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CEA-909
CEA-909 is the ANSI standard for 8VSB/ATSC smart antennas. The basic concept is that the smart antenna either physically rotates toward the signal, or is stationary, but has elements pointed in different directions and uses only those elements that maximize the received signal. This is accomplished by feedback from the control device, such as a digital-to-analog converter box, telling the smart antenna when the signal is stronger or weaker. Analog televisions generally give instant feedback as the signal gets better or worse as you move the antenna. Digital television antennas can be difficult to aim correctly because of the cliff effect and because of delays in decoding and displaying the signal. Smart antennas remove the burden of positioning the antenna for digital TVs and can make the tuning process easier than it was with analog television. Information from TVP9900 document There are two basic modes of operation for a CEA-909 antenna, mode A and mode B. Mode A allows for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smart Antenna
Smart antennas (also known as adaptive array antennas, digital antenna arrays, multiple antennas and, recently, MIMO) are antenna arrays with smart signal processing algorithms used to identify spatial signal signatures such as the direction of arrival (DOA) of the signal, and use them to calculate beamforming vectors which are used to track and locate the antenna beam on the mobile/target. Smart antennas should not be confused with reconfigurable antennas, which have similar capabilities but are single element antennas and not antenna arrays. Smart antenna techniques are used notably in acoustic signal processing, track and scan radar, radio astronomy and radio telescopes, and mostly in cellular systems like W-CDMA, UMTS, and LTE. Smart antennas have many functions: DOA estimation, beamforming, interference nulling, and constant modulus preservation.. Direction of arrival (DOA) estimation The smart antenna system estimates the direction of arrival of the signal, using techniq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coupon-eligible Converter Box
A coupon-eligible converter box (CECB) was a digital television adapter that met eligibility specifications for subsidy "coupons" from the United States government. The subsidy program was enacted to provide terrestrial television viewers with an affordable way to continue receiving free digital terrestrial television services after the nation's television service transitioned to digital transmission and analog transmissions ceased. The specification was developed by the National Telecommunications and Information Administration (NTIA), with input from the broadcast and consumer electronics industries as well as public interest groups. History Early proposals In March 2005, United States House Commerce Committee chairman Joe Barton of Texas said he would introduce a bill requiring the transition to digital television "sometime in the spring", saying he wanted analog broadcasting to end on December 31, 2006. Included in his plan was a $400–$500 million subsidy for conve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog Television
Analog television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness, colors and sound are represented by amplitude, instantaneous phase and frequency, phase and frequency of an analog signal. Analog signals vary over a continuous range of possible values which means that Noise (electronics), electronic noise and interference may be introduced. Thus with analog, a moderately weak signal becomes Noise (video), snowy and subject to interference. In contrast, picture quality from a digital television (DTV) signal remains good until the signal level drops below digital cliff, a threshold where reception is no longer possible or becomes intermittent. Analog television may be wireless (terrestrial television and satellite television) or can be distributed over a cable network as cable television. All broadcast television systems used analog signals before the arrival of DTV. Motivated by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Television
Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative advancement and represented the first significant evolution in television technology since color television in the 1950s. Modern digital television is transmitted in high-definition television (HDTV) with greater resolution than analog TV. It typically uses a widescreen aspect ratio (commonly 16:9) in contrast to the narrower format of analog TV. It makes more economical use of scarce radio spectrum space; it can transmit up to seven channels in the same bandwidth as a single analog channel, and provides many new features that analog television cannot. A transition from analog to digital broadcasting began around 2000. Different digital television broadcasting standards have been adopted in different parts of the world; below are the more widel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cliff Effect
In telecommunications, the (digital) cliff effect or brickwall effect is a sudden loss of digital signal reception. Unlike analog signals, which gradually fade when signal strength decreases or electromagnetic interference or multipath increases, a digital signal provides data which is either perfect or non-existent at the receiving end. It is named for a graph of reception quality versus signal quality, where the digital signal "falls off a cliff" instead of having a gradual rolloff. This is an example of an EXIT chart. The phenomenon is primarily seen in broadcasting, where signal strength is liable to vary, rather than in recorded media, which generally have a good signal. However, it may be seen in significantly damaged media, which is at the edge of readability. The term is also used in economics for an unrelated phenomenon. Broadcasting Digital television This effect can most easily be seen on digital television, including both satellite TV and over-the-air terrestria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse-width Modulation
Pulse-width modulation (PWM), or pulse-duration modulation (PDM), is a method of reducing the average power delivered by an electrical signal, by effectively chopping it up into discrete parts. The average value of voltage (and current) fed to the load is controlled by turning the switch between supply and load on and off at a fast rate. The longer the switch is on compared to the off periods, the higher the total power supplied to the load. Along with maximum power point tracking (MPPT), it is one of the primary methods of reducing the output of solar panels to that which can be utilized by a battery. PWM is particularly suited for running inertial loads such as motors, which are not as easily affected by this discrete switching, because their inertia causes them to react slowly. The PWM switching frequency has to be high enough not to affect the load, which is to say that the resultant waveform perceived by the load must be as smooth as possible. The rate (or frequency) a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
I²C
I2C (Inter-Integrated Circuit, ), alternatively known as I2C or IIC, is a synchronous, multi-controller/multi-target (master/slave), packet switched, single-ended, serial communication bus invented in 1982 by Philips Semiconductors. It is widely used for attaching lower-speed peripheral ICs to processors and microcontrollers in short-distance, intra-board communication. Several competitors, such as Siemens, NEC, Texas Instruments, STMicroelectronics, Motorola, Nordic Semiconductor and Intersil, have introduced compatible I2C products to the market since the mid-1990s. System Management Bus (SMBus), defined by Intel in 1995, is a subset of I2C, defining a stricter usage. One purpose of SMBus is to promote robustness and interoperability. Accordingly, modern I2C systems incorporate some policies and rules from SMBus, sometimes supporting both I2C and SMBus, requiring only minimal reconfiguration either by commanding or output pin use. Applications I2C is appropriate for peri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Texas Instruments
Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globally. It is one of the top 10 semiconductor companies worldwide based on sales volume. The company's focus is on developing analog chips and embedded processors, which account for more than 80% of its revenue. TI also produces TI digital light processing technology and education technology products including calculators, microcontrollers, and multi-core processors. The company holds 45,000 patents worldwide as of 2016. Texas Instruments emerged in 1951 after a reorganization of Geophysical Service Incorporated, a company founded in 1930 that manufactured equipment for use in the seismic industry, as well as defense electronics. TI produced the world's first commercial silicon transistor in 1954, and the same year designed and manufactured t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Consumer Electronics Association
The Consumer Technology Association (CTA) is a standard and trade organization representing 1,376 consumer technology companies in the United States. CTA works to influence public policy, holds events such as the Consumer Electronics Show (CES) and CES Asia, conducts market research, and helps its members and regulators implement technical standards. CTA is led by president and CEO Gary J. Shapiro. Trade shows CES CES is a major technology trade show held each January in Las Vegas. The CTA-sponsored show typically hosts previews of products and new product announcements.First CES Goes Broadway in June 1967 , Bob Gerson, ''TWICE'', August 28, 2006 The first CES was held in 1967 in |
National Telecommunications And Information Administration
The National Telecommunications and Information Administration (NTIA) is an agency of the United States Department of Commerce that serves as the President's principal adviser on telecommunications policies pertaining to the United States' economic and technological advancement and to regulation of the telecommunications industry. Among its stated goals are: * Working to ensure that all Americans have affordable phone and cable TV service. * Helping to bring the benefits of advanced telecommunications technologies to millions of Americans in rural and underserved urban areas through its information infrastructure grants. * Providing the hardware that enables public radio and television broadcasters to extend and maintain the reach of their programming. * Advocating competition and liberalization of telecommunications policies around the world. * Participating in international government-to-government negotiations to open markets for U.S. companies. * Negotiating with foreig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DiSEqC
DiSEqC (; short for Digital Satellite Equipment Control) is a special communication protocol for use between a satellite receiver and a device such as a multi-dish switch or a small dish antenna rotor. DiSEqC was developed by European satellite provider Eutelsat, which now acts as the standards agency for the protocol. History Eutelsat apparently developed the system to allow satellite users in Continental Europe to switch between the more popular SES Astra satellites at 19.2° east and Eutelsat's own Hot Bird system at 13° east. As a result, the vast majority of European satellite receivers support DiSEqC 1.0 or higher, with the exception of all set top boxes manufactured under the Sky Digibox name. All supporting receivers have received certification to carry a logo specifying which variation of DiSEqC they support. Protocol DiSEqC relies only upon a coaxial cable to transmit both bidirectional data/signals and power. DiSEqC is commonly used to control switches and motors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USALS
Universal Satellites Automatic Location System (USALS), also known (unofficially) as ''DiSEqC 1.3'', ''Go X'' or ''Go to XX'' is a satellite dish motor protocol that automatically creates a list of available satellite positions in a motorised satellite dish setup. It is used in conjunction with the DiSEqC 1.2 protocol. It was developed by STAB, an Italian motor manufacturer, who still make the majority of USALS compatible motors. Software on the satellite receiver (or external positioner) calculates the position of all available satellites from an initial location (input by the user), which is the latitude and longitude relative to Earth. Calculated positions can differ ±0.1 degrees from the offset. This is adjusted automatically and does not require previous technical knowledge. Compared to DiSEqC 1.2, it is not necessary to manually search and store every known satellite position. Pointing to a known satellite position (for example 19.2ºE) is enough; this position will act as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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