Single Channel Ground and Airborne Radio System ( SINCGARS ) is a very high frequency combat network radio (CNR) used by U.S. and allied military forces. In the CNR network, the SINCGARS’ primary role is voice transmission between surface and airborne command and control (C2) assets.
123-501: The SINCGARS family replaced the Vietnam War-era synthesized single frequency radios ( AN/PRC-77 and AN/VRC-12 ), although it can work with them. The airborne AN/ARC-201 radio is phasing out the older tactical air-to-ground radios (AN/ARC-114 and AN/ARC-131). The SINCGARS is designed on a modular basis to achieve maximum commonality among various ground, maritime, and airborne configurations. A common receiver/transmitter (RT)
246-636: A crystal oscillator is common, but other resonators and frequency sources can be used. Incoherent techniques derive frequencies from a set of several stable oscillators. The vast majority of synthesizers in commercial applications use coherent techniques due to simplicity and low cost. Synthesizers used in commercial radio receivers are largely based on phase-locked loops or PLLs. Many types of frequency synthesizer are available as integrated circuits , reducing cost and size. High end receivers and electronic test equipment use more sophisticated techniques, often in combination. A well-thought-out design procedure
369-517: A crystal oscillator . Three types of synthesizer can be distinguished. The first and second type are routinely found as stand-alone architecture: direct analog synthesis (also called a mix-filter-divide architecture as found in the 1960s e.g., HP 5100A and the more modern direct digital synthesizer (DDS) ( table lookup ). The third type are routinely used as communication system IC building blocks: indirect digital ( PLL ) synthesizers including integer-N and fractional-N. The recently emerged TAF-DPS
492-400: A local oscillator , which used a resonant circuit composed of an inductor and capacitor , or sometimes resonant transmission lines, to determine the frequency. The receiver was adjusted to different frequencies by either a variable capacitor, or a switch which chose the proper tuned circuit for the desired channel, such as with the turret tuner commonly used in television receivers prior to
615-458: A patent interference suit against Farnsworth. The U.S. Patent Office examiner disagreed in a 1935 decision, finding priority of invention for Farnsworth against Zworykin. Farnsworth claimed that Zworykin's 1923 system could not produce an electrical image of the type to challenge his patent. Zworykin received a patent in 1928 for a color transmission version of his 1923 patent application. He also divided his original application in 1931. Zworykin
738-477: A prescaler which reduces the frequency to a manageable level. Since the prescaler is part of the overall division ratio, a fixed prescaler can cause problems designing a system with narrow channel spacings – typically encountered in radio applications. This can be overcome using a dual-modulus prescaler . Further practical aspects concern the amount of time the system can switch from channel to channel, time to lock when first switched on, and how much noise there
861-478: A resolution that is substantially higher. HDTV may be transmitted in different formats: 1080p , 1080i and 720p . Since 2010, with the invention of smart television , Internet television has increased the availability of television programs and movies via the Internet through streaming video services such as Netflix, Amazon Prime Video , iPlayer and Hulu . In 2013, 79% of the world's households owned
984-618: A transistor -based UHF tuner . The first fully transistorized color television in the United States was the Quasar television introduced in 1967. These developments made watching color television a more flexible and convenient proposition. In 1972, sales of color sets finally surpassed sales of black-and-white sets. Color broadcasting in Europe was not standardized on the PAL format until
1107-467: A tuner for receiving and decoding broadcast signals. A visual display device that lacks a tuner is correctly called a video monitor rather than a television. The television broadcasts are mainly a simplex broadcast meaning that the transmitter cannot receive and the receiver cannot transmit. The word television comes from Ancient Greek τῆλε (tele) 'far' and Latin visio 'sight'. The first documented usage of
1230-483: A 1925 demonstration, the image was dim, had low contrast and poor definition, and was stationary. Zworykin's imaging tube never got beyond the laboratory stage. However, RCA, which acquired the Westinghouse patent, asserted that the patent for Farnsworth's 1927 image dissector was written so broadly that it would exclude any other electronic imaging device. Thus, based on Zworykin's 1923 patent application, RCA filed
1353-403: A 2-inch-wide by 2.5-inch-high screen (5 by 6 cm). The large receiver had a screen 24 inches wide by 30 inches high (60 by 75 cm). Both sets could reproduce reasonably accurate, monochromatic, moving images. Along with the pictures, the sets received synchronized sound. The system transmitted images over two paths: first, a copper wire link from Washington to New York City, then
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#17327830748691476-402: A TV system with a 40-line resolution that employed a CRT display. This was the first working example of a fully electronic television receiver and Takayanagi's team later made improvements to this system parallel to other television developments. Takayanagi did not apply for a patent. In the 1930s, Allen B. DuMont made the first CRTs to last 1,000 hours of use, one of the factors that led to
1599-454: A base time unit, TAF-DPS first creates two types of cycles T A and T B . These two types of cycles are then used in an interleaved fashion to produce the clock pulse train. As a result, TAF-DPS is able to address the problems of arbitrary-frequency-generation and instantaneous-frequency-switching more effectively. The first circuit technology of utilizing the TAF concept (although subconsciously)
1722-683: A camera tube, using the CRT instead as a flying-spot scanner to scan slides and film. Ardenne achieved his first transmission of television pictures on 24 December 1933, followed by test runs for a public television service in 1934. The world's first electronically scanned television service then started in Berlin in 1935, the Fernsehsender Paul Nipkow , culminating in the live broadcast of the 1936 Summer Olympic Games from Berlin to public places all over Germany. Philo Farnsworth gave
1845-557: A channel separation of 25 kilohertz (kHz). It accepts either digital or analog inputs and superimposes the signal onto a radio frequency (RF) carrier wave. In FH mode, the input changes frequency about 100 times per second over portions of the tactical VHF-FM range. These continual changes in frequency hinder threat interception and jamming units from locating or disrupting friendly communications. The SINCGARS provides data rates up to 16,000 bits per second. Enhanced data modes provide packet and RS-232 data. The enhanced data modes available with
1968-609: A color television combining a traditional black-and-white display with a rotating colored disk. This device was very "deep" but was later improved with a mirror folding the light path into an entirely practical device resembling a large conventional console. However, Baird was unhappy with the design, and, as early as 1944, had commented to a British government committee that a fully electronic device would be better. In 1939, Hungarian engineer Peter Carl Goldmark introduced an electro-mechanical system while at CBS , which contained an Iconoscope sensor. The CBS field-sequential color system
2091-409: A communal viewing experience to a solitary viewing experience. By 1960, Sony had sold over 4 million portable television sets worldwide. The basic idea of using three monochrome images to produce a color image had been experimented with almost as soon as black-and-white televisions had first been built. Although he gave no practical details, among the earliest published proposals for television
2214-819: A fellow of the Royal Society (UK), published a letter in the scientific journal Nature in which he described how "distant electric vision" could be achieved by using a cathode-ray tube, or Braun tube, as both a transmitting and receiving device, he expanded on his vision in a speech given in London in 1911 and reported in The Times and the Journal of the Röntgen Society. In a letter to Nature published in October 1926, Campbell-Swinton also announced
2337-423: A lensed disk scanner with a 48-line resolution. He was granted U.S. Patent No. 1,544,156 (Transmitting Pictures over Wireless) on 30 June 1925 (filed 13 March 1922). Herbert E. Ives and Frank Gray of Bell Telephone Laboratories gave a dramatic demonstration of mechanical television on 7 April 1927. Their reflected-light television system included both small and large viewing screens. The small receiver had
2460-690: A line of the image. Although he never built a working model of the system, variations of Nipkow's spinning-disk " image rasterizer " became exceedingly common. Constantin Perskyi had coined the word television in a paper read to the International Electricity Congress at the International World Fair in Paris on 24 August 1900. Perskyi's paper reviewed the existing electromechanical technologies, mentioning
2583-521: A medium" dates from 1927. The term telly is more common in the UK. The slang term "the tube" or the "boob tube" derives from the bulky cathode-ray tube used on most TVs until the advent of flat-screen TVs . Another slang term for the TV is "idiot box." Facsimile transmission systems for still photographs pioneered methods of mechanical scanning of images in the early 19th century. Alexander Bain introduced
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#17327830748692706-465: A much wider band. A large number of crystals increases cost and requires greater space. The solution to this was the development of circuits which could generate multiple frequencies from a "reference frequency" produced by a crystal oscillator. This is called a frequency synthesizer. The new "synthesized" frequencies would have the frequency stability of the master crystal oscillator, since they were derived from it. Many techniques have been devised over
2829-409: A new member to the frequency synthesizer family. It focuses on frequency generation for clock signal driving integrated circuit . Different from all other techniques, it uses a novel concept of Time-Average-Frequency. Its aim is to address the two long-lasting problems in the field of on-chip clock signal generation: arbitrary-frequency-generation and instantaneous-frequency-switching. Starting from
2952-442: A phosphor plate. The phosphor was patterned so the electrons from the guns only fell on one side of the patterning or the other. Using cyan and magenta phosphors, a reasonable limited-color image could be obtained. He also demonstrated the same system using monochrome signals to produce a 3D image (called " stereoscopic " at the time). A demonstration on 16 August 1944 was the first example of a practical color television system. Work on
3075-428: A power amplifier increases the line of sight (LOS) range to approximately 40 km (25 miles). (These ranges are for planning purposes only; terrain, weather, and antenna height can affect transmission range.) The variable output power level allows users to operate on the minimum power necessary to maintain reliable communications, thus lessening the electromagnetic signature given off by their radio sets. This capability
3198-471: A production model was halted by the SCAP after World War II . Because only a limited number of holes could be made in the disks, and disks beyond a certain diameter became impractical, image resolution on mechanical television broadcasts was relatively low, ranging from about 30 lines up to 120 or so. Nevertheless, the image quality of 30-line transmissions steadily improved with technical advances, and by 1933
3321-506: A projection screen at London's Dominion Theatre . Mechanically scanned color television was also demonstrated by Bell Laboratories in June 1929 using three complete systems of photoelectric cells , amplifiers, glow-tubes, and color filters, with a series of mirrors to superimpose the red, green, and blue images into one full-color image. The first practical hybrid system was again pioneered by John Logie Baird. In 1940 he publicly demonstrated
3444-591: A radio link from Whippany, New Jersey . Comparing the two transmission methods, viewers noted no difference in quality. Subjects of the telecast included Secretary of Commerce Herbert Hoover . A flying-spot scanner beam illuminated these subjects. The scanner that produced the beam had a 50-aperture disk. The disc revolved at a rate of 18 frames per second, capturing one frame about every 56 milliseconds . (Today's systems typically transmit 30 or 60 frames per second, or one frame every 33.3 or 16.7 milliseconds, respectively.) Television historian Albert Abramson underscored
3567-616: A resolution that was not surpassed until May 1932 by RCA, with 120 lines. On 25 December 1926, Kenjiro Takayanagi demonstrated a television system with a 40-line resolution that employed a Nipkow disk scanner and CRT display at Hamamatsu Industrial High School in Japan. This prototype is still on display at the Takayanagi Memorial Museum in Shizuoka University , Hamamatsu Campus. His research in creating
3690-641: A signal reportedly to the 60th power or better and showed great promise in all fields of electronics. Unfortunately, an issue with the multipactor was that it wore out at an unsatisfactory rate. At the Berlin Radio Show in August 1931 in Berlin , Manfred von Ardenne gave a public demonstration of a television system using a CRT for both transmission and reception, the first completely electronic television transmission. However, Ardenne had not developed
3813-410: A static photocell. The thallium sulfide (Thalofide) cell, developed by Theodore Case in the U.S., detected the light reflected from the subject and converted it into a proportional electrical signal. This was transmitted by AM radio waves to a receiver unit, where the video signal was applied to a neon light behind a second Nipkow disk rotating synchronized with the first. The brightness of the neon lamp
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3936-430: A synthesizer is used, we are not after a huge range, but rather a finite number over some defined range, such as a number of radio channels in a specific band. Many radio applications require frequencies that are higher than can be directly input to the digital counter. To overcome this, the entire counter could be constructed using high-speed logic such as ECL , or more commonly, using a fast initial division stage called
4059-464: A system that used a mechanical mirror-drum scanner to transmit, in Zworykin's words, "very crude images" over wires to the " Braun tube" ( cathode-ray tube or "CRT") in the receiver. Moving images were not possible because, in the scanner: "the sensitivity was not enough and the selenium cell was very laggy". In 1921, Édouard Belin sent the first image via radio waves with his belinograph . By
4182-521: A television set. The replacement of earlier cathode-ray tube (CRT) screen displays with compact, energy-efficient, flat-panel alternative technologies such as LCDs (both fluorescent-backlit and LED ), OLED displays, and plasma displays was a hardware revolution that began with computer monitors in the late 1990s. Most television sets sold in the 2000s they were still CRT , it was only in early 2010s that flat screen TVs have started to overtake CRT TVs once and for all. Major manufacturers announced
4305-484: A television system using fully electronic scanning and display elements and employing the principle of "charge storage" within the scanning (or "camera") tube. The problem of low sensitivity to light resulting in low electrical output from transmitting or "camera" tubes would be solved with the introduction of charge-storage technology by Kálmán Tihanyi beginning in 1924. His solution was a camera tube that accumulated and stored electrical charges ("photoelectrons") within
4428-443: A very wide range of frequencies, because the comparator will have a limited bandwidth and may suffer from aliasing problems. This would lead to false locking situations, or an inability to lock at all. In addition, it is hard to make a high frequency VCO that operates over a very wide range. This is due to several factors, but the primary restriction is the limited capacitance range of varactor diodes . However, in most systems where
4551-400: Is digital in nature, is very easy to interface to other digital components or a microprocessor . This allows the frequency output by the synthesizer to be easily controlled by a digital system. Suppose the reference signal is 100 kHz, and the divider can be preset to any value between 1 and 100. The error signal produced by the comparator will only be zero when the output of the divider
4674-456: Is a mass medium for advertising, entertainment, news, and sports. The medium is capable of more than " radio broadcasting ," which refers to an audio signal sent to radio receivers . Television became available in crude experimental forms in the 1920s, but only after several years of further development was the new technology marketed to consumers. After World War II , an improved form of black-and-white television broadcasting became popular in
4797-582: Is a circuit level enabler for system level innovation. It can be used in many areas other than clock signal generation. Its impact is significant since clock signal is the most important signal in electronics, establishing the flow-of-time inside the electronic world. This profound influence is being seen in this directional change in Moore's Law from space to time. Prior to widespread use of synthesizers, in order to pick up stations on different frequencies, radio and television receivers relied on manual tuning of
4920-572: Is added to the output of the loop filter, directly varying the frequency of the VCO and the synthesizer output. The modulation will also appear at the phase comparator output, reduced in amplitude by any frequency division. Any spectral components in the modulating signal too low to be blocked by the loop filter end up back at the VCO input with opposite polarity to the modulating signal, thus cancelling them out. (The loop effectively sees these components as VCO noise to be tracked out.) Modulation components above
5043-490: Is also 100 kHz. For this to be the case, the VCO must run at a frequency which is 100 kHz x the divider count value. Thus it will produce an output of 100 kHz for a count of 1, 200 kHz for a count of 2, 1 MHz for a count of 10 and so on. Note that only whole multiples of the reference frequency can be obtained with the simplest integer N dividers. Fractional N dividers are readily available. In practice this type of frequency synthesizer cannot operate over
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5166-425: Is also a direct approach. It directly constructs the waveform of each pulse in the clock pulse train. A digiphase synthesizer is in some ways similar to a DDS, but it has architectural differences. One of its advantages is to allow a much finer resolution than other types of synthesizers with a given reference frequency. Recently, a technique named Time-Average-Frequency Direct Period Synthesis (TAF-DPS) emerges as
5289-1036: Is considered to be the first significant step to a successful synthesizer project. In the system design of a frequency synthesizer, states Manassewitsch, there are as many "best" design procedures as there are experienced synthesizer designers. System analysis of a frequency synthesizer involves output frequency range (or frequency bandwidth or tuning range), frequency increments (or resolution or frequency tuning), frequency stability (or phase stability, compare spurious outputs), phase noise performance (e.g., spectral purity), switching time (compare settling time and rise time ), and size, power consumption, and cost. James A. Crawford says that these are mutually contradictive requirements. Influential early books on frequency synthesis techniques include those by Floyd M. Gardner (his 1966 Phaselock techniques ) and by Venceslav F. Kroupa (his 1973 Frequency Synthesis ). Mathematical techniques analogous to mechanical gear-ratio relationships can be employed in frequency synthesis when
5412-405: Is in the output. All of these are a function of the loop filter of the system, which is a low-pass filter placed between the output of the frequency comparator and the input of the VCO. Usually the output of a frequency comparator is in the form of short error pulses, but the input of the VCO must be a smooth noise-free DC voltage. (Any noise on this signal naturally causes frequency modulation of
5535-542: Is of particular importance at major command posts, which operate in multiple networks. SC CNR users outside the FH network can use a hailing method to request access to the network. When hailing a network, a user outside the network contacts the network control station (NCS) on the cue frequency. In the active FH mode, the SINCGARS gives audible and visual signals to the operator that an external subscriber wants to communicate with
5658-399: Is proportional to the difference between their phases. The error signal is then low pass filtered and used to drive a voltage-controlled oscillator (VCO) which creates an output frequency. The output frequency is fed through a frequency divider back to the input of the system, producing a negative feedback loop. If the output frequency drifts, the phase error signal will increase, driving
5781-437: Is the divider placed between the output and the feedback input. This is usually in the form of a digital counter , with the output signal acting as a clock signal . The counter is preset to some initial count value, and counts down at each cycle of the clock signal. When it reaches zero, the counter output changes state and the count value is reloaded. This circuit is straightforward to implement using flip-flops , and because it
5904-416: Is the “ Flying-Adder frequency synthesis architecture or“ Flying-Adder PLL ”, which is developed in late 1990s. Since the introduction of TAF concept in 2008, the development of a frequency synthesis technology that works on TAF formally kicks off. A detailed description of this technology can be found in those books and this short tutorial . As development progresses, it gradually becomes clear that TAF-DPS
6027-572: Is to employ many crystals, one for each frequency desired, and switch the correct one into the circuit. This "brute force" technique is practical when only a handful of frequencies are required, but quickly becomes costly and impractical in many applications. For example, the FM radio band in many countries supports 100 individual channel frequencies from about 88 to 108 MHz ; the ability to tune in each channel would require 100 crystals. Cable television can support even more frequencies or channels over
6150-527: Is used in the ground configurations. The modular design also reduces the burden on the logistics system to provide repair parts. The SINCGARS can operate in either the single-channel (SC) or frequency hopping (FH) mode, and stores both SC frequencies and FH loadsets. The system is compatible with all current U.S. and allied VHF-frequency modulation (FM) radios in the SC, nonsecure mode. The SINCGARS operates on any of 2320 channels between 30 and 88 megahertz (MHz) with
6273-520: The 1939 New York World's Fair . On the other hand, in 1934, Zworykin shared some patent rights with the German licensee company Telefunken. The "image iconoscope" ("Superikonoskop" in Germany) was produced as a result of the collaboration. This tube is essentially identical to the super-Emitron. The production and commercialization of the super-Emitron and image iconoscope in Europe were not affected by
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#17327830748696396-748: The EMI engineering team led by Isaac Shoenberg applied in 1932 for a patent for a new device they called "the Emitron", which formed the heart of the cameras they designed for the BBC. On 2 November 1936, a 405-line broadcasting service employing the Emitron began at studios in Alexandra Palace and transmitted from a specially built mast atop one of the Victorian building's towers. It alternated briefly with Baird's mechanical system in adjoining studios but
6519-479: The patent war between Zworykin and Farnsworth because Dieckmann and Hell had priority in Germany for the invention of the image dissector, having submitted a patent application for their Lichtelektrische Bildzerlegerröhre für Fernseher ( Photoelectric Image Dissector Tube for Television ) in Germany in 1925, two years before Farnsworth did the same in the United States. The image iconoscope (Superikonoskop) became
6642-404: The "Iconoscope" by Zworykin, the new tube had a light sensitivity of about 75,000 lux , and thus was claimed to be much more sensitive than Farnsworth's image dissector. However, Farnsworth had overcome his power issues with his Image Dissector through the invention of a completely unique " Multipactor " device that he began work on in 1930, and demonstrated in 1931. This small tube could amplify
6765-661: The 1920s, when amplification made television practical, Scottish inventor John Logie Baird employed the Nipkow disk in his prototype video systems. On 25 March 1925, Baird gave the first public demonstration of televised silhouette images in motion at Selfridges 's department store in London . Since human faces had inadequate contrast to show up on his primitive system, he televised a ventriloquist's dummy named "Stooky Bill," whose painted face had higher contrast, talking and moving. By 26 January 1926, he had demonstrated before members of
6888-421: The 1960s, and broadcasts did not start until 1967. By this point, many of the technical issues in the early sets had been worked out, and the spread of color sets in Europe was fairly rapid. By the mid-1970s, the only stations broadcasting in black-and-white were a few high-numbered UHF stations in small markets and a handful of low-power repeater stations in even smaller markets such as vacation spots. By 1979, even
7011-423: The 1980s. However the resonant frequency of a tuned circuit is not very stable; variations in temperature and aging of components caused frequency drift , causing the receiver to drift off the station frequency. Automatic frequency control (AFC) solves some of the drift problem, but manual retuning was often necessary. Since transmitter frequencies are stabilized, an accurate source of fixed, stable frequencies in
7134-561: The AN/ARC-188 for communications between Air Force aircraft and Army units. Frequency synthesizer A frequency synthesizer is an electronic circuit that generates a range of frequencies from a single reference frequency. Frequency synthesizers are used in devices such as radio receivers , televisions , mobile telephones , radiotelephones , walkie-talkies , CB radios , cable television converter boxes , satellite receivers, and GPS systems. A frequency synthesizer may use
7257-679: The Dutch company Philips produced and commercialized the image iconoscope and multicon from 1952 to 1958. U.S. television broadcasting, at the time, consisted of a variety of markets in a wide range of sizes, each competing for programming and dominance with separate technology until deals were made and standards agreed upon in 1941. RCA, for example, used only Iconoscopes in the New York area, but Farnsworth Image Dissectors in Philadelphia and San Francisco. In September 1939, RCA agreed to pay
7380-442: The FH network. The SINCGARS operator must change to the cue frequency to communicate with the outside radio system. The network can be set to a manual frequency for initial network activation. The manual frequency provides a common frequency for all members of the network to verify that the equipment is operational. During initial net activation, all operators in the net tune to the manual frequency. After communications are established,
7503-653: The Farnsworth Television and Radio Corporation royalties over the next ten years for access to Farnsworth's patents. With this historic agreement in place, RCA integrated much of what was best about the Farnsworth Technology into their systems. In 1941, the United States implemented 525-line television. Electrical engineer Benjamin Adler played a prominent role in the development of television. The world's first 625-line television standard
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#17327830748697626-470: The Royal Institution the transmission of an image of a face in motion by radio. This is widely regarded as the world's first true public television demonstration, exhibiting light, shade, and detail. Baird's system used the Nipkow disk for both scanning the image and displaying it. A brightly illuminated subject was placed in front of a spinning Nipkow disk set with lenses that swept images across
7749-560: The Science Museum, South Kensington. In 1928, Baird's company (Baird Television Development Company/Cinema Television) broadcast the first transatlantic television signal between London and New York and the first shore-to-ship transmission. In 1929, he became involved in the first experimental mechanical television service in Germany. In November of the same year, Baird and Bernard Natan of Pathé established France's first television company, Télévision- Baird -Natan. In 1931, he made
7872-536: The System Improvement Program (SIP) and Advanced System Improvement Program (ASIP) radios also enable forward error correction (FEC), and increased speed, range, and accuracy of data transmissions. Most ground SINCGARS have the capability to control output power; however, most airborne SINCGARS are fixed power. Those RTs with power settings can vary transmission range from approximately 200 meters (660 feet) to 10 kilometers (km) (6.2 miles). Adding
7995-465: The Telechrome continued, and plans were made to introduce a three-gun version for full color. However, Baird's untimely death in 1946 ended the development of the Telechrome system. Similar concepts were common through the 1940s and 1950s, differing primarily in the way they re-combined the colors generated by the three guns. The Geer tube was similar to Baird's concept but used small pyramids with
8118-569: The UK broadcasts using the Baird system were remarkably clear. A few systems ranging into the 200-line region also went on the air. Two of these were the 180-line system that Compagnie des Compteurs (CDC) installed in Paris in 1935 and the 180-line system that Peck Television Corp. started in 1935 at station VE9AK in Montreal . The advancement of all-electronic television (including image dissectors and other camera tubes and cathode-ray tubes for
8241-761: The United Kingdom and the United States, and television sets became commonplace in homes, businesses, and institutions. During the 1950s, television was the primary medium for influencing public opinion . In the mid-1960s, color broadcasting was introduced in the U.S. and most other developed countries. The availability of various types of archival storage media such as Betamax and VHS tapes, LaserDiscs , high-capacity hard disk drives , CDs , DVDs , flash drives , high-definition HD DVDs and Blu-ray Discs , and cloud digital video recorders has enabled viewers to watch pre-recorded material—such as movies—at home on their own time schedule. For many reasons, especially
8364-462: The VCO.) Heavy filtering will make the VCO slow to respond to changes, causing drift and slow response time, but light filtering will produce noise and other problems with harmonics . Thus the design of the filter is critical to the performance of the system and in fact the main area that a designer will concentrate on when building a synthesizer system. Many PLL frequency synthesizers can also generate frequency modulation (FM). The modulating signal
8487-427: The above limitation. Modulation is applied to the VCO as before, but now is also applied digitally to the synthesizer in sympathy with the analog FM signal using a fast delta sigma ADC. Television Television ( TV ) is a telecommunication medium for transmitting moving images and sound. Additionally, the term can refer to a physical television set rather than the medium of transmission . Television
8610-413: The advanced SIP (ASIP) models, which are less than half the size and weight of ICOM and SIP models and provided enhanced FEC ( forward error correction ) data modes, RS-232 asynchronous data, packet data formats, and direct interfacing to Precision Lightweight GPS Receiver (PLGR) devices providing radio level situational awareness capability. In 1992, the U.S. Air Force awarded a contract to replace
8733-461: The analog and channel-separated signals used by analog television . Due to data compression , digital television can support more than one program in the same channel bandwidth. It is an innovative service that represents the most significant evolution in television broadcast technology since color television emerged in the 1950s. Digital television's roots have been tied very closely to the availability of inexpensive, high performance computers . It
8856-462: The convenience of remote retrieval, the storage of television and video programming now also occurs on the cloud (such as the video-on-demand service by Netflix ). At the beginning of the 2010s, digital television transmissions greatly increased in popularity. Another development was the move from standard-definition television (SDTV) ( 576i , with 576 interlaced lines of resolution and 480i ) to high-definition television (HDTV), which provides
8979-498: The design of RCA 's " iconoscope " in 1931, the U.S. patent for Tihanyi's transmitting tube would not be granted until May 1939. The patent for his receiving tube had been granted the previous October. Both patents had been purchased by RCA prior to their approval. Charge storage remains a basic principle in the design of imaging devices for television to the present day. On 25 December 1926, at Hamamatsu Industrial High School in Japan, Japanese inventor Kenjiro Takayanagi demonstrated
9102-525: The development of HDTV technology, the MUSE analog format proposed by NHK , a Japanese company, was seen as a pacesetter that threatened to eclipse U.S. electronics companies' technologies. Until June 1990, the Japanese MUSE standard, based on an analog system, was the front-runner among the more than 23 other technical concepts under consideration. Then, a U.S. company, General Instrument, demonstrated
9225-535: The discontinuation of CRT, Digital Light Processing (DLP), plasma, and even fluorescent-backlit LCDs by the mid-2010s. LEDs are being gradually replaced by OLEDs. Also, major manufacturers have started increasingly producing smart TVs in the mid-2010s. Smart TVs with integrated Internet and Web 2.0 functions became the dominant form of television by the late 2010s. Television signals were initially distributed only as terrestrial television using high-powered radio-frequency television transmitters to broadcast
9348-421: The extra information in the signal and produce a limited-resolution color display. The higher-resolution black-and-white and lower-resolution color images combine in the brain to produce a seemingly high-resolution color image. The NTSC standard represented a significant technical achievement. The first color broadcast (the first episode of the live program The Marriage ) occurred on 8 July 1954. However, during
9471-472: The facsimile machine between 1843 and 1846. Frederick Bakewell demonstrated a working laboratory version in 1851. Willoughby Smith discovered the photoconductivity of the element selenium in 1873. As a 23-year-old German university student, Paul Julius Gottlieb Nipkow proposed and patented the Nipkow disk in 1884 in Berlin . This was a spinning disk with a spiral pattern of holes, so each hole scanned
9594-440: The first outdoor remote broadcast of The Derby . In 1932, he demonstrated ultra-short wave television. Baird's mechanical system reached a peak of 240 lines of resolution on BBC telecasts in 1936, though the mechanical system did not scan the televised scene directly. Instead, a 17.5 mm film was shot, rapidly developed, and then scanned while the film was still wet. A U.S. inventor, Charles Francis Jenkins , also pioneered
9717-431: The following ten years, most network broadcasts and nearly all local programming continued to be black-and-white. It was not until the mid-1960s that color sets started selling in large numbers, due in part to the color transition of 1965, in which it was announced that over half of all network prime-time programming would be broadcast in color that fall. The first all-color prime-time season came just one year later. In 1972,
9840-449: The frequency in the opposite direction so as to reduce the error. Thus the output is locked to the frequency at the other input. This other input is called the reference and is usually derived from a crystal oscillator, which is very stable in frequency. The block diagram below shows the basic elements and arrangement of a PLL based frequency synthesizer. The key to the ability of a frequency synthesizer to generate multiple frequencies
9963-401: The frequency synthesis factor is a ratio of integers. This method allows for effective planning of distribution and suppression of spectral spurs. Variable-frequency synthesizers, including DDS , are routinely designed using Modulo-N arithmetic to represent phase. A phase locked loop is a feedback control system. It compares the phases of two input signals and produces an error signal that
10086-417: The iconoscope (or Emitron) produced an electronic signal and concluded that its real efficiency was only about 5% of the theoretical maximum. They solved this problem by developing and patenting in 1934 two new camera tubes dubbed super-Emitron and CPS Emitron . The super-Emitron was between ten and fifteen times more sensitive than the original Emitron and iconoscope tubes, and, in some cases, this ratio
10209-693: The industrial standard for public broadcasting in Europe from 1936 until 1960, when it was replaced by the vidicon and plumbicon tubes. Indeed, it represented the European tradition in electronic tubes competing against the American tradition represented by the image orthicon. The German company Heimann produced the Superikonoskop for the 1936 Berlin Olympic Games, later Heimann also produced and commercialized it from 1940 to 1955; finally
10332-437: The invention of the first working transistor at Bell Labs , Sony founder Masaru Ibuka predicted in 1952 that the transition to electronic circuits made of transistors would lead to smaller and more portable television sets. The first fully transistorized, portable solid-state television set was the 8-inch Sony TV8-301 , developed in 1959 and released in 1960. This began the transformation of television viewership from
10455-401: The last holdout among daytime network programs converted to color, resulting in the first completely all-color network season. Early color sets were either floor-standing console models or tabletop versions nearly as bulky and heavy, so in practice they remained firmly anchored in one place. GE 's relatively compact and lightweight Porta-Color set was introduced in the spring of 1966. It used
10578-464: The last of these had converted to color. By the early 1980s, B&W sets had been pushed into niche markets, notably low-power uses, small portable sets, or for use as video monitor screens in lower-cost consumer equipment. By the late 1980s, even these last holdout niche B&W environments had inevitably shifted to color sets. Digital television (DTV) is the transmission of audio and video by digitally processed and multiplexed signals, in contrast to
10701-567: The loop filter cutoff frequency cannot return to the VCO input so they remain in the VCO output. This simple scheme therefore cannot directly handle low frequency (or DC) modulating signals but this is not a problem in the many AC-coupled video and audio FM transmitters that use this method. Such signals may also be placed on a subcarrier above the cutoff frequency of the PLL loop filter. PLL frequency synthesizers can also be modulated at low frequency and down to DC by using two-point modulation to overcome
10824-622: The net switches to the FH mode and the NCS transfers the hopping variables to the outstations. More than 570,000 radios have been purchased. There have been several system improvement programs, including the Integrated Communications Security (ICOM) models, which have provided integrated voice and data encryption, the Special Improvement Program (SIP) models, which add additional data modes, and
10947-466: The original Campbell-Swinton's selenium-coated plate. Although others had experimented with using a cathode-ray tube as a receiver, the concept of using one as a transmitter was novel. The first cathode-ray tube to use a hot cathode was developed by John B. Johnson (who gave his name to the term Johnson noise ) and Harry Weiner Weinhart of Western Electric , and became a commercial product in 1922. In 1926, Hungarian engineer Kálmán Tihanyi designed
11070-456: The phosphors deposited on their outside faces instead of Baird's 3D patterning on a flat surface. The Penetron used three layers of phosphor on top of each other and increased the power of the beam to reach the upper layers when drawing those colors. The Chromatron used a set of focusing wires to select the colored phosphors arranged in vertical stripes on the tube. One of the great technical challenges of introducing color broadcast television
11193-507: The public at this time, viewing of the color field tests was restricted to RCA and CBS engineers and the invited press. The War Production Board halted the manufacture of television and radio equipment for civilian use from 22 April 1942 to 20 August 1945, limiting any opportunity to introduce color television to the general public. As early as 1940, Baird had started work on a fully electronic system he called Telechrome . Early Telechrome devices used two electron guns aimed at either side of
11316-407: The receiver would solve the problem. Quartz crystal resonators are many orders of magnitude more stable than LC circuits and when used to control the frequency of the local oscillator offer adequate stability to keep a receiver in tune. However the resonant frequency of a crystal is determined by its dimensions and cannot be varied to tune the receiver to different frequencies. One solution
11439-512: The receiver, a type of Kerr cell modulated the light, and a series of differently angled mirrors attached to the edge of a rotating disc scanned the modulated beam onto the display screen. A separate circuit regulated synchronization. The 8x8 pixel resolution in this proof-of-concept demonstration was just sufficient to clearly transmit individual letters of the alphabet. An updated image was transmitted "several times" each second. In 1911, Boris Rosing and his student Vladimir Zworykin created
11562-415: The reproducer) marked the start of the end for mechanical systems as the dominant form of television. Mechanical television, despite its inferior image quality and generally smaller picture, would remain the primary television technology until the 1930s. The last mechanical telecasts ended in 1939 at stations run by a lot of public universities in the United States. In 1897, English physicist J. J. Thomson
11685-564: The resolution of the color information to conserve bandwidth. As black-and-white televisions could receive the same transmission and display it in black-and-white, the color system adopted is [backwards] "compatible." ("Compatible Color," featured in RCA advertisements of the period, is mentioned in the song " America ," of West Side Story , 1957.) The brightness image remained compatible with existing black-and-white television sets at slightly reduced resolution. In contrast, color televisions could decode
11808-558: The results of some "not very successful experiments" he had conducted with G. M. Minchin and J. C. M. Stanton. They had attempted to generate an electrical signal by projecting an image onto a selenium-coated metal plate that was simultaneously scanned by a cathode ray beam. These experiments were conducted before March 1914, when Minchin died, but they were later repeated by two different teams in 1937, by H. Miller and J. W. Strange from EMI , and by H. Iams and A. Rose from RCA . Both teams successfully transmitted "very faint" images with
11931-449: The signal to individual television receivers. Alternatively, television signals are distributed by coaxial cable or optical fiber , satellite systems, and, since the 2000s, via the Internet. Until the early 2000s, these were transmitted as analog signals, but a transition to digital television was expected to be completed worldwide by the late 2010s. A standard television set consists of multiple internal electronic circuits , including
12054-595: The significance of the Bell Labs demonstration: "It was, in fact, the best demonstration of a mechanical television system ever made to this time. It would be several years before any other system could even begin to compare with it in picture quality." In 1928, WRGB , then W2XB, was started as the world's first television station. It broadcast from the General Electric facility in Schenectady, NY . It
12177-647: The spectrum of colors at the transmitting end and could not have worked as he described it. Another inventor, Hovannes Adamian , also experimented with color television as early as 1907. The first color television project is claimed by him, and was patented in Germany on 31 March 1908, patent No. 197183, then in Britain, on 1 April 1908, patent No. 7219, in France (patent No. 390326) and in Russia in 1910 (patent No. 17912). Scottish inventor John Logie Baird demonstrated
12300-546: The system was improved further by eliminating a motor generator so that his television system had no mechanical parts. That year, Farnsworth transmitted the first live human images with his system, including a three and a half-inch image of his wife Elma ("Pem") with her eyes closed (possibly due to the bright lighting required). Meanwhile, Vladimir Zworykin also experimented with the cathode-ray tube to create and show images. While working for Westinghouse Electric in 1923, he began to develop an electronic camera tube. However, in
12423-410: The techniques of frequency multiplication , frequency division , direct digital synthesis , frequency mixing , and phase-locked loops to generate its frequencies. The stability and accuracy of the frequency synthesizer's output are related to the stability and accuracy of its reference frequency input. Consequently, synthesizers use stable and accurate reference frequencies, such as those provided by
12546-641: The television. He published an article on "Motion Pictures by Wireless" in 1913, transmitted moving silhouette images for witnesses in December 1923, and on 13 June 1925, publicly demonstrated synchronized transmission of silhouette pictures. In 1925, Jenkins used the Nipkow disk and transmitted the silhouette image of a toy windmill in motion over a distance of 5 miles (8 km), from a naval radio station in Maryland to his laboratory in Washington, D.C., using
12669-546: The term dates back to 1900, when the Russian scientist Constantin Perskyi used it in a paper that he presented in French at the first International Congress of Electricity, which ran from 18 to 25 August 1900 during the International World Fair in Paris. The anglicized version of the term is first attested in 1907, when it was still "...a theoretical system to transmit moving images over telegraph or telephone wires ". It
12792-577: The tube throughout each scanning cycle. The device was first described in a patent application he filed in Hungary in March 1926 for a television system he called "Radioskop". After further refinements included in a 1928 patent application, Tihanyi's patent was declared void in Great Britain in 1930, so he applied for patents in the United States. Although his breakthrough would be incorporated into
12915-522: The use of a CRT as a display device. The Braun tube became the foundation of 20th century television. In 1906 the Germans Max Dieckmann and Gustav Glage produced raster images for the first time in a CRT. In 1907, Russian scientist Boris Rosing used a CRT in the receiving end of an experimental video signal to form a picture. He managed to display simple geometric shapes onto the screen. In 1908, Alan Archibald Campbell-Swinton ,
13038-494: The widespread adoption of television. On 7 September 1927, U.S. inventor Philo Farnsworth 's image dissector camera tube transmitted its first image, a simple straight line, at his laboratory at 202 Green Street in San Francisco. By 3 September 1928, Farnsworth had developed the system sufficiently to hold a demonstration for the press. This is widely regarded as the first electronic television demonstration. In 1929,
13161-430: The work of Nipkow and others. However, it was not until 1907 that developments in amplification tube technology by Lee de Forest and Arthur Korn , among others, made the design practical. The first demonstration of the live transmission of images was by Georges Rignoux and A. Fournier in Paris in 1909. A matrix of 64 selenium cells, individually wired to a mechanical commutator , served as an electronic retina . In
13284-457: The world's first color transmission on 3 July 1928, using scanning discs at the transmitting and receiving ends with three spirals of apertures, each spiral with filters of a different primary color, and three light sources at the receiving end, with a commutator to alternate their illumination. Baird also made the world's first color broadcast on 4 February 1938, sending a mechanically scanned 120-line image from Baird's Crystal Palace studios to
13407-549: The world's first public demonstration of an all-electronic television system, using a live camera, at the Franklin Institute of Philadelphia on 25 August 1934 and for ten days afterward. Mexican inventor Guillermo González Camarena also played an important role in early television. His experiments with television (known as telectroescopía at first) began in 1931 and led to a patent for the "trichromatic field sequential system" color television in 1940. In Britain,
13530-441: The years for synthesizing frequencies. Some approaches include phase locked loops , double mix, triple mix, harmonic, double mix divide, and direct digital synthesis (DDS). The choice of approach depends on several factors, such as cost, complexity, frequency step size, switching rate, phase noise , and spurious output. Coherent techniques generate frequencies derived from a single, stable master oscillator. In most applications,
13653-463: Was "...formed in English or borrowed from French télévision ." In the 19th century and early 20th century, other "...proposals for the name of a then-hypothetical technology for sending pictures over distance were telephote (1880) and televista (1904)." The abbreviation TV is from 1948. The use of the term to mean "a television set " dates from 1941. The use of the term to mean "television as
13776-459: Was able, in his three well-known experiments, to deflect cathode rays, a fundamental function of the modern cathode-ray tube (CRT). The earliest version of the CRT was invented by the German physicist Ferdinand Braun in 1897 and is also known as the "Braun" tube. It was a cold-cathode diode , a modification of the Crookes tube , with a phosphor -coated screen. Braun was the first to conceive
13899-518: Was considerably greater. It was used for outside broadcasting by the BBC, for the first time, on Armistice Day 1937, when the general public could watch on a television set as the King laid a wreath at the Cenotaph. This was the first time that anyone had broadcast a live street scene from cameras installed on the roof of neighboring buildings because neither Farnsworth nor RCA would do the same until
14022-654: Was designed in the Soviet Union in 1944 and became a national standard in 1946. The first broadcast in 625-line standard occurred in Moscow in 1948. The concept of 625 lines per frame was subsequently implemented in the European CCIR standard. In 1936, Kálmán Tihanyi described the principle of plasma display , the first flat-panel display system. Early electronic television sets were large and bulky, with analog circuits made of vacuum tubes . Following
14145-411: Was more reliable and visibly superior. This was the world's first regular "high-definition" television service. The original U.S. iconoscope was noisy, had a high ratio of interference to signal, and ultimately gave disappointing results, especially compared to the high-definition mechanical scanning systems that became available. The EMI team, under the supervision of Isaac Shoenberg , analyzed how
14268-408: Was not until the 1990s that digital television became possible. Digital television was previously not practically possible due to the impractically high bandwidth requirements of uncompressed digital video , requiring around 200 Mbit/s for a standard-definition television (SDTV) signal, and over 1 Gbit/s for high-definition television (HDTV). A digital television service
14391-410: Was one by Maurice Le Blanc in 1880 for a color system, including the first mentions in television literature of line and frame scanning. Polish inventor Jan Szczepanik patented a color television system in 1897, using a selenium photoelectric cell at the transmitter and an electromagnet controlling an oscillating mirror and a moving prism at the receiver. But his system contained no means of analyzing
14514-855: Was partly mechanical, with a disc made of red, blue, and green filters spinning inside the television camera at 1,200 rpm and a similar disc spinning in synchronization in front of the cathode-ray tube inside the receiver set. The system was first demonstrated to the Federal Communications Commission (FCC) on 29 August 1940 and shown to the press on 4 September. CBS began experimental color field tests using film as early as 28 August 1940 and live cameras by 12 November. NBC (owned by RCA) made its first field test of color television on 20 February 1941. CBS began daily color field tests on 1 June 1941. These color systems were not compatible with existing black-and-white television sets , and, as no color television sets were available to
14637-524: Was popularly known as " WGY Television." Meanwhile, in the Soviet Union , Leon Theremin had been developing a mirror drum-based television, starting with 16 lines resolution in 1925, then 32 lines, and eventually 64 using interlacing in 1926. As part of his thesis, on 7 May 1926, he electrically transmitted and then projected near-simultaneous moving images on a 5-square-foot (0.46 m ) screen. By 1927 Theremin had achieved an image of 100 lines,
14760-517: Was proposed in 1986 by Nippon Telegraph and Telephone (NTT) and the Ministry of Posts and Telecommunication (MPT) in Japan, where there were plans to develop an "Integrated Network System" service. However, it was not possible to implement such a digital television service practically until the adoption of DCT video compression technology made it possible in the early 1990s. In the mid-1980s, as Japanese consumer electronics firms forged ahead with
14883-515: Was the desire to conserve bandwidth , potentially three times that of the existing black-and-white standards, and not use an excessive amount of radio spectrum . In the United States, after considerable research, the National Television Systems Committee approved an all-electronic system developed by RCA , which encoded the color information separately from the brightness information and significantly reduced
15006-500: Was unable or unwilling to introduce evidence of a working model of his tube that was based on his 1923 patent application. In September 1939, after losing an appeal in the courts and being determined to go forward with the commercial manufacturing of television equipment, RCA agreed to pay Farnsworth US$ 1 million over ten years, in addition to license payments, to use his patents. In 1933, RCA introduced an improved camera tube that relied on Tihanyi's charge storage principle. Called
15129-419: Was varied in proportion to the brightness of each spot on the image. As each hole in the disk passed by, one scan line of the image was reproduced. Baird's disk had 30 holes, producing an image with only 30 scan lines, just enough to recognize a human face. In 1927, Baird transmitted a signal over 438 miles (705 km) of telephone line between London and Glasgow . Baird's original 'televisor' now resides in
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