QAM (Quadrature Amplitude Modulation) is the format most cable companies use to send their digital cable signals over their network. Many new televisions include a built in tuner for QAM so that users are not require to have a set top box in order to receive digital cable. However, most content sent by the cable company is scrambled, with the exception of some local channels. Which channels are scrambled is subject to change and varies by cable company and geographic location. Most consumers will still need a set top box to unscramble the digital cable signal to receive most cable channels.
QAM tuners are similar to the ATSC tuners that receive HDTV content over the airwaves. The FCC does not require QAM tuners to be included like ATSC tuners. However, many television manufacturers are including both types of tuner.Related Articles