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1. (WO2001003440) METHOD AND APPARATUS FOR GENERATING MULTIPLE INDEPENDENT QAM CHANNELS

Pub. No.:    WO/2001/003440    International Application No.:    PCT/US2000/008679
Publication Date: Fri Jan 12 00:59:59 CET 2001 International Filing Date: Tue Apr 04 01:59:59 CEST 2000
IPC: H04L 5/06
H04N 7/24
Applicants: GENERAL INSTRUMENT CORPORATION
Inventors: KOLBER, Mark
OVADIA, Shlomo
Title: METHOD AND APPARATUS FOR GENERATING MULTIPLE INDEPENDENT QAM CHANNELS
Abstract:
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.