In the disclosed digital circuit, a digital direct sequence modulation signal is converted to a suppressed clock pulse-duration modulation signal to thereby suppress the clock feature in the frequency spectra of a spread spectrum transmission system. The disclosed digital circuit includes a parallel...http://www.google.co.uk/patents/US4669089?utm_source=gb-gplus-sharePatent US4669089 - Suppressed clock pulse-duration modulator for direct sequence spread spectrum transmission systems
