Abstract: A phase locked loop utilizing digital techniques to control the closed loop bandwidth of the RF carrier phase locked loop in a receiver provides high sensitivity and a wide dynamic range for signal reception. After analog to digital conversion, a digital phase locked loop bandwidth controller provides phase error detection with automatic RF carrier closed loop tracking bandwidth control to accommodate several modes of transmission.

Abstract: A secure communications system multiplexes segments of the information signal for keyed encoding and modulation onto a plurality of different carrier frequencies and/or polarizations, and transmits the encoded carriers to multi-channel signal summing receivers that decode the segments from all channels, to reassemble the information signal for use by authorized stations with a key. The use of the multi-channel link and the summing receiver allows the greatest number of different coding algorithms for accommodating the greatest number of discrete secure channels.

Abstract: A receiver utilizing a plurality of small paraboloid antennas in lieu of a single large antenna of equal area, each antenna connected to a separate phase coherent heterodyne receiver channel includes a main channel and branch channels, the channels being summed to provide a carrier phase locked loop local oscillator signal that is distributed to all channels producing phase coherent IF signals in all the channels. These are summed to enhance the carrier margin or dB from the sensitivity threshold, of the system combining the receiver channels, to a level greater than that of the single antenna of equivalent area with its single receiver. The tendency toward cycle slipping near threshold is further reduced by providing summed additional amplified uncorrelated predetection receiver noise in the IFs of the branch receiver coupled to the main receiver.

Abstract: A method and apparatus for measuring Faraday rotation of a received rf signal. The disclosure describes a specific implementation of a simultaneous orthogonal polarization receiver which compensates for a 3 db loss due to splitting of a received signal into left circular and right circular polarization channels. The compensation is achieved by rf and modulation arraying utilizing a specific receiver array which also detects and measures Faraday rotation in the presence or absence of spin stabilization effects on a linear polarization vector. Either up-link or down-link measurement of Faraday rotation is possible utilizing the method and apparatus disclosed herein.

Abstract: A method and apparatus for increasing the signal-to-noise ratio of a receiving facility for coherent frequency reception by arraying receiving systems using separate antennas for each, or one antenna for all systems. One system is operated with a carrier tracking loop to provide a first local oscillator frequency for the first and all other systems arrayed, with individual tracking loops in all other systems operated at IF for tracking out any phase differences due to separate group delays using an adjustable phase shifter for a second reference (REF. 2) to compensate for different group delays in the antenna and low-noise amplifier of each of the other systems. The second IF output of all systems are summed into the first system.