A spread spectrum communications systems utilizing an umbrella code.

Abstract

A pulse stuffing technique is used to eliminate the silent gaps in the transmission of a particular Spread Spectrum system. Unauthorized listeners now have more difficulty in recovering the message content. A two code device was built using both a pseudorandom maximal length code and a Golay complementary sequence code. The pseudorandom code was used for pulse stuffing an umbrella code and was discarded after a digital matched filter in the receiver. The Golay code was added with a Surface Acoustic Wave dispersive element and removed with a similar device used as a matched filter.