Multiplexer for adjacent NTSC and DTV channels

摘要

A signal mutiplexer that combines the NTSC and DTV signals of adjacent television channels into a composite signal for transmission on a common transmission line or wave guide. Separate hybrid couplers and band pass filters produce quadrature phase signals that are combined in a signal combiner to produce a pair of quadrature phase multiplexed signals. A notch filter reflects the aural component of the NTSC signal. An output hybrid coupler combines the pair of multiplexed quadrature phase signals with the reflected aural component to produce the composite signal.