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Analog passthrough is a feature found on some digital-to-analog television converter boxes. Boxes without the analog passthrough feature only allow older, analog-only TVs to view digital TV. Those with analog pass-through allow both digital and analog television to be viewed on older TVs.
Before digital television, passthrough originally existed in VCRs (and later PVRs and DVDRs) that connected to a TV set using RF connector, allowing the TV antenna or cable TV signal to be switched to pass through the VCR, or have VCR output added as an extra channel.
All digital-to-analog converter boxes have both an antenna input (which accepts the coaxial cable that formerly went directly to the TV) and an RF output (which now goes directly to the TV). They may also have additional outputs. Any converter box converts the digital signal for the current digital sub-channel to an analog signal (at the reduced screen resolution of the analog standard), outputs that signal onto analog channel 3 or 4 (set by the user to avoid any conflict with local over-the-air channels) and sends that signal to the analog tuner on the TV. With a box that lacks analog passthrough, no other signals are sent to the output, so all analog stations are lost.
In the US, this primarily affects low-power and broadcast translator stations, as these are exempt from the FCC mandate to switch to digital broadcasting in 2009, as well as foreign signals that will remain in analog form. A small number of TV receivers were also manufactured with built-in broadcast radio receivers; these included some small portable devices or (more rarely) sets marketed for hotel/motel use. If used with DTV converter boxes, these will need analog passthrough in order not to block incoming FM radio signals. [1]
Some converter boxes offer analog pass-through, meaning that the same output cable which carries the converted digital signal (on analog channel 3 or 4) while the converter is operating also retains all remaining analog signals upon turning the converter box off.
While this typically works to some extent with the converter box on, there is often significant signal strength reduction and/or interference on the original analog channels.
Analog pass-through signals are passed only to the coax output, not to any other outputs provided by the unit. While other converter outputs may still be connected and used for digital TV reception, the coaxial RF output must remain connected to pass analog TV signals.
Some VCRs and TVs have receivers that detect active composite video or S-video connections. When they detect these connections, they are designed to accept signals only from those sources, which can cause issues with the described arrangement. In such a case, the two options would be to use the coax output exclusively, either when viewing analog TV only (which requires plugging and unplugging cables) or full-time (with the reduced digital TV quality produced using the coax output).
The majority of TVs have a button on the unit and/or remote labeled something like "TV/VIDEO", "INPUT" or "AUX", which manually switches between coax and other sources. This eliminates problems when using both sets of connections simultaneously.
This section may contain information not important or relevant to the article's subject.(September 2022) |
In the US, conversion to digital TV from analog was complete by June 12, 2009.
Unfortunately, only one of the initially available converter boxes included this feature,[ citation needed ] and a year before the original transition date of February 17, 2009, Community Broadcasters Association president Ron Bruno said four of the 32 NTIA-certified boxes had the feature. [2] In late March 2008, the CBA filed a lawsuit in the U.S. Court of Appeals for the District of Columbia, seeking an injunction to halt the sale and distribution of DTV converter boxes, [3] charging that their failure to include analog tuners or analog passthrough violates the All-Channel Receiver Act. [4] CBA maintained that the lack of analog support would seriously harm the LPTV and class A television stations the group represents, as it is cost-prohibitive for many or most of them to convert to digital transmissions, and the new boxes would prevent viewers from being able to watch (or even being aware of the existence of) their analog-only stations. [5] [6]
Responding to CBA's actions, the FCC and NTIA urged manufacturers to include the feature voluntarily in all converter boxes, and manufacturers responded by releasing a new generation of models with the feature. Some new DVD recorders and personal video recorders also provide both analog and digital tuners, and could therefore perform the basic functions of a set-top box in both modes.
In early May 2008, the D.C. district court denied the CBA petition without comment.[8] The court's decision implied that the association had not exhausted all its efforts. Furthermore, the court believed there wasn't enough merit to bring the case forward. The CBA responded by concentrating its lobbying efforts on the FCC and by urging more funding for low-power and Class A broadcasters to transition to digital, asking Congress to increase the number of such stations eligible for funds.
Cable television is a system of delivering television programming to consumers via radio frequency (RF) signals transmitted through coaxial cables, or in more recent systems, light pulses through fibre-optic cables. This contrasts with broadcast television, in which the television signal is transmitted over-the-air by radio waves and received by a television antenna, or satellite television, in which the television signal is transmitted over-the-air by radio waves from a communications satellite and received by a satellite dish on the roof. FM radio programming, high-speed Internet, telephone services, and similar non-television services may also be provided through these cables. Analog television was standard in the 20th century, but since the 2000s, cable systems have been upgraded to digital cable operation.
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 in contrast to the narrower format (4:3) 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 widely used standards:
A set-top box (STB), also known as a cable box, receiver, or simply box, and historically television decoder or a converter, is an information appliance device that generally contains a TV tuner input and displays output to a television set, turning the source signal into content in a form that can then be displayed on the television screen or other display device. It is designed to be placed alongside or "on top" of a television set.
An RF modulator is an electronic device used to convert signals from devices such as media players, VCRs and game consoles to a format that can be handled by a device designed to receive a modulated RF input, such as a radio or television receiver. Its input is a baseband signal, which is used to modulate a radio frequency source.
SCART is a French-originated standard and associated 21-pin connector for connecting audio-visual (AV) equipment. The name SCART comes from Syndicat des Constructeurs d'Appareils Radiorécepteurs et Téléviseurs, "Radio and Television Receiver Manufacturers' Association", the French organisation that created the connector in the mid-1970s. The related European standard EN 50049 was refined and published in 1978 by CENELEC, calling it péritelevision, but it is commonly called by the abbreviation péritel in French.
Composite video is an baseband analog video format that typically carries a 405, 525 or 625 line interlaced black and white or color signal, on a single channel, unlike the higher-quality S-Video and the even higher-quality YPbPr.
The All-Channel Receiver Act of 1962 (ACRA), commonly known as the All-Channels Act, was passed by the United States Congress in 1961, to allow the Federal Communications Commission to require that all television set manufacturers must include UHF tuners, so that new UHF-band TV stations could be received by the public. This was a problem at the time since most affiliated stations of the Big Three television networks were well-established on VHF, while many local-only stations on UHF were struggling for survival.
In electronics and radio, a tuner is a type of receiver subsystem that receives RF transmissions, such as AM or FM broadcasts, and converts the selected carrier frequency into a form suitable for further processing or output, such as to an amplifier or loudspeaker. A tuner is also a standalone home audio product, component, or device called an AM/FM tuner or a stereo tuner that is part of a hi-fi or stereo system, or a TV tuner for television broadcasts. The verb tuning in radio contexts means adjusting the receiver to detect the desired radio signal carrier frequency that a particular radio station uses. Tuners were a major consumer electronics product in the 20th century but in practice are often integrated into other products in the modern day, such as stereo or AV receivers or portable radios.
A DVD recorder is an optical disc recorder that uses optical disc recording technologies to digitally record analog or digital signals onto blank writable DVD media. Such devices are available as either installable drives for computers or as standalone components for use in television studios or home theater systems.
An ATSCtuner, often called an ATSC receiver or HDTV tuner, is a type of television tuner that allows reception of digital television (DTV) television channels that use ATSC standards, as transmitted by television stations in North America, parts of Central America, and South Korea. Such tuners are usually integrated into a television set, VCR, digital video recorder (DVR), or set-top box which provides audio/video output connectors of various types.
Single-cable distribution is a satellite TV technology that enables the delivery of broadcast programming to multiple users over a single coaxial cable, and eliminates the numerous cables required to support consumer electronics devices such as twin-tuner digital video recorders (DVRs) and high-end receivers.
A digital television adapter (DTA), commonly known as a converter box or decoder box, is a television tuner that receives a digital television (DTV) transmission, and converts the digital signal into an analog signal that can be received and displayed on an analog television set. Some also have an HDMI output since some TVs with HDMI do not have a digital tuner. The input digital signal may be over-the-air terrestrial television signals received by a television antenna, or signals from a digital cable system. It normally does not refer to satellite TV, which has always required a set-top box either to operate the big satellite dish, or to be the integrated receiver/decoder (IRD) in the case of direct-broadcast satellites (DBS).
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.
A DTV receiver is a set-top box that permits the reception of digital television. Its components are very similar to a desktop PC. The DTV receiver is a vital link in the chain of television system. The goal of a broadcasting system is to concentrate the hardware requirements at the source to simplify the receivers and makes it as inexpensive as possible.
Digital television in the United States is available via digital terrestrial television (DTT), digital cable, satellite television, and IPTV providers.
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.
A cable converter box or television converter box is an electronic tuning device that transposes/converts channels from a cable television service to an analog RF signal on a single channel, usually VHF channel 3 or 4, or to a different output for digital televisions such as HDMI.
The digital television transition in the United States was the switchover from analog to exclusively digital broadcasting of terrestrial television programming. Under the Digital Transition and Public Safety Act of 2005, full-power broadcasting of analog television in the United States was initially planned to have ceased after February 17, 2009, but this was delayed to June 12, 2009, after the passage of the DTV Delay Act on February 4, 2009. This date was a further delay from the original date of December 31, 2006, as stipulated in the Telecommunications Act of 1996. The delay to June 12 was to assist households on a waiting list for coupons for digital converter boxes, funding for which was provided by the American Recovery and Reinvestment Act of 2009.
The Community Broadcasters Association (CBA) was a trade organization representing low-power broadcasting interests, including LPTV and Class A television stations, in the United States of America. It ceased operations in 2009.
In broadcasting, a transposer or translator is a device in or beyond the service area of a radio or television station transmitter that rebroadcasts signals to receivers which can’t properly receive the signals of the transmitter because of a physical obstruction. A translator receives the signals of the transmitter and rebroadcasts the signals to the area of poor reception. Sometimes the translator is also called a relay transmitter, rebroadcast transmitter or transposer. Since translators are used to cover a small shadowed area, their output powers are usually lower than that of the radio or television station transmitters feeding them.
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