Communications Satellite Corporation

Tsvi F Assal

Christoph E Mahle

Arnold L Berman

Richard C Mott

Robert T Kroll, Jr

A burst duration and guard space monitor circuit which produces burst duration and guards space signals which are substantially unaffected by nulls or near nulls in a received QPSK signal. The received QPSK signal is compared with a fixed threshold voltage. The comparison output is sampled at twice the symbol rate of the QPSK signal and the samples are first clocked into a three-bit burst duration shift register. The outputs of each of the cells of the burst duration shift register are OR'ed to produce the burst duration signal. The burst duration signal is inverted and then clocked into a four-bit guard space shift register, the outputs of which are OR'ed to produce the guard space signal. A clock signal is produced for operating the flip-flops, burst duration shift register and guard space shift register which has a frequency of twice the clock frequency of the QPSK signal. This clock signal is adjusted in phase so that the sampling times of the detected QPSK signal occur at times removed from nulls or near nulls therein.

Satellite-receiver time division multiple-access burst duration and

A temperature-compensated microwave integrated circuit device such as a delay line in which the phase delay imparted to signals coupled through the delay line is substantially constant over a wide range of temperatures. A dielectric substrate is provided, with strip conductors on one surface defining a desired device configuration such as a multi-pole Butterworth filter configuration. The substrate is enclosed within a support frame with the lower side of the substrate positioned upon the bottom surface of the enclosure forming a ground plane. A conductive plate is attached to the top cover of the enclosure through a layer of compensating material. As the temperature changes, the layer of compensating material expands or contracts, thereby varying the height of the conductive plate above the substrate, which changes the electromagnetic field pattern of signals propagating along the delay line and, consequently, the propagation velocity. The thickness and coefficient of expansion of the compensating layer are chosen to maintain the delay time through the device at a substantially constant value.

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Bethesda, MD, United States of America

Tsvi F Assal