General Electric Company

Earnest A Franke

Wayne J Faulkenberry

Frederick J Highton

A wide range reflective phase shifter/modulator including a 3dB hybrid splitter having ports A, B, C and D. An input signal to be phase modulated is applied to port-A and the phase modulator output signal is derived from port-C. Ports B and D are terminated with reactive circuits, which must be identical, including four variable reactive elements such as varactor diodes, the capacitance of which can be controlled by a modulating control voltage. By controlling the capacitance of the varactor diodes, the amount of phase shift in the signal derived from port-C is controlled. An alternative embodiment includes a circulator having ports E, F and G. An input signal to be phase modulated is applied to port-E and the phase modulator output signal is derived from port-G. Port-F is terminated with a reactive circuit, which includes two variable reactive elements such as varactor diodes, the capacitance of which can be controlled by a modulating control voltage. By controlling the capacitance of the varactor diodes, the amount of phase shift in the signal derived from port-G is controlled.

Wide range reflective phase shifter/modulator

Low power for a radio transmitter is indicated by an output power detector voltage falling below a low power reference voltage derived from an existing power control circuit.

Low power indicating circuit for a radio transmitter

Two printed circuit boards are connected together by a female coaxial connector, open at both ends, on one board, and by an elongated pin on the other board. When the boards are fastened together, the pin engages the female coaxial connector from one end. When the boards are separated, a male coaxial connector may engage the female coaxial connector from the other end.

Arrangement for connecting printed circuit boards

A radio transceiver has a single reference oscillator and a receiving frequency synthesizer and a transmitting frequency synthesizer. The synthesizer frequencies are selected so that the receiving intermediate frequency and a transmitting intermediate frequency (produced by the transmitted frequency mixing with the received frequency) are spaced widely apart. Thus, any beat note between the two intermediate frequencies is outside the passband or filter bandwidth in the receiver circuit.

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Goode, VA, United States of America

Earnest A Franke