Khalil E Massad

42914108, Sep 22, 1981

Oct 24, 1979

6/087910

Edgar L. Caples - Garland TX
Robert K. Marston - Plano TX
Khalil E. Massad - Richardson TX

Rockwell International Corporation - El Segundo CA

H04B 112
H04J 1300

375 1

A multipath diversity spread spectrum communications receiver will enhance system performance over communication channels with distortion caused by multipath and fading effects. The multipath diversity receiver utilizes decision directed coherent integration with post detection correlation techniques for performance enhancement. The receiver also incorporates a fast attack, fast release automatic gain control to process noncontinuous wideband spread spectrum signals which are subject to fading and multipath effects.

42530679, Feb 24, 1981

Dec 11, 1978

5/968069

Edgar L. Caples - Dallas TX
Robert K. Marston - Plano TX
Khalil E. Massad - Garland TX

Rockwell International Corporation - El Segundo CA

H04L 2722

329110

A radio signal is applied to an in phase detector channel and a quadrature phase detector channel. Each detector channel includes, in cascade arrangement; an in phase downconverter means for downconverting the received radio signal to a baseband signal; a sampling means for sampling the baseband signal at a predetermined rate; and a matched filter means matched to the symbol waveform and wherein the sample pulses are stored over a predetermined period of time that corresponds to two data symbols. The sum of the pulses for the first data symbol and the sum of the pulses for the second data symbol are compared to determine if there has been a phase reversal between the two data symbols. The outputs of the in phase and quadrature phase channels are summed, which results in demodulation of the encoded data.

42414512, Dec 23, 1980

Jun 26, 1978

5/919021

Richard C. Maixner - Dallas TX
Robert K. Marston - Plano TX
Khalil E. Massad - Garland TX

Rockwell International Corporation - El Segundo CA

H04B 126

455202

A single sideband signal can be demodulated by using sampled data techniques. An intermediate frequency (IF) radio signal is split into two branches and is sampled by two sample and hold devices; each sample and hold device operates at a rate that is not only a submultiple of the carrier frequency, but is also at least twice the information bandwidth. Prior to, or during sampling of one branch (the quadrature branch), a Hilbert's transform is performed upon the IF signal which results in the output of the two sample and hold devices being in phase quadrature. A phase shift of 90. degree. , using a baseband finite impulse response Hilbert's transform filter, is performed upon the output signal of the quadrature branch's sample and hold device. The sum of the inphase sampled signal and the filtered quadrature phase sampled signal produces the demodulated lower sideband while the difference between the two produces the demodulated upper sideband. There are two basic examples shown of single sideband demodulation through the use of sampled data techniques; in addition, there are several examples of implementing the Hilbert's Transformer.