Abstract: A receiver, especially useful for MMIC semiconductor communications circuits, in which plural mixers replace LRC filter networks to produce notched bandwidth filters. In a preferred embodiment, the input signal and a the output of a variable oscillator are mixed to produce a beat frequency. As an operator changes the desired frequency notch of the receiver, the output frequency of variable oscillator similarly changes to ensure that the beat frequency is the same regardless of desired frequency. Circuity downstream may be thus fixed, eliminating the need for large variable capacitors, which MMIC technology cannot fabricate in desirably small sizes.

Abstract: A heat-to-electricity converter, particularly adaptable for use by high-atude platforms such as aerostats and space stations, for changing heat energy of radiation from the earth to electric power during day and/or night. The converter includes an array of heat-collector sources and radiator heat sinks interconnected by thermoelectric n- and p- doped material elements. The array is fabricated on thin films of plastic and may be mounted on a high-altitude platform. The collectors absorb infrared (IR) heat from the earth and conduct the heat to the thermoelectric elements. The elements convert the heat to electricity. The absorbed heat less the heat converted to electricity is emitted to space by the radiator heat sinks.