TV radio

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Close-up view of the audio bands on a Sony ICF-36 portable radio, manufactured in 2001. The TV audio bands are obsolete and not usable with digital TV channels. Sony ICF-36 portable radio - tuner bands - weather tv fm am.JPG
Close-up view of the audio bands on a Sony ICF-36 portable radio, manufactured in 2001. The TV audio bands are obsolete and not usable with digital TV channels.
Overall view of portable radio Sony ICF-36 portable radio - overview.JPG
Overall view of portable radio

"TV radio", "TV band radio", "TV audio radio", "radio TV", "teleradio", "radiotelevision", "radiovision", "TVR", "RTV", "TR" and "RV" are common names for a type of radio receiver that can play the audio portion of a TV channel. The actual name of the device may comprise a list of all frequency bands the device can receive (e.g. AM, FM, weather, TV radio), one or two of which includes the TV channel bands.

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Analog tuning of analog TV audio

For the increasingly uncommon analog television standard, the audio for each TV channel is broadcast on a separate frequency band near the video signal frequency band (refer to article NTSC, Transmission modulation scheme). This audio signal can be heard separate from the video, using standard analog FM radios equipped with the appropriate tuning circuits.

Design issues for tuning of digital TV audio

After the relatively recent transition of many countries to digital TV, no radio receiver manufacturer has developed an alternative method to play just the audio portion of digital TV channels. [1] (DTV radio is not the same thing but in fact the opposite. The radio signal goes to the television receiver as opposed to the TV audio signal going to the radio receiver.)

DTV broadcasters can broadcast multiple separate video programs over one channel frequency in a digital subchannel, so it is necessary for a portable radio equipped with a digital audio decoder to do more than simply tune in to the frequency as with older analog receivers. It also needs to provide a way for the listener to choose among these digital subchannels, usually labeled as *.1, *.2, *.3, etc., on digital televisions with ATSC tuners. This is possible using an analog tuning dial to tune in to a digital TV broadcast, coupled with a button to select the digital subchannel.

Direct analog frequency tuning of digital TV is further complicated by the fact that digital TV broadcasting allows the use of virtual channel numbers that are separate from the actual broadcast frequency channel. In this manner, on a fully digital receiver, a station may appear to be on VHF channel 13 but actually broadcasts on UHF channel 33. This complexity is hidden from the users of fully digital receivers, but would be exposed to the user of an analog tuner with a subchannel selector.

A fully digital tuning system can hide these complexities from the user, but typically a digital tuner has to perform a special channel scan function to find available digital broadcasts. For a person traveling long distances with a digitally tuned digital TV audio radio, it would be necessary to periodically rescan the available channels to find new stations.

Related Research Articles

<span class="mw-page-title-main">Analog television</span> Television that uses analog signals

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, phase and frequency of an analog signal.

<span class="mw-page-title-main">Digital television</span> Television transmission using digital encoding

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:

<span class="mw-page-title-main">Set-top box</span> Electronic device to convert a signal to an output for a television

A set-top box (STB), also colloquially known as a cable box or receiver and historically television decoder, is an information appliance device that generally contains a TV-tuner input and displays output to a television set and an external source of signal, turning the source signal into content in a form that can then be displayed on the television screen or other display device. They are used in cable television, satellite television, and over-the-air television systems as well as other uses.

A subcarrier is a sideband of a radio frequency carrier wave, which is modulated to send additional information. Examples include the provision of colour in a black and white television system or the provision of stereo in a monophonic radio broadcast. There is no physical difference between a carrier and a subcarrier; the "sub" implies that it has been derived from a carrier, which has been amplitude modulated by a steady signal and has a constant frequency relation to it.

Digital radio is the use of digital technology to transmit or receive across the radio spectrum. Digital transmission by radio waves includes digital broadcasting, and especially digital audio radio services.

Multichannel Television Sound, better known as MTS, is the method of encoding three additional audio channels into analog 4.5 MHz audio carriers on System M and System N. It was developed by the Broadcast Television Systems Committee, an industry group, and sometimes known as BTSC as a result.

<span class="mw-page-title-main">Amateur television</span>

Amateur television (ATV) is the transmission of broadcast quality video and audio over the wide range of frequencies of radio waves allocated for radio amateur (Ham) use. ATV is used for non-commercial experimentation, pleasure, and public service events. Ham TV stations were on the air in many cities before commercial television stations came on the air. Various transmission standards are used, these include the broadcast transmission standards of NTSC in North America and Japan, and PAL or SECAM elsewhere, utilizing the full refresh rates of those standards. ATV includes the study of building of such transmitters and receivers, and the study of radio propagation of signals travelling between transmitting and receiving stations.

<span class="mw-page-title-main">All-Channel Receiver Act</span> United States legislation

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.

<span class="mw-page-title-main">Tuner (radio)</span>

A tuner is a subsystem that receives radio frequency (RF) transmissions, such as FM broadcasting, and converts the selected carrier frequency and its associated bandwidth into a fixed frequency that is suitable for further processing, usually because a lower frequency is used on the output. Broadcast FM/AM transmissions usually feed this intermediate frequency (IF) directly into a demodulator that converts the radio signal into audio-frequency signals that can be fed into an amplifier to drive a loudspeaker.

<span class="mw-page-title-main">HD Radio</span> Digital radio broadcast technology

HD Radio (HDR) is a trademark for an in-band on-channel (IBOC) digital radio broadcast technology. HD radio generally simulcasts an existing analog radio station in digital format with less noise and with additional text information. HD Radio is used primarily by AM and FM radio stations in the United States, U.S. Virgin Islands, Canada, Mexico and the Philippines, with a few implementations outside North America.

A television transmitter is a transmitter that is used for terrestrial (over-the-air) television broadcasting. It is an electronic device that radiates radio waves that carry a video signal representing moving images, along with a synchronized audio channel, which is received by television receivers belonging to a public audience, which display the image on a screen. A television transmitter, together with the broadcast studio which originates the content, is called a television station. Television transmitters must be licensed by governments, and are restricted to a certain frequency channel and power level. They transmit on frequency channels in the VHF and UHF bands. Since radio waves of these frequencies travel by line of sight, they are limited by the horizon to reception distances of 40–60 miles depending on the height of transmitter station.

<span class="mw-page-title-main">ATSC tuner</span> Tuner for digital television channels

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.

In broadcasting, digital subchannels are a method of transmitting more than one independent program stream simultaneously from the same digital radio or television station on the same radio frequency channel. This is done by using data compression techniques to reduce the size of each individual program stream, and multiplexing to combine them into a single signal. The practice is sometimes called "multicasting".

A digital channel election was the process by which television stations in the United States chose which physical radio-frequency TV channel they would permanently use after the analog shutdown in 2009. The process was managed and mandated by the Federal Communications Commission for all full-power TV stations. Low-powered television (LPTV) stations are going through a somewhat different process, and are also allowed to flash-cut to digital.

<span class="mw-page-title-main">DTV receiver</span>

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.

<span class="mw-page-title-main">Broadcast relay station</span> Repeater transmitter

A broadcast relay station, also known as a satellite station, relay transmitter, broadcast translator (U.S.), re-broadcaster (Canada), repeater or complementary station (Mexico), is a broadcast transmitter which repeats the signal of a radio or television station to an area not covered by the originating station. It expands the broadcast range of a television or radio station beyond the primary signal's original coverage or improves service in the original coverage area. The stations may be used to create a single-frequency network. They may also be used by an AM or FM radio station to establish a presence on the other band.

Digital television in the United States is available via digital terrestrial television (DTT), digital cable, satellite television, and IPTV providers.

Analog passthrough is a feature found on some digital-to-analog television converter boxes. Boxes without analog passthrough only allow digital TV to be viewed on older, analog-only TVs. Those with analog passthrough allow both digital and analog television to be viewed on older TVs.

The digital transition in the United States was the switchover from analog to exclusively digital broadcasting of terrestrial television programming. According to David Rehr, then president and CEO of the National Association of Broadcasters, this transition represented "the most significant advancement of television technology since color TV was introduced." For full-power TV stations, the transition went into effect on June 12, 2009, with stations ending regular programming on their analog signals no later than 11:59 p.m. local time that day.

This is a list of low-power television stations (LPTV) in the United States, transmitting on VHF channel 6, which also operate as radio stations capable of being picked up by many standard FM receivers. These stations are colloquially known as "Franken FMs", a reference to Frankenstein's monster, because TV stations functioning as radio stations had not been envisioned by the Federal Communications Commission (FCC). The FCC commonly refers to these stations as "FM6" operations. All of these FM transmissions are authorized for operation on a center frequency of 87.75 MHz.

References

  1. Will TV Band Radios Work with Digital TV?, From Matthew Torres, former About.com Guide http://tv.about.com/od/hdtv/f/tvbandradio.htm