Tuner (radio)
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A tuner is a subsystem that receives
More complex transmissions like
A tuner can also refer to a
Design
The simplest tuner consists of an
Older models would realize manual tuning by means of mechanically operated ganged variable capacitors. Often several sections would be provided on a tuning capacitor, to tune several stages of the receiver in tandem, or to allow switching between different frequency bands. A later method used a
Modern radio tuners use a
In a self-contained radio receiver for audio, the signal from the detector after the tuner is run through a volume control and to an amplifier stage. The amplifier feeds either an internal speaker or headphones. In a tuner component of an audio system (for example, a home high-fidelity system or a public address system in a building), the output of the detector is connected to a separate external system of amplifiers and speakers.
The broadcast audio FM band (88 - 108 MHz in most countries) is around 100 times higher in frequency than the AM band and provides enough space for a bandwidth of 50 kHz. This bandwidth is sufficient to transmit both stereo channels with almost the full
AM/FM tuners
Standalone audio stereo FM tuners are sought after for
Most of the early tuner models were designed and manufactured to receive only the AM broadcast band. As FM became more popular, the limitations of AM became more apparent, and FM became the primary listening focus, especially for stereo and music broadcasting. [citation needed]
The McIntosh MR78 is known as one of the first FM tuners precise enough to tune into a weaker station broadcast on the same frequency as another stronger signal. [3]
In Europe, where a second AM broadcast band is used for longwave broadcasting, tuners may be fitted with both the standard medium wave and the additional longwave band. However, radios with only medium wave are also common, especially in countries where there are no longwave broadcasters. Rarely, radios are sold with only FM and longwave, but no medium wave band. Some tuners may also be equipped with one or more short wave bands.
Television
A television tuner converts a
Before the use of solid-state frequency synthesizers, covering the broad range of TV signal frequencies with a single tuned circuit and sufficient precision was uneconomic. Television channel frequencies were non-contiguous, with many non-broadcast services interleaved between VHF channels 6 and 7 in North America, for example. Instead, TV tuners of the era incorporated multiple sets of tuned circuits for the main signal path and local oscillator circuit. These "turret" tuners mechanically switched the receiving circuits by rotating a knob to select the desired channel. Channels were presented in fixed sequence, with no means to skip channels unused in a particular area. When UHF TV broadcasting was made available, often two complete separate tuner stages were used, with separate tuning knobs for selection of VHF band and UHF band channels. To allow for a small amount of drift or misalignment of the tuner with the actual transmitted frequency, tuners of that era included a "fine tuning" knob to allow minor adjustment for best reception. The combination of high frequencies, multiple electrical contacts, and frequent changing of channels in the tuner made it a high maintenance part of the television receiver, as relatively small electrical or mechanical problems with the tuner would make the set unusable.
Analog tuners can tune only
Electronic tuner
An electronic tuner is a device which tunes across a part of the radio frequency spectrum by the application of a voltage or appropriate digital code words. This type of tuner supersedes mechanical tuners, which were tuned by manual adjustment of capacitance or inductance in the tuned circuits. In a more practical and everyday sense, a radio or television set which is tuned by manually turning a knob or dial contains a manual tuner into which the shaft of that knob or dial extends.
Early model televisions and radios were tuned by a rack of buttons; some of the earlier types were purely mechanical and adjusted the capacitance or inductance of the tuned circuit to a preset number of positions corresponding to the frequencies of popular local stations. Later electronic types used the
Modern electronic tuners also use varactor diodes as the actual tuning elements, but the voltages which change their capacitance are obtained from a
See also
- Analog passthrough
- ATSC tuner
- Bandspread
- Cable converter box
- Digital television adapter (DTA)
- Mini PC
- Minimum detectable signal
- Network TV Tuner
- QAM tuner
- Radio antenna
- Receiver (radio)
- Set-top box
- Television antenna
- Television set
- TV tuner card
References
- ^ "Stereo Gear in the 1970's Was it The Audiophile Golden Age?". Audioholics Home Theater, HDTV, Receivers, Speakers, Blu-ray Reviews and News. 8 November 2021. Retrieved 2022-08-15.
- ^ amfmdx.net - FM Tuner Mods Archived 2008-03-24 at the Wayback Machine
- ^ "The Consumer Electronics Hall of Fame: McIntosh MR 78 Tuner". IEEE Spectrum. 2019-10-24. Retrieved 2022-08-15.
- ^ a b c ivtvdriver.org - FM1216ME (MK3 family). Multi-Standard Desktop Video & FM, Radio Module, 2001-10-18
External links
- Media related to Tuner (radio) at Wikimedia Commons
- FM Tuner Information Center
- World Radio History