Walter Ewanus

43510647, Sep 21, 1982

Jan 31, 1973

5/328213

Walter Ewanus - Ellicott City MD

Westinghouse Electric Corp. - Pittsburgh PA

H04B 110
H04K 100

455 29

There is disclosed frequency modulation (FM) or phase modulation (PM) communication with a receiver having a limiter, in spread-spectrum operation for security purposes. The spectrum is spread on transmission by superimposing a psuedo-noise code modulation on the intelligence modulation of the carrier. On reception the spectrum is collapsed by auto-correlation of the pseudo-noise code. The pseudo-noise spectrum is produced by a digital coder which causes phase modulation of the carrier at the transmitter and the spectrum is collapsed by an identical coder which remodulates the received signal at the receiver which is operated in precise synchronism with the coder at the transmitter. To maintain synchronism a reference oscillator signal which periodically varies the phase of the received carrier is injected into the coder network at the receiver; this reference oscillator signal is processsed so that it passes through the limiter of the receiver. The modulated carrier from the transmitter is received in parallel paths.

41852419, Jan 22, 1980

Jun 6, 1973

5/367659

Walter Ewanus - Ellicott City MD
George A. McKay - Laurel MD

Westinghouse Electric Corp. - Pittsburgh PA

H04B 700
H04K 100

325 47

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. The modulator-correlator module is bidirectional in operation, and because of its interposition between the antenna and the receiver module, the modulator-correlator spreads the spectrum of any electromagnetic wave signals supplied by it to the transmitting antenna and also spreads the spectrum of any signals received by the antenna not included in accordance with the proper code. Therefore, the units of the system present a very high degree of signal frequency selectivity and rejection of any electromagnetic wave radiation not having the proper code. Pseudo-random code phase reversal modulation suppresses the carrier and the intelligence signal power is in the form of frequency perturbations of the pseudo noise code modulation.

41123689, Sep 5, 1978

Jul 13, 1970

5/054259

Walter Ewanus - Ellicott City MD
Gerald F. Sage - Grand Rapids MI

Westinghouse Electric Corp. - Pittsburgh PA

H04K 100

325 32

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. The modulation performed in the receive mode is of such a form that the signal is transformed into conventional amplitude modulated carrier which can be demodulated by a normal narrow band receiver. The modulation performed at the receiver is a correlation process so that an intended receiver can be discretely addressed through a coding process.

42075254, Jun 10, 1980

Feb 14, 1977

5/768131

Robert J. Martel - Baltimore MD
Walter Ewanus - Ellicott City MD

Westinghouse Electric Corp. - Pittsburgh PA

H04B 168

455109

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.