The Complete Handbook of TV Tuner Cards & Adapters

Chapter 1: Understanding TV Tuner Cards & Adapters

A TV tuner card or adapter is a piece of hardware that receives broadcast or cable television signals and converts them into digital data that a computer can process, store, or distribute. That simple definition masks considerable complexity. The hardware itself may be an internal card that plugs into a PCI or PCIe slot in a desktop computer, a USB device that connects to any computer with a USB port, or a networked appliance that streams tuned signals over Ethernet. The signals it receives may be analog television (largely obsolete in developed nations but still in use), over-the-air digital broadcasts in formats like ATSC (North America) or DVB-T (Europe and much of Asia), satellite television via DVB-S or DVB-S2, or cable television in QAM (quadrature amplitude modulation) format. A single tuner card may handle only one of these standards, or it may handle multiple. Understanding what a TV tuner actually does requires looking past the marketing and into what happens when a signal arrives at the antenna.

At the core, a TV tuner is a radio receiver specialized for television. When an antenna receives broadcast television signals—whether from a terrestrial transmitter, a satellite, or a cable distribution system—the signal is an electromagnetic wave carrying information across a specific frequency band. The tuner's job is to isolate the signal for the channel you want to watch, reject the signals for all other channels, amplify it to usable strength, and then demodulate it—that is,