Abstract: A suppressed carrier radio signaling system is described in which there is a servo loop utilizing balanced circuit techniques and using the carrier as the reference, in which a phase detector (or coherent demodulator) constantly senses the phase difference between the carrier source and the carrier component in the output signal to derive an error signal which is used to vary the amount of the carrier component toward zero.

Abstract: An angle modulation radio communications system having privacy and security characteristics. The system utilizes two or more communication units, one at the transmitting terminal and the other at the receiving terminal of identical functional construction and each having a transceiver module, an antenna and a phase reversal modulator-demodulator module between the transceiver module and the antenna. Complex phase reversal modulation of the transmitted carrier is accomplished which produces a constant amplitude spread spectrum frequency-modulated carrier from which the modulation is not recoverable without a proper code in an autocorrelation process.

Abstract: A communication system comprising one or more communication units (transceivers) in which the transmitter includes means for modulating the carrier wave in such manner that the carrier amplitude is not varied by signal information but nevertheless signal information content can be extracted by conventional amplitude-modulation detection at the receiver. The signal power spectrum is varied along the frequency axis due to angle or phase modulation. The main components of each unit includes a transceiver, antenna and a phase-reversal modulator-correlator module between the antenna and the transceiver. The modulator-correlator module is bidirectional in operation and therefore it further modulates a spectrum of any signals from the transceiver which are radiated from the antenna and likewise modulates the spectrum of any electromagnetic wave signals received by the antenna.