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Noise Blanker
A Citizen's Band transceiver equipped with a noise blanker for the receiver, controlled by a button on the front panel (2nd from right) In the design of radio receivers, a noise blanker is a circuit intended to reduce the effect of certain kinds of radio noise on a received signal. It is often used on broadcast shortwave receivers or communications receivers and some types of two-way radio transceivers. The noise blanker is only effective on impulse-type noise such as from lightning or from automotive ignition systems, and cannot improve performance on wideband continuous background noise, or interfering signals on the same frequency. In cases where there are strong signals on frequencies near to the desired frequency, a noise blanker circuit may be ineffective and may reduce the quality of the received signal. Implementation Typically this is a network in the intermediate frequency section of the receiver; when a pulse of noise passes through the IF amplifiers, it is usua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CB Base Station
CB and variants may refer to: Places * CB postcode area, British post code for eastern England served by the Cambridge postal sorting office * Cambodia (FIPS Pub 10-4 country code and obsolete NATO digram CB) * Cape Breton (other) * Centura București, a ring road of Bucharest, Romania * Colegio Bolivar, an American school in Cali, Colombia * Colwyn Bay, Wales * Province of Campobasso, Italy * ČB – České Budějovice, Czech Republic People * Chris Bosh (born 1984), American basketball player * Henry Campbell-Bannerman (1836–1908), Prime Minister of the United Kingdom 1906–1908, widely referred to by his surname initials Brands and enterprises * Carte Bancaire, a bank card brand * Christianssands Bryggeri, a Norwegian brewery * ScotAirways (IATA airline code CB) Business and financial terms * Capacity building, the process by which individuals and organizations obtain, improve, and retain the skills and knowledge needed to undertake their tasks * Certific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Receiver Design
Radio receiver design includes the electronic design of different components of a radio receiver which processes the radio frequency signal from an antenna in order to produce usable information such as audio. The complexity of a modern receiver and the possible range of circuitry and methods employed are more generally covered in electronics and communications engineering. The term ''radio receiver'' is understood in this article to mean any device which is intended to receive a radio signal in order to generate useful information from the signal, most notably a recreation of the so-called baseband signal (such as audio) which modulated the radio signal at the time of transmission in a communications or broadcast system. Fundamental considerations Design of a radio receiver must consider several fundamental criteria to produce a practical result. The main criteria are gain, selectivity, sensitivity, and stability. The receiver must contain a detector to recover the information i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shortwave Receiver
A shortwave radio receiver is a radio receiver that can receive one or more shortwave bands, between 1.6 and 30 MHz. A shortwave radio receiver often receives other broadcast bands, such as FM radio, Longwave and Mediumwave. Shortwave radio receivers are often used by dedicated hobbyists called shortwave listeners. History While home built shortwave receivers had been used by amateur radio operators and radio experimenters prior to World War I, the first time shortwave radio reception was available to the general public was through the use of shortwave frequency converters sold as accessories to broadcast-band radio sets during the mid 1920s. Such converters were generally found unsatisfactory in performance, and so dedicated shortwave receiving sets soon appeared on the market. National Radio Company introduced the SW-2 "Thrill box" shortwave regenerative receiver in 1927, and later offered improved models, such as the highly regarded SW-3. Other notable early shortwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Receiver
A communications receiver is a type of radio receiver used as a component of a radio communication link. This is in contrast to a ''broadcast receiver'' which is used to receive radio broadcasts. A communication receiver receives parts of the radio spectrum not used for broadcasting, that includes amateur, military, aircraft, marine, and other bands. They are often used with a radio transmitter as part of a two-way radio link for shortwave radio or amateur radio communication, although they are also used for shortwave listening. Features Commercial communications receivers are characterized by high stability and reliability of performance, and are generally adapted for remote control and monitoring. For marketing purposes, many hobby-type receivers are advertised as "communications receivers" although none are suited for heavy-duty, reliable 24-hour use as the primary form of communication for an isolated station. Typically, a communications receiver is of the superheterod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transceiver
In radio communication, a transceiver is an electronic device which is a combination of a radio ''trans''mitter and a re''ceiver'', hence the name. It can both transmit and receive radio waves using an antenna, for communication purposes. These two related functions are often combined in a single device to reduce manufacturing costs. The term is also used for other devices which can both transmit and receive through a communications channel, such as ''optical transceivers'' which transmit and receive light in optical fiber systems, and ''bus transceivers'' which transmit and receive digital data in computer data buses. Radio transceivers are widely used in wireless devices. One large use is in two-way radios, which are audio transceivers used for bidirectional person-to-person voice communication. Examples are cell phones, which transmit and receive the two sides of a phone conversation using radio waves to a cell tower, cordless phones in which both the phone handset ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intermediate Frequency
In communications and electronic engineering, an intermediate frequency (IF) is a frequency to which a carrier wave is shifted as an intermediate step in transmission or reception. The intermediate frequency is created by mixing the carrier signal with a local oscillator signal in a process called heterodyning, resulting in a signal at the difference or beat frequency. Intermediate frequencies are used in superheterodyne radio receivers, in which an incoming signal is shifted to an IF for amplification before final detection is done. Conversion to an intermediate frequency is useful for several reasons. When several stages of filters are used, they can all be set to a fixed frequency, which makes them easier to build and to tune. Lower frequency transistors generally have higher gains so fewer stages are required. It's easier to make sharply selective filters at lower fixed frequencies. There may be several such stages of intermediate frequency in a superheterodyne receiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IF Amplifier
Intermediate-frequency (IF) amplifiers are amplifier stages used to raise signal levels in radio and television receivers, at frequencies intermediate to the higher radio-frequency (RF) signal from the antenna and the lower (baseband) audio or video frequency that the receiver is recovering. Uses IF amplifiers in heterodyne receivers apply gain in a frequency band between the input radio frequency and output audio frequency or video frequency, often following one stage of RF amplifier A radio-frequency power amplifier (RF power amplifier) is a type of electronic amplifier that converts a low-power radio-frequency signal into a higher-power signal. Typically, RF power amplifiers drive the antenna of a transmitter. Design goa .... This allows most of the gain in the form of a fixed-frequency amplifier, simplifying tuning. Compare to its predecessor, the tuned RF receiver. IF amplifiers might use double-tuned amplifiers or staggered tuning to generate the appropriate f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplitude Modulation
Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the amplitude (signal strength) of the wave is varied in proportion to that of the message signal, such as an audio signal. This technique contrasts with angle modulation, in which either the frequency of the carrier wave is varied, as in frequency modulation, or its phase, as in phase modulation. AM was the earliest modulation method used for transmitting audio in radio broadcasting. It was developed during the first quarter of the 20th century beginning with Roberto Landell de Moura and Reginald Fessenden's radiotelephone experiments in 1900. This original form of AM is sometimes called double-sideband amplitude modulation (DSBAM), because the standard method produces sidebands on either side of the carrier frequency. Single-sideband modulation uses bandpass filters to eliminate one of the sidebands ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single Sideband
In radio communications, single-sideband modulation (SSB) or single-sideband suppressed-carrier modulation (SSB-SC) is a type of modulation used to transmit information, such as an audio signal, by radio waves. A refinement of amplitude modulation, it uses transmitter power and bandwidth more efficiently. Amplitude modulation produces an output signal the bandwidth of which is twice the maximum frequency of the original baseband signal. Single-sideband modulation avoids this bandwidth increase, and the power wasted on a carrier, at the cost of increased device complexity and more difficult tuning at the receiver. Basic concept Radio transmitters work by mixing a radio frequency (RF) signal of a specific frequency, the carrier wave, with the audio signal to be broadcast. In AM transmitters this mixing usually takes place in the final RF amplifier (high level modulation). It is less common and much less efficient to do the mixing at low power and then amplify it in a linear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Modulation
Frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. The technology is used in telecommunications, radio broadcasting, signal processing, and computing. In analog frequency modulation, such as radio broadcasting, of an audio signal representing voice or music, the instantaneous frequency deviation, i.e. the difference between the frequency of the carrier and its center frequency, has a functional relation to the modulating signal amplitude. Digital data can be encoded and transmitted with a type of frequency modulation known as frequency-shift keying (FSK), in which the instantaneous frequency of the carrier is shifted among a set of frequencies. The frequencies may represent digits, such as '0' and '1'. FSK is widely used in computer modems, such as fax modems, telephone caller ID systems, garage door openers, and other low-frequency transmissions. Radioteletype also uses FSK. Frequency modulatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Electronics
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves, and received by another antenna connected to a radio receiver. Radio is very widely used in modern technology, in radio communication, radar, radio navigation, remote control, remote sensing, and other applications. In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking, and satellite communication, among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the transmitter. In radar, used to locate and track objects like aircraft, ships, spacecraft a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
