METHOD AND APPARATUS FOR GENERATING MULTIPLE INDEPENDENT QAM CHANNELS

摘要

A method and apparatus allow the combination of IF QAM signals for two or more different channels in a cable television system so that the resulting composite signal can be upconverted to an RF frequency by a single upconversion circuit for broadcast. The result saves both expense and space at the signal headend. A QAM modulator for each channel modulates the video signal for that channel to a different IF carrier frequency than other modulators in the system. The output of the modulators is further processed and then combined to generate an IF composite signal for multiple QAM channels that can be upconverted to RF for broadcast by a single upconverter.