Single sideband coding privacy equipment - carrier and constitution frequencies are changed in programmed fashion

摘要

A privary coding system for the transmission of signals using carrier wave modulation and decoding at the receiver by means of a signal at the original carrier frequency. To ensure privacy use is made of more than one carrier frequency, the frequency of the carrier used at the transmitter and the reconstitution signal at the receiver being changed simultaneously. The transmitter and receiver may each be provided with sets of frequency dividers driven from a pair of HF oscillators on identical frequencies and the coding programme may connect different frequency dividers at different times. Particularly applicable to single sideband communication with mobile station.