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QSK Operation (full Break-in)
In CW Morse code operations, QSK or full break-in operation describes an operating mode in which the transmitting station can detect signals from other stations between the elements (dots and dashes) or letters of the Morse transmission. This allows other stations to interrupt the transmitting station between individual coding elements, and such allows for a conversational style of communication. "QSK" is one of the Q-code signals established for radiotelegraph operators in the first decade of the 1900s. The three letter code "QSK" literally means "''I can hear you between my signals; you may break in on my transmission.''" Although Morse code is no longer used for commercial or professional purposes, it continues to be used in amateur radio. In ''QSK'' or ''full break-in'' operation the silent periods between the Morse code dits and dahs enable operators to listen between their transmitted signals for the signals of the counterpart, thus enabling a conversational style of com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continuous Wave
A continuous wave or continuous waveform (CW) is an electromagnetic wave of constant amplitude and frequency, typically a sine wave, that for mathematical analysis is considered to be of infinite duration. It may refer to e.g. a laser or particle accelerator having a continuous output, as opposed to a pulsed output. Continuous wave is also the name given to an early method of radio transmission, in which a sinusoidal carrier wave is switched on and off. Information is carried in the varying duration of the on and off periods of the signal, for example by Morse code in early radio. In early wireless telegraphy radio transmission, CW waves were also known as "undamped waves", to distinguish this method from damped wave signals produced by earlier ''spark gap'' type transmitters. Radio Transmissions before CW Very early radio transmitters used a spark gap to produce radio-frequency oscillations in the transmitting antenna. The signals produced by these spark-gap transmitters c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Channel
A communication channel refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel in telecommunications and computer networking. A channel is used for information transfer of, for example, a digital bit stream, from one or several ''senders'' to one or several '' receivers''. A channel has a certain capacity for transmitting information, often measured by its bandwidth in Hz or its data rate in bits per second. Communicating an information signal across distance requires some form of pathway or medium. These pathways, called communication channels, use two types of media: Transmission line (e.g. twisted-pair, coaxial, and fiber-optic cable) and broadcast (e.g. microwave, satellite, radio, and infrared). In information theory, a channel refers to a theoretical ''channel model'' with certain error characteristics. In this more general view, a storage device is also a communication channel, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relay
A relay Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts An automotive-style miniature relay with the dust cover taken off A relay is an electrically operated switch. It consists of a set of input terminals for a single or multiple control signals, and a set of operating contact terminals. The switch may have any number of contacts in multiple contact forms, such as make contacts, break contacts, or combinations thereof. Relays are used where it is necessary to control a circuit by an independent low-power signal, or where several circuits must be controlled by one signal. Relays were first used in long-distance telegraph circuits as signal repeaters: they refresh the signal coming in from one circuit by transmitting it on another circuit. Relays were used extensively in telephone exchanges and early computers to perform logical operations. The traditional form of a relay uses an electromagnet to c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Automatic Gain Control
Automatic gain control (AGC) is a closed-loop feedback regulating circuit in an amplifier or chain of amplifiers, the purpose of which is to maintain a suitable signal amplitude at its output, despite variation of the signal amplitude at the input. The average or peak output signal level is used to dynamically adjust the gain of the amplifiers, enabling the circuit to work satisfactorily with a greater range of input signal levels. It is used in most radio receivers to equalize the average volume (loudness) of different radio stations due to differences in received signal strength, as well as variations in a single station's radio signal due to fading. Without AGC the sound emitted from an AM radio receiver would vary to an extreme extent from a weak to a strong signal; the AGC effectively reduces the volume if the signal is strong and raises it when it is weaker. In a typical receiver the AGC feedback control signal is usually taken from the detector stage and applied to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog Front-end
An analog front-end (AFE or analog front-end controller AFEC) is a set of analog signal conditioning circuitry that uses sensitive analog amplifiers, often operational amplifiers, filters, and sometimes application-specific integrated circuits for sensors, radio receivers, and other circuits to provide a configurable and flexible electronics functional block needed to interface a variety of sensors to an antenna, analog-to-digital converter or, in some cases, to a microcontroller. A radio frequency AFE is used in radio receivers, known as an RF front end. Modules AFE hardware modules are used as interface sensors for many kinds of analog and digital systems, providing hardware modularity. For example, Texas Instruments markets health monitoring AFEs as the ADS1298, AFE4400 and AFE4490. Atmel markets analog front-ends for smart meters. Analog Devices markets a CN0209 product for test and measurement applications. References {{Reflist Analog circuits Electronic circuits ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telegraphists
Telegraphists Football Club was a 19th-century association football club based at Govan, now in Glasgow. History The club was founded in 1874 for workers at the Telegraph Department of the Glasgow General Post Office, as a winter activity for cricket club members; the Telegraphists cricket club used the same venue for its home matches, and cricket captain Atkinson was one of the club's forwards. In 1876 and 1877 the club had 43 members. The media occasionally referred to the club as Telegraphers but its title as reported to the Scottish Football Association was Telegraphists. The club entered the Scottish Cup for the first time in 1875–76, losing 3–0 to the St Andrew's (Glasgow) club on Glasgow Green Glasgow Green is a park in the east end of Glasgow, Scotland, on the north bank of the River Clyde. Established in the 15th century, it is the oldest park in the city. It connects to the south via the St Andrew's Suspension Bridge. History I ...; all three goals c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Protocol
A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchronization of communication and possible error recovery methods. Protocols may be implemented by hardware, software, or a combination of both. Communicating systems use well-defined formats for exchanging various messages. Each message has an exact meaning intended to elicit a response from a range of possible responses pre-determined for that particular situation. The specified behavior is typically independent of how it is to be implemented. Communication protocols have to be agreed upon by the parties involved. To reach an agreement, a protocol may be developed into a technical standard. A programming language describes the same for computations, so there is a close analogy between protocols and programming languages: ''protocols ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prosigns For Morse Code
Procedural signs or prosigns are shorthand signals used in Morse code radio telegraphy procedure, for the purpose of simplifying and standardizing radio communication protocol. They are separate from Morse code abbreviations, which consist mainly of brevity codes that convey messages to other parties with greater speed and accuracy. In general prosigns are just standardised parts of short form radio protocol, and can include any abbreviation. An example would be K for "okay, heard you, continue". In a more limited role the term refers to something akin to that of the nonprinting control characters in teleprinter and computer character sets, such as Baudot or ASCII. Different from abbreviations, those are universally recognizable across language barriers as distinct and well-defined symbols. At the coding level, prosigns admit any form the Morse code can take, unlike abbreviations which have to follow letter form. Many of them are longer than typical characters and are rendered wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voice-operated Switch
In telecommunications, a voice operated switch, also known as VOX or voice-operated exchange, is a switch that operates when sound over a certain threshold is detected. It is usually used to turn on a transmitter or recorder when someone speaks and turn it off when they stop speaking. It is used instead of a push-to-talk button on transmitters or to save storage space on recording devices. On cell phones, it is used to save battery life. Intercom systems that use a speaker in a room as both a speaker and a microphone will often use VOX on the main console to switch the audio direction during a conversation. The circuit usually includes a delay between the sound stopping and switching direction, to avoid the circuit turning off during short pauses in speech. A special case exists, if there is enough energy to power the system directly. For example, a microphone may send a voltage high enough to directly operate a transmitter. Comparison with push-to-talk Unlike manual push-to-talk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duplex (telecommunications)
A duplex communication system is a point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many communications networks, either to allow for simultaneous communication in both directions between two connected parties or to provide a reverse path for the monitoring and remote adjustment of equipment in the field. There are two types of duplex communication systems: full-duplex (FDX) and half-duplex (HDX). In a full-duplex system, both parties can communicate with each other simultaneously. An example of a full-duplex device is plain old telephone service; the parties at both ends of a call can speak and be heard by the other party simultaneously. The earphone reproduces the speech of the remote party as the microphone transmits the speech of the local party. There is a two-way communication channel between them, or more strictly speaking, there are two communication channel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Protocol
A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchronization of communication and possible error recovery methods. Protocols may be implemented by hardware, software, or a combination of both. Communicating systems use well-defined formats for exchanging various messages. Each message has an exact meaning intended to elicit a response from a range of possible responses pre-determined for that particular situation. The specified behavior is typically independent of how it is to be implemented. Communication protocols have to be agreed upon by the parties involved. To reach an agreement, a protocol may be developed into a technical standard. A programming language describes the same for computations, so there is a close analogy between protocols and programming languages: ''protocols ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QST Magazine
''QST'' is a magazine for amateur radio enthusiasts, published by the American Radio Relay League (ARRL). It is a membership journal that is included with membership in the ARRL. The publisher claims that circulation of ''QST'' in the United States is higher than all other amateur radio-related publications in the United States combined. Although an exact number for circulation is not published by the American Radio Relay League, the organization claimed 158,238 members at the end of 2021, almost all of whom receive the magazine monthly, in addition to issues delivered to libraries and newsstands. Its first issue was dated December 1915. ''QST'' suspended publication after September 1917 due to World War I, but has been in continuous publication since it resumed in May 1919. Magazine name The magazine’s name is the radio "Q signal" for "calling all stations" or "the following message is to be forwarded to all amateur stations". Content ''QST'' incl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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