TV double image?

While typically a PCI-bus expansion card, they can also be a USB device. Some video cards double as TV tuners, notably the ATI All-In-Wonder series. The card contains a receiver, tuner, demodulator, and a analog-to-digital converter for analog TV. Like TV sets, each version is designed for the radio frequencies and video formats used in each country. However, many TV tuners used in computers use DSP, so a firmware upgrade is often all that's necessary to change the supported video format. Many newer TV tuners have flash memory big enough to hold the firmwares for decoding several different video formats, making it possible to use the tuner in many countries without having to flash the firmware. In addition to the frequency tuner, many include a composite video input. Many TV tuners can function as FM radios: this is because the FM radio spectrum lies between television channels 6 and 7, and the DSP can be easily programmed to decode FM.