patrons without disabling Web sites containing constitutionally-protected speech upon the request of an adult library patron." The Washington State Supreme Court ruled that NCRL's internet filtering policy did not violate Article I, Section 5 of the Washington State Constitution. The Court said: "It appears to us that NCRL's filtering policy is reasonable and accords with its mission and these policies and is viewpoint neutral. It appears that no article I, section 5 content-based violation exists in this case. NCRL's essential mission is to promote reading and lifelong learning. As NCRL maintains, it is reasonable to impose restrictions on Internet access in order to maintain an environment that is conducive to study and contemplative thought." The case returned to federal court.

In March 2007, Virginia passed a law similar to CIPA that requires public libraries receiving state funds to use content-control software. Like CIPA, the law requires libraries to disable filters for an adult library user when requested to do so by the user.

Bypassing filters
Content filtering in general can "be bypassed entirely by tech-savvy individuals." Blocking content on a device "[will not]…guarantee that users won't eventually be able to find a way around the filter." Content providers may change URLs or IP addresses to circumvent filtering. Individuals with technical expertise may use a different method by employing multiple domains or URLs that direct to a shared IP address where restricted content is present. This strategy doesn't circumvent IP packet filtering, however can evade DNS poisoning and web proxies. Additionally, perpetrators may use mirrored websites that avoid filters.

Some software may be bypassed successfully by using alternative protocols such as FTP or telnet or HTTPS, conducting searches in a different language, using a proxy server or a circumventor such as Psiphon. Also cached web pages returned by Google or other searches could bypass some controls as well. Web syndication services may provide alternate paths for content. Some of the more poorly designed programs can be shut down by killing their processes: for example, in Microsoft Windows through the Windows Task Manager, or in Mac OS X using Force Quit or Activity Monitor. Numerous workarounds and counters to workarounds from content-control software creators exist. Google services are often blocked by filters, but these may most often be bypassed by using https:// in place of http:// since content filtering software is not able to interpret content under secure connections (in this case SSL).

An encrypted VPN can be used as means of bypassing content control software, especially if the content control software is installed on an Internet gateway or firewall. Other ways to bypass a content control filter include translation sites and establishing a remote connection with an uncensored device.

Products and services
Some ISPs offer parental control options. Some offer security software which includes parental controls. Mac OS X v10.4 offers parental controls for several applications (Mail, Finder, iChat, Safari & Dictionary). Microsoft's Windows Vista operating system also includes content-control software.

Content filtering technology exists in two major forms: application gateway or packet inspection. For HTTP access the application gateway is called a web-proxy or just a proxy. Such web-proxies can inspect both the initial request and the returned web page using arbitrarily complex rules and will not return any part of the page to the requester until a decision is made. In addition they can make substitutions in whole or for any part of the returned result. Packet inspection filters do not initially interfere with the connection to the server but inspect the data in the connection as it goes past, at some point the filter may decide that the connection is to be filtered and it will then disconnect it by injecting a TCP-Reset or similar faked packet. The two techniques can be used together with the packet filter monitoring a link until it sees an HTTP connection starting to an IP address that has content that needs filtering. The packet filter then redirects the connection to the web-proxy which can perform detailed filtering on the website without having to pass through all unfiltered connections. This combination is quite popular because it can significantly reduce the cost of the system.

There are constraints to IP level packet-filtering, as it may result in rendering all web content associated with a particular IP address inaccessible. This may result in the unintentional blocking of legitimate sites that share the same IP address or domain. For instance, university websites commonly employ multiple domains under one IP address. Moreover, IP level packet-filtering can be surpassed by using a distinct IP address for certain content while still being linked to the same domain or server.

Gateway-based content control software may be more difficult to bypass than desktop software as the user does not have physical access to the filtering device. However, many of the techniques in the Bypassing filters section still work.

title: Internet filter


text:
Chambered cairn

A chambered cairn is a burial monument, usually constructed during the Neolithic, consisting of a sizeable (usually stone) chamber around and over which a cairn of stones was constructed. Some chambered cairns are also passage-graves. They are found throughout Britain and Ireland, with the largest number in Scotland.

Typically, the chamber is larger than a cist, and will contain a larger number of interments, which are either excarnated bones or inhumations (cremations). Most were situated near a settlement, and served as that community's "graveyard".

Background
During the early Neolithic (4000–3300 BC) architectural forms are highly regionalised with timber and earth monuments predominating in the east and stone-chambered cairns in the west. During the later Neolithic (3300–2500 BC) massive circular enclosures and the use of grooved ware and Unstan ware pottery emerge. Scotland has a particularly large number of chambered cairns; they are found in various different types described below. Along with the excavations of settlements such as Skara Brae, Links of Noltland, Barnhouse, Rinyo and Balfarg and the complex site at Ness of Brodgar these cairns provide important clues to the character of civilization in Scotland in the Neolithic. However the increasing use of cropmarks to identify Neolithic sites in lowland areas has tended to diminish the relative prominence of these cairns.

In the early phases bones of numerous bodies are often found together and it has been argued that this suggests that in death at least, the status of individuals was played down. During the late Neolithic henge sites were constructed and single burials began to become more commonplace; by the Bronze Age it is possible that even where chambered cairns were still being built they had become the burial places of prominent individuals rather than of communities as a whole.

Clyde-Carlingford court cairns
The Clyde or Clyde-Carlingford type are principally found in northern and western Ireland and southwestern Scotland. They first were identified as a separate group in the Firth of Clyde region, hence the name. Over 100 have been identified in Scotland alone. Lacking a significant passage, they are a form of gallery grave. The burial chamber is normally located at one end of a rectangular or trapezoidal cairn, while a roofless, semi-circular forecourt at the entrance provided access from the outside (although the entrance itself was often blocked), and gives this type of chambered cairn its alternate name of court tomb or court cairn. These forecourts are typically fronted by large stones and it is thought the area in front of the cairn was used for public rituals of some kind. The chambers were created from large stones set on end, roofed with large flat stones and often sub-divided by slabs into small compartments. They are generally considered to be the earliest in Scotland.

Examples include Cairn Holy I and Cairn Holy II near Newton Stewart, a cairn at Port Charlotte, Islay, which dates to 3900–4000 BC, and Monamore, or Meallach's Grave, Arran, which may date from the early fifth millennium BC. Excavations at the Mid Gleniron cairns near Cairnholy revealed a multi-period construction which shed light on the development of this class of chambered cairn.

Orkney-Cromarty
The Orkney-Cromarty group is by far the largest and most diverse. It has been subdivided into Yarrows, Camster and Cromarty subtypes but the differences are extremely subtle. The design is of dividing slabs at either side of a rectangular chamber, separating it into compartments or stalls. The number of these compartments ranges from 4 in the earliest examples to over 24 in an extreme example on Orkney. The actual shape of the cairn varies from simple circular designs to elaborate 'forecourts' protruding from each end, creating what look like small amphitheatres. It is likely that these are the result of cultural influences from mainland Europe, as they are similar to designs found in France and Spain.

Examples include Midhowe on Rousay, and both the Unstan Chambered Cairn and Wideford Hill chambered cairn from the Orkney Mainland, both of which date from the mid 4th millennium BC and were probably in use over long periods of time. When the latter was excavated in 1884, grave goods were found that gave their name to Unstan ware pottery. Blackhammer cairn on Rousay is another example dating from the 3rd millennium BC.

The Grey Cairns of Camster in Caithness are examples of this type from mainland Scotland. The Tomb of the Eagles on South Ronaldsay is a stalled cairn that shows some similarities with the later Maeshowe type. It was in use for 800 years or more and numerous bird bones were found here, predominantly white-tailed sea eagle.

Maeshowe
The Maeshowe group, named after the famous Orkney monument, is among the most elaborate. They appear relatively late and only in Orkney and it is not clear why the use of cairns continued in the north when their construction had largely ceased elsewhere in Scotland. They consist of a central chamber from which lead small compartments, into which burials would be placed. The central chambers are tall and steep-sided and have corbelled roofing faced with high quality stone. In addition to Maeshowe itself, which was constructed c. 2700 BC, there are various other examples from the Orkney Mainland. These include Quanterness chambered cairn (3250 BC) in which the remains of 157 individuals were found when excavated in the 1970s, Cuween Hill near Finstown which was found to contain the bones of men, dogs and oxen and Wideford Hill chambered cairn, which dates from 2000 BC.

Examples from elsewhere in Orkney are the Vinquoy chambered cairn, and the Huntersquoy chambered cairn, both found on the north end of the island of Eday and Quoyness on Sanday constructed about 2900 BC and which is surrounded by an arc of Bronze Age mounds. The central chamber of Holm of Papa Westray South cairn is over 20 metres long.

Bookan
The Bookan type is named after a cairn found to the north-west of the Ring of Brodgar in Orkney, which is now a dilapidated oval mound, about 16 metres in diameter. Excavations in 1861 indicated a rectangular central chamber surrounded by five smaller chambers. Because of the structure's unusual design, it was originally presumed to be an early form. However, later interpretations and further excavation work in 2002 suggested that they have more in common with the later Maeshowe type rather than the stalled Orkney-Cromarty cairns.

Huntersquoy chambered cairn on Eday is a double storied Orkney–Cromarty type cairn with a Booken-type lower chamber.

Shetland
The Shetland or Zetland group are relatively small passage graves, that are round or heel-shaped in outline. The whole chamber is cross or trefoil-shaped and there are no smaller individual compartments. An example is to be found on the uninhabited island of Vementry on the north side of the West Mainland, where it appears that the cairn may have originally been circular and its distinctive heel shape added as a secondary development, a process repeated elsewhere in Shetland. This probably served to make the cairn more distinctive and the forecourt area more defined.

Hebridean
Like the Shetland cairn the Hebridean group appear relatively late in the Neolithic. They are largely found in the Outer Hebrides, although a mixture of cairn types are found here. These passage graves are usually larger than the Shetland type and are round or have funnel-shaped forecourts, although a few are long cairns – perhaps originally circular but with later tails added. They often have a polygonal chamber and a short passage to one end of the cairn.

The Rubha an Dùnain peninsula on the island of  Skye provides an example from the 2nd or 3rd millennium BC. Barpa Langass on North Uist is the best preserved chambered cairn in the Hebrides.

Bargrennan
Bargrennan chambered cairns are a class of passage graves found only in south-west Scotland, in western Dumfries and Galloway and southern Ayrshire. As well as being structurally different from the nearby Clyde cairns, Bargrennan cairns are distinguished by their siting and distribution; they are found in upland, inland areas of Galloway and Ayrshire.

Bronze Age
In addition to the increasing prominence of individual burials, during the Bronze Age regional differences in architecture in Scotland became more pronounced. The Clava cairns date from this period, with about 50 cairns of this type in the Inverness area. Corrimony chambered cairn near Drumnadrochit is an example dated to 2000 BC or older. The only surviving evidence of burial was a stain indicating the presence of a single body. The cairn is surrounded by a circle of 11 standing stones. The cairns at Balnuaran of Clava are of a similar date. The largest of three is the north-east cairn, which was partially reconstructed in the 19th century and the central cairn may have been used as a funeral pyre.

Glebe cairn in Kilmartin Glen in Argyll dates from 1700 BC and has two stone cists inside one of which a jet necklace was found during 19th century excavations. There are numerous prehistoric sites in the vicinity including Nether Largie North cairn, which was entirely removed and rebuilt during excavations in 1930.

Chambered long cairns
There are 18 Scheduled Ancient Monuments listed:
 * Siambr gladdu Din Dryfol, Aberffraw
 * Carnedd gellog hir Pen y Wyrlod, Talgarth
 * Siambr gladdu Llety'r Filiast, Llandudno
 * Siambr gladdu Bachwen, Clynnog
 * Siambr gladdu Rhiw, Aberdaron
 * Siambr gladdu Maen y Bardd, Caerhun
 * Siambr gladdu Ystum-Cegid, Llanystumdwy
 * Siambr gladdu Caer-Dynni, Cricieth
 * Siambr gladdu Capel Garmon, Bro Garmon, Conwy
 * Siambr gladdu Tyddyn Bleiddyn, Cefn Meiriadog
 * Siambr gladdu Hendre-Waelod, Llansanffraid Glan Conwy
 * Parc Cwm long cairn, Parc le Breos, Gower Peninsula
 * Siambr gladdu Cefn Bryn, Llanilltud Gŵyr
 * Siambr gladdu Dyffryn, Dyffryn Ardudwy
 * Siambr gladdu Carneddau Hengwm, Dyffryn Ardudwy
 * Siambr gladdu Cors-y-Gedol, Dyffryn Ardudwy
 * Siambr gladdu Tan-y-Coed, Llandrillo
 * Siambr gladdu Gorllewin Bron-y-Foel, Dyffryn Ardudwy

Chambered round cairns

 * Siambr gladdu Bryn yr Hen Bobl, Llanddaniel Fab, Môn
 * Siambr gladdu Gelli, Llanfair-ar-y-bryn, Sir Gaerfyrddin
 * Siambr gladdu Cefnamwlch, Tudweiliog, Gwynedd
 * Siambr galddu Afon y Dolau Gwynion, overlooking Lake Vyrnwy, Llanwddyn, Powys

title: Chambered cairn


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Canadian whisky

Canadian whisky is a type of whisky produced in Canada. Most Canadian whiskies are blended multi-grain liquors containing a large percentage of corn spirits, and are typically lighter and smoother than other whisky styles. When Canadian distillers began adding small amounts of highly-flavourful rye grain to their mashes, people began demanding this new rye-flavoured whisky, referring to it simply as "rye". Today, as for the past two centuries, the terms "rye whisky" and "Canadian whisky" are used interchangeably in Canada and (as defined in Canadian law) refer to exactly the same product, which generally is made with only a small amount of rye grain.

Characteristics
Historically, in Canada, corn-based whisky that had some rye grain added to the mash bill to give it more flavour came to be called "rye".

The regulations under Canada's Food and Drugs Act stipulate the minimum conditions that must be met in order to label a product as "Canadian Whisky" or "Canadian Rye Whisky" (or "Rye Whisky")—these are also upheld internationally through geographical indication agreements. These regulations state that whisky must "be mashed, distilled and aged in Canada", "be aged in small wood vessels for not less than three years", "contain not less than 40 per cent alcohol by volume" and "may contain caramel and flavouring". Within these parameters Canadian whiskies can vary considerably, especially with the allowance of "flavouring"—though the additional requirement that they "possess the aroma, taste and character generally attributed to Canadian whisky" can act as a limiting factor.

Canadian whiskies are most typically blends of whiskies made from a single grain, principally corn and rye, but also sometimes wheat or barley. Mash bills of multiple grains may also be used for some flavouring whiskies. The availability of inexpensive American corn, with its higher proportion of usable starches relative to other cereal grains, has led it to be most typically used to create base whiskies to which flavouring whiskies are blended in. Exceptions to this include the Highwood Distillery which specializes in using wheat and the Alberta Distillers which developed its own proprietary yeast strain that specializes in distilling rye. The flavouring whiskies are most typically rye whiskies, blended into the product to add most of its flavour and aroma. While Canadian whisky may be labelled as a "rye whisky" this blending technique only necessitates a small percentage (such as 10%) of rye to create the flavour, whereas much more rye would be required if it were added to a mash bill alongside the more readily distilled corn.

The base whiskies are distilled to between 180 and 190 proof which results in few congener by-products (such as fusel alcohol, aldehydes, esters, etc.) and creates a lighter taste. By comparison, an American whisky distilled any higher than 160 proof is labelled as "light whiskey". The flavouring whiskies are distilled to a lower proof so that they retain more of the grain's flavour. The relative lightness created by the use of base whiskies makes Canadian whisky useful for mixing into cocktails and highballs. The minimum three year aging in small wood barrels applies to all whiskies used in the blend. As the regulations do not limit the specific type of wood that must be used, a variety of flavours can be achieved by blending whiskies aged in different types of barrels. In addition to new wood barrels, charred or uncharred, flavour can be added by aging whiskies in previously used bourbon or fortified wine barrels for different lengths of time.

History
In the 18th and early 19th centuries, gristmills distilled surplus grains to avoid spoilage. Most of these early whiskies would have been rough, mostly unaged wheat whiskey. Distilling methods and technologies were brought to Canada by American and European immigrants with experience in distilling wheat and rye. This early whisky from improvised stills, often with the grains closest to spoilage, was produced with various, uncontrolled proofs and was consumed, unaged, by the local market. While most distilling capacity was taken up producing rum, a result of Atlantic Canada's position in the British sugar trade, the first commercial scale production of whisky in Canada began in 1801 when John Molson purchased a copper pot still, previously used to produce rum, in Montreal. With his son Thomas Molson, and eventually partner James Morton, the Molsons operated a distillery in Montreal and Kingston and were the first in Canada to export whisky, benefiting from Napoleonic Wars' disruption in supplying French wine and brandies to England. Gooderham and Worts began producing whisky in 1837 in Toronto as a side business to their wheat milling but surpassed Molson's production by the 1850s as it expanded their operations with a new distillery in what would become the Distillery District. Henry Corby started distilling whisky as a side business from his gristmill in 1859 in what became known as Corbyville and Joseph Seagram began working in his father-in-law's Waterloo flour mill and distillery in 1864, which he would eventually purchase in 1883. Meanwhile, Americans Hiram Walker and J.P. Wiser moved to Canada: Walker to Windsor in 1858 to open a flour mill and distillery and Wiser to Prescott in 1857 to work at his uncle's distillery where he introduced a rye whisky and was successful enough to buy the distillery five years later. The disruption of American Civil War created an export opportunity for Canadian-made whiskies and their quality, particularly those from Walker and Wiser who had already begun the practice of aging their whiskies, sustained that market even after post-war tariffs were introduced. In the 1880s, Canada's National Policy placed high tariffs on foreign alcoholic products as whisky began to be sold in bottles and the federal government instituted a bottled in bond program that provided certification of the time a whisky spent aging and allowed deferral of taxes for that period, which encouraged aging. In 1890 Canada became the first country to enact an aging law for whiskies, requiring them to be aged at least two years. The growing temperance movement culminated in prohibition in 1916 and distilleries had to either specialize in the export market or switch to alternative products, like industrial alcohols which were in demand in support of the war effort. With the deferred revenue and storage costs of the Aging Law acting as a barrier to new entrants and the reduced market due to prohibition, consolidation of Canadian whisky had begun. Henry Corby Jr. modernized and expanded upon his father's distillery and sold it, in 1905, to businessman Mortimer Davis who also purchased the Wiser distillery, in 1918, from the heirs of J.P. Wiser. Davis's salesman Harry Hatch spent time promoting the Corby and Wiser brands and developing a distribution network in the United States which held together as Canadian prohibition ended and American prohibition began. After Hatch's falling out with Davis, Hatch purchased the struggling Gooderham and Worts in 1923 and switched out Davis's whisky for his. Hatch was successful enough to be able to also purchase the Walker distillery, and the popular Canadian Club brand, from Hiram's grandsons in 1926. While American prohibition created risk and instability in the Canadian whisky industry, some benefited from purchasing unused American distillation equipment and from sales to exporters (nominally to foreign countries like Saint Pierre and Miquelon, though actually to bootleggers to the United States). Along with Hatch, the Bronfman family was able to profit from making whisky destined for United States during prohibition, though mostly in Western Canada and were able to open a distillery in LaSalle, Quebec and merge their company, in 1928, with Seagram's which had struggled with transitioning to the prohibition marketplace. Samuel Bronfman became president of the company and, with his dominant personality, began a strategy of increasing their capacity and aging whiskies in anticipation of the end of prohibition. When that did occur, in 1933, Seagram's was in a position to quickly expand; they purchased The British Columbia Distilling Company from the Riefel family in 1935, as well as several American distilleries and introduced new brands, one of them being Crown Royal, in 1939, which would eventually become one of the best-selling Canadian whiskies.

While some capacity was switched to producing industrial alcohols in support of the country's World War II efforts, the industry expanded again after the war until the 1980s. In 1945, Schenley Industries purchased one of those industrial alcohol distilleries in Valleyfield, Quebec, and repurposed several defunct American whiskey brands, like Golden Wedding, Old Fine Copper, and starting in 1972, Gibson's Finest. Seeking to secure their supply of Canadian whisky, Barton Brands also built a new distillery in Collingwood, Ontario, in 1967, where they would produce Canadian Mist, though they sold the distillery and brand only four years later to Brown–Forman. As proximity to the shipping routes (by rail and boat) to the US became less important, large distilleries were established in Alberta and Manitoba. Five years after starting to experiment with whiskies in their Toronto gin distillery, W. & A. Gilbey Ltd. created the Black Velvet blend in 1951 which was so successful a new distillery in Lethbridge, Alberta was constructed in 1973 to produce it. Also in the west, a Calgary-based business group recruited the Riefels from British Columbia to oversee their Alberta Distillers operations in 1948. The company became an innovator in the practice of bulk shipping whiskies to the United States for bottling and the success of their Windsor Canadian brand (produced in Alberta but bottled in the United States) led National Distillers Limited to purchase Alberta Distillers, in 1964, to secure their supply chain. More Alberta investors founded the Highwood Distillery in 1974 in High River, Alberta, which specialized in wheat-based whiskies. Seagram's opened a large, new plant in Gimli, Manitoba, in 1969, which would eventually replace their Waterloo and LaSalle distilleries. In British Columbia, Ernie Potter who had been producing fruit liqueurs from alcohols distilled at Alberta Distillers built his own whisky distillery in Langley in 1958 and produced the Potter's and Century brands of whisky. Hiram Walker's built the Okanagan Distillery in Winfield, British Columbia, in 1970 with the intention of producing Canadian Club but was redirected to fulfill contracts to produce whiskies for Suntory before being closed in 1995.

After decades of expansion, a shift in consumer preferences towards white spirits (such as vodka) in the American market resulted in an excess supply of Canadian whiskies. While this allowed the whiskies to be aged longer, the unexpected storage costs and deferred revenue strained individual companies. With the distillers seeking investors and multinational corporations seeking value brands, a series of acquisitions and mergers occurred. Alberta Distillers was bought in 1987 by Fortune Brands which would go on to become part of Beam Suntory. Hiram Walker was sold in 1987 to Allied Lyons which Pernod Ricard took over in 2006, with Fortune Brands acquiring the Canadian Club brand. Grand Metropolitan had purchased Black Velvet in 1972 but sold the brand in 1999 to Constellation Brands who in turn sold it to Heaven Hill in 2019. Schenley was acquired in 1990 by United Distillers which would go on to become part of Diageo, though Gibson's Finest was sold to William Grant & Sons in 2001. Seagram's was sold in 2000 to Vivendi, which in turn sold its various brands and distilleries to Pernod Ricard and Diageo. Highwood would purchase Potter's in 2006. Despite the consolidation, the Kittling Ridge Distillery in Grimsby, Ontario, began to produce the Forty Creek brand, though it was sold to the Campari Group in 2014. Later, the Sazerac Company would purchase the brands Seagram's VO, Canadian 83 and Five Star from Diageo in 2018.

Illicit export to the United States
Canadian whisky featured prominently in rum-running into the U.S. during Prohibition. Hiram Walker's distillery in Windsor, Ontario, directly across the Detroit River and the international boundary between Canada and the United States, easily served bootleggers using small, fast smuggling boats.

Distilleries and brands
The following is a listing of distilleries presently producing Canadian whiskys:

Alberta
There are several distilleries based in Alberta, including the Alberta Distillers, established in 1946 in Calgary, Alberta. The distillery was purchased in 1987 by Fortune Brands which became Beam Suntory in 2011. The distillery uses a specific strain of yeast which they developed that specializes in fermenting rye. While the distillery exports much of its whisky for bottling in other countries, they also produce the brands Alberta Premium, Alberta Springs, Windsor Canadian, Tangle Ridge, and Canadian Club Chairman's Select.

Black Velvet Distillery (formerly the Palliser Distillery) was established in 1973 in Lethbridge, Alberta, and has been owned by Heaven Hill since 2019. It produces the Black Velvet brand, mostly shipped in bulk for bottling in America, with some bottled onsite for Canadians. It also makes Danfield's and the Schenley's Golden Wedding and OFC labels.

Highwood Distillery (formerly the Sunnyvale Distillery) was established in 1974 in High River, Alberta, the Highwood Distillery specializes in using wheat in their base whiskies. This distillery also produces vodka, rum, gin and liqueurs. Brands of Canadian whisky produced at the Highwood Distillery include Centennial, Century, Ninety, and Potter's. They also produce White Owl whisky which is charcoal-filtered to remove the colouring introduced by aging in wood barrels.

Manitoba
Gimli Distillery was established in 1968 in Gimli, Manitoba, to produce Seagram brands, the distillery was acquired by Diageo in 2001. The Gimli Distillery is responsible for producing Crown Royal, the best-selling Canadian whisky in the world with 7 million cases shipped in 2017. They also supply some of the whisky used in Seagram's VO and other blends.

Ontario
Distilleries were established in Ontario during the mid-19th century, with Gooderham and Worts's beginning operations in Toronto's Distillery District in the 1830s. Distilleries continued to operate from the Distillery District until 1990, when the area was reoriented towards commercial and residential development. Other former distilleries in the province includes one in Corbyville, which hosted a distillery operated by Corby Spirit and Wine. A distillery in Waterloo was operated by Seagram to produce Crown Royal until 1992; although the company still maintains a blending and bottling plant in Amherstburg. Presently, there are several major distilleries based in Ontario. The oldest functioning distillery in Ontario is the Hiram Walker Distillery, established in 1858 in Windsor, Ontario, but modernized and expanded upon several times since. The distillery is owned by Pernod Ricard and operated by Corby Spirit and Wine, of which Pernod has a controlling share. Brands produced at the Walker Distillery include Lot 40, Pike Creek, Gooderham and Worts, Hiram Walker's Special Old, Corby's Royal Reserve, and J.P. Wiser's brands. Most of its capacity is used for contract production of the Beam Suntory brand (and former Hiram Walker brand) Canadian Club, in addition to generic Canadian whisky that is exported in bulk and bottled under various labels in other countries.

Canadian Mist Distillery was established in 1967 in Collingwood, Ontario, the distillery is owned by the Sazerac Company and primarily produces the Canadian Mist brand for export. The distillery also produces whiskies used in the Collingwood brand, introduced 2011, and the Bearface brand, introduced 2018.

Kittling Ridge Distillery was established in 1992 with an associated winery in Grimsby, Ontario, its first whiskies came to market in 2002. The distillery was purchased in 2014 by Campari Group. The distillery produces the Forty Creek brand.

Quebec
Old Montreal Distillery was established in 1929 as a Corby Spirit and Wine distillery, it was acquired by Sazerac Company in 2011 and modernized in 2018. It produces Sazerac brands and has taken over bottling of Caribou Crossing.

Valleyfield Distillery (formerly the Schenley Distillery) was established in 1945 in a former brewery in Salaberry-de-Valleyfield, Quebec, near Montreal, the distillery has been owned by Diageo in 2008. Seagram's VO is bottled here with flavouring whisky from the Gimli Distillery. Otherwise, the Valleyfield Distillery specializes in producing base whiskies distilled from corn for other Diageo products.

title: Canadian whisky