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Television Detector Van
TV detector vans are vans which contain equipment that can detect the presence of television sets in use. These vans have been used by the General Post Office and later by contractors working for the BBC to enforce the television licensing system in the UK, the Channel Islands and on the Isle of Man. History When television broadcasts in the UK were resumed after a break due to World War II, it was decided to introduce a television licence fee to finance the service. When first introduced on 1 June 1946, the licence covering the monochrome-only single-channel BBC television service cost £2 (equivalent to £ as of ). The licence was originally issued by the General Post Office (GPO), which was then the regulator of public communications within the UK. Since it was not possible to stop people without a licence from buying and operating a TV, it was necessary to find ways of enforcing the TV licence system. One of the methods used to identify TV use without a licence was TV detect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BLW TV Detector Van
BLW or blw may refer to: * Baby-led weaning, an approach to adding complementary foods to a baby's diet of breast milk or formula * Baldwin Locomotive Works, a defunct American manufacturer of railroad locomotives * Brightline West, a future high-speed rail route * BLW, the IATA code for Beledweyne Airport, Somalia * BLW, the Indian Railways station code for Balawali railway station Balawali railway station is a railway station on Moradabad–Ambala line under the Moradabad railway division of Northern Railway zone. It is situated at Forest Range-1, Balawali in Bijnor district of the Indian state of Uttar Pradesh U ..., Uttar Pradesh, India * blw, the ISO 639-3 code for Balangao language, Luzon, Philippines {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oscilloscope
An oscilloscope (formerly known as an oscillograph, informally scope or O-scope) is a type of electronic test instrument that graphically displays varying voltages of one or more signals as a function of time. Their main purpose is capturing information on electrical signals for debugging, analysis, or characterization. The displayed waveform can then be analyzed for properties such as amplitude, frequency, rise time, time interval, distortion, and others. Originally, calculation of these values required manually measuring the waveform against the scales built into the screen of the instrument. Modern digital instruments may calculate and display these properties directly. Oscilloscopes are used in the sciences, engineering, biomedical, automotive and the telecommunications industry. General-purpose instruments are used for maintenance of electronic equipment and laboratory work. Special-purpose oscilloscopes may be used to analyze an automotive ignition system or to display th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Band II
Band II is the range of radio frequencies within the very high frequency (VHF) part of the electromagnetic spectrum from 87.5 to 108.0 megahertz (MHz). Radio Band II is primarily used worldwide for FM radio broadcasting. Broadcast television Usage in Russia and in other former members of OIRT In the former Soviet Union and other countries-members of OIRT The International Radio and Television Organisation (official name in French: Organisation Internationale de Radiodiffusion et de Télévision or OIRT (before 1960 International Broadcasting Organization (IBO), official name in French: ''Organ ..., frequencies from 76 MHz to 100 MHz were designated for broadcast television usage. Considering 8 MHz channel bandwidth used by the Russian analog television system ( System D), the following television channels had been defined: Broadcast television channels 1 and 2 are assigned to VHF I band, channels 6 to 12 are assigned to VHF III band. Starti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Band I
Band I is a range of radio frequencies within the very high frequency (VHF) part of the electromagnetic spectrum. The first time there was defined "for simplicity" in Annex 1 of "Final acts of the European Broadcasting Conference in the VHF and UHF bands - Stockholm, 1961". Band I ranges from 47 to 68 MHz for the European Broadcasting Area, and from 54 to 88 MHz for the Americas and it is primarily used for television broadcasting in compliance with ITU Radio Regulations (article 1.38). With the transition to digital TV, most Band I transmitters have already been switched off. Television broadcasting usage Channel spacings vary from country to country, with spacings of 6, 7 and 8 MHz being common. In the UK, Band I was originally used by the BBC for monochrome 405-line television; likewise, the French former 455-line (1937–1939) then 441-line (1943–1956) transmitter on the Eiffel Tower in Paris, and some stations of the French monochrome 819-line system used Band I. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
405-line Television System
The 405-line monochrome analogue television broadcasting system was the first fully electronic television system to be used in regular broadcasting. The number of television lines influences the image resolution, or quality of the picture. It was introduced with the BBC Television Service in 1936, suspended for the duration of World War II, and remained in operation in the UK until 1985. It was also used between 1961 and 1982 in Ireland, as well as from 1957 to 1973 for the Rediffusion Television cable service in Hong Kong. 405-line was approved as System A in the CCIR assignment of broadcast systems. Sometimes called the Marconi-EMI system, it was developed in 1934 by the EMI Research Team led by Isaac Shoenberg. The figure of 405 lines had been chosen following discussions over Sunday lunch at the home of Alan Blumlein. The system used interlacing; EMI had been experimenting with a 243-line all-electronic interlaced system since 1933. In the 405 system the scanning l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superheterodyne Receiver
A superheterodyne receiver, often shortened to superhet, is a type of radio receiver that uses frequency mixing to convert a received signal to a fixed intermediate frequency (IF) which can be more conveniently processed than the original carrier frequency. It was invented by French radio engineer and radio manufacturer Lucien Lévy. Virtually all modern radio receivers use the superheterodyne principle. Precursors Early radio Early Morse code radio broadcasts were produced using an alternator connected to a spark gap. The output signal was at a carrier frequency defined by the physical construction of the gap, modulated by the alternating current signal from the alternator. Since the output frequency of the alternator was generally in the audible range, this produces an audible amplitude modulated (AM) signal. Simple radio detectors filtered out the high-frequency carrier, leaving the modulation, which was passed on to the user's headphones as an audible signal of do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Independent Television Authority
The Independent Television Authority (ITA) was an agency created by the Television Act 1954 ( 2 & 3 Eliz. 2. c. 55) to supervise the creation of " Independent Television" (ITV), the first commercial television network in the United Kingdom. The ITA existed from 1954 until 1972. It was responsible for determining the location, constructing, building, and operating the transmission stations used by the ITV network, as well as determining the franchise areas and awarding the franchises for each regional commercial broadcaster. The authority began its operations on 4 August 1954, a mere four days after the Television Act 1954 received royal assent, under the chairmanship of Sir Kenneth Clark. The authority's first director general, Sir Robert Fraser was appointed by Clark a month later on 14 September. The physics of VHF broadcasting meant that a comparatively small number of transmitters could cover the majority of the population of Britain, if not the bulk of the area of the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CW Radio
Wireless telegraphy or radiotelegraphy is the transmission of text messages by radio waves, analogous to electrical telegraphy using cables. Before about 1910, the term ''wireless telegraphy'' was also used for other experimental technologies for transmitting telegraph signals without wires. In radiotelegraphy, information is transmitted by pulses of radio waves of two different lengths called "dots" and "dashes", which spell out text messages, usually in Morse code. In a manual system, the sending operator taps on a switch called a telegraph key which turns the transmitter on and off, producing the pulses of radio waves. At the receiver the pulses are audible in the receiver's speaker as beeps, which are translated back to text by an operator who knows Morse code. Radiotelegraphy was the first means of radio communication. The first practical radio transmitters and receivers invented in 1894–1895 by Guglielmo Marconi used radiotelegraphy. It continued to be the only type of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
