TV tuner

(1) The electronic circuit in an analog or digital TV that latches onto a TV channel and filters out the signals. See carrier and QAM.

(2) A plug-in card or USB module for a computer that tunes in over-the-air (OTA) or cable TV channels. Attaching to the antenna cable or the cable company's cable via a coaxial F connector, the tuner includes software to change the channel and render the video content on screen. The software may also be able to use the computer's hard disk as a digital video recorder (DVR). Tuners on PCI and PCIe cards also include A/V inputs for connection to external video sources.

In older PCs, TV tuner plug-in cards connected to the VGA card via an internal connector (see VGA feature connector).

An Audio Tuner

Not exactly a plug-in computer module, this 1925 battery-operated Stewart Warner Radio required listeners to tune three stages manually. When they got a good signal, they recorded the numbers on a log sheet (top) so they could tune in quickly the next time. (Equipment courtesy of Vintage Radio and Communications Museum of Connecticut, www.vrcmct.org)