Abstract: A variable data rate receiver is provided which employs a novel phase locked loop (PLL) of the type employing a data detection loop and a tracking loop. The data detection loop is initially not coupled to the input of the voltage controlled oscillator in the tracking loop of the PLL, but is separated by an electronic switch. A phase lock detection circuit is provided which is coupled to the data detection loop and to the tracking loop for detecting the difference in the voltage error signals in the data detection loop and the tracking loop. When this error signal indicates that the tracking loop is locked on to the carrier signal the electronic switch is closed completing the phase locked loop circuit after lock on of the carrier is achieved.

Abstract: In antenna arrays having normally unexcited or little-excited elements, a technique for configuring the array to provide both global and spot beam coverage, wherein the normally unexcited or little-excited elements are excited at a higher level, together with other normally excited elements to provide spot beam coverage, the normally unexcited elements being left unexcited to provide global beam coverage. Ring redundancy configurations for amplifiers in a transponder provided in the configuration are optimized to minimize additional hardware requirements. The specific example of the INMARSAT II satellite system is discussed.

Abstract: An electronic blanking system having a plurality of inputs from a number of radio frequency transmitters and a plurality of outputs for supplying blanking pulses to receivers which are in proximity to the transmitters includes input circuitry for processing input pulses from the inputs to produce processed input signals. Timers alter the timing of the processed input signals as required to produce the needed blanking pulses. Matrix means are provided for routing each blanking pulse to the outputs. A processor controls each matrix to determine the routing. Output drivers supply the blanking pulses, at predetermined voltage levels, to the outputs. The processor also controls the timers to determine the manner in which the timing is altered. The timers includes at least one of a delay for delaying the processed input signals, a stretching circuit for increasing the length of the processed input signals, and a truncator for truncating the length of the processed input signals.

Abstract: An improved threshold circuit (30) for reconstructing digitally-encoded, optically-transmitted signals is disclosed. The threshold circuit (30) automatically compensates for amplitude variations in the received signal due to noise, gain variations, and the like, and thereby provides improved accuracy in reproduction of the digitally-encoded signal. An amplifier (120) generates an output signal the level of which, under low signal amplitude, is linearly related to the instantaneous level of the digitally-encoded input signal. An active low pass linear filter (122, 124, 132) generates from the amplified output signal a signal the level of which corresponds to the average level of the amplified output signal. A bias signal generator (40) receives the average level signal on one input and a selected reference signal on the other.

Abstract: A three way oscillator signal power splitting circuit splits power provided at the output of a voltage controlled oscillator (VCO). The circuit is implemented on a printed circuit board section having a first layer which includes a first conductor for receiving the power from the VCO, a second layer having a second conductor, substantially parallel to and adjacent the first conductor, for receiving a portion of the power on the first main conductor via broadside coupling, and a third conductor, situated substantially parallel to and adjacent the first and second conductors, for receiving a portion of the power on the first main conductor also via broadside coupling. A ground conductor is additionally included on the third layer for providing a ground reference for the first, second and third conductors, and resistors are used to terminate the second and third conductors.