However, when used in the context of US digital cable television, the format of the data transmitted using this modulation is based on ITU-T J.83 Annex B ("J.83b").
This is in contrast to DVB-C which is also based on QAM modulation, but uses a DVB-based data format which is incompatible with North American receivers.
QAM is a parallel form of modulation that transmits two independent signals at a symbol rate that is near, but less than, the bandwidth of 6 MHz.
[4] The FCC mandates that all new TVs sold in the US must include an ATSC tuner, but there are no requirements for QAM tuning functionality.
[5] However, as of 2017, there is a trend towards large screen flat panel displays that don't include any kind of tuner, often referred to as "Tuner-Free TVs" or “Tunerless Displays.”[6][7] ClearQAM (unencrypted) lets cable subscribers avoid industry-provided set-top boxes (necessary for decoding encrypted basic cable signals).