DIGITAL COMMUNICATION SYSTEM USING SUPERPOSED TRANSMISSION OF HIGH SPEED AND LOW SPEED DIGITAL SIGNALS

摘要

A digital communication system using superposedtransmission of high and low speed digital signals capableof transmitting superposed high and low speed digitalsignals through an identical frequency band efficiently byincreasing a simultaneously transmittable number ofchannels in the low speed digital signals, while achievingthe practically reasonable bit error rate performances forboth the high speed digital signals and the low speeddigital signals. In this system, the low speed digitalsignals are transmitted in a form of spread spectrumsignals and the high speed digital signals are cancelledout from the superposed transmission signals in obtainingthe output low speed digital signals by using the phaseinverted replica of the high speed digital signals to becombined with the superposed transmission signals, so thatit becomes possible to increase a number of channels forthe low speed digital signals, while achieving thepractically reasonable bit error rate performances for boththe high speed digital signals and the low speed digitalsignals.