Abstract: An electronic structure includes an electronic device, and a heat sink assembly in thermal contact with the electronic device. The heat sink assembly is formed of a piece of pyrolytic graphite embedded within a metallic casing and intimately contacting an interior wall of the metallic casing. The heat sink assembly is substantially fully dense. The heat sink assembly is fabricated by assembling the piece of pyrolytic graphite within the disassembled elements of the metallic casing, and then simultaneously heating and pressing the initial assembly until it is substantially fully dense.

Abstract: Disclosed is a single phase-locked loop (50, 350) providing tuning over a very large bandwidth for use in wide band carrier tracking and clock recovery systems. In a first embodiment, a DC signal is formed representative of a phase difference between an input signal changing with time and a return signal. The DC signal is applied to a narrow band voltage controlled oscillator (68) which converts the DC signal back to an AC signal. The AC signal is level shifted to form a clocking pulse for an accumulator (80) of a direct digital synthesizer (72). A digital command word is also applied to tyhe accumulator (80), such that the digital command word represents a coarse tuning of the input frequency. The clocking pulse from the narrow band VCO (68) supplies a fine tuning of the input frequency.

Abstract: Disclosed is a single phase-locked loop (50, 350) providing tuning over a very large bandwidth for use in wide band carrier tracking and clock recovery systems. In a first embodiment, a DC signal is formed representative of a phase difference between an input signal changing with time and a return signal. The DC signal is applied to a narrow band voltage controlled oscillator (68) which converts the DC signal back to an AC signal. The AC signal is level shifted to form a clocking pulse for an accumulator (80) of a direct digital synthesizer (72). A digital command word is also applied to the accumulator (80), such that the digital command word represents a coarse tuning of the input frequency. The clocking pulse from the narrow band VCO (68) supplies a fine tuning of the input frequency. In a second embodiment, the DC representative phase signal is applied to an analog-to-digital converter (364) which produces an N-bit word representative of the phase difference.

Abstract: A variable phase shifter and amplitude weighting (VPSAW) device capable of selectively varying the phase and amplitude of an incoming RF signal (RF.sub.IN) in such a manner as to produce an output RF signal (RF.sub.OUT) having a selected phase and amplitude, by means of splitting the RF.sub.IN signal into first and second signal components, selectively shifting the phase of each of these two components, and then combining the thusly selectively phase-shifted first and second signal components. In the presently contemplated best mode of the present invention, the VPSAW device includes digitally-implemented componentry, e.g., microprocessor-controlled direct, digital synthesizers, for generating first and second control signals, e.g., selectively phase-shifted sinusoidal signals, indicative of first and second phase shift increments, .phi..sub.a and .phi..sub.b, respectively, to be imparted to the first and second signal components, respectively.

Abstract: A sine output or phase interpolation direct digital synthesizer for use in satellite programs having a random or pseudorandom code generator for summing a random digital word whose value ranges from zero to just under the least significant bit of a digital-to-analog converter with the current register value normally sent to the converter for reducing the spurious sidebands associated with the finite resolution of the converter within the synthesizer, the sum being truncated to the resolution of the converter and for controlling the converter, the spurious sidebands being reduced by randomization of the periodic behavior associated with the truncation process while lowering the total phase noise.

Abstract: The tuner section of a communications receiver 10 includes a gallium arsenide voltage controlled oscillator 48 for upconverting the received signal in mixer 18. Phase noise and post tuning drift associated with oscillator 48 is impressed onto the signal supplied by a second oscillator network 46. Thus, the outputs of mixers 18 and 78 both contain noise and post tuning drift associated with the gallium arsenide oscillator 48. Mixer 28 is used to substract the noise and drift component on line 30 from that on line 32 to thereby provide an output 14 which is substantially free of the noise and drift associated with the efficient, but noisy gallium arsenide VCO 48.