General Electric Company

Gregory N Mears

Arvid E Englund, Jr

Rodney A Dolman

A voltage controlled oscillator is provided with one or more varactors connected in series with the frequency determining capacitors of the oscillator. These varactors are in addition to prior art varactors, and increase the tunable range of the oscillator, and improve the frequency variation with control voltage characteristic of the oscillator.

Voltage controlled oscillator

An oscillator is controlled so that it produces the correct frequency in the transmitting condition, and so that it produces a slightly different frequency in the receiving condition. This is achieved by a circuit which supplies a first control voltage to the oscillator for transmitting and which supplies a second and different control voltage to the oscillator for receiving. This second and different control voltage causes the oscillator frequency in the receiving condition to be different so that there is no interference to or improper operation of a repeater system. The circuit also prevents any modulation signals from reaching the oscillator in the receiving condition, thus preventing false signals or other problems.

Oscillator control circuit

A combining and filter circuit is provided to connect the acquisition circuit and phase detector circuit to the voltage controlled oscillator in a phase locked loop. The combining and filter circuit includes twin-T filters for removing reference frequency signals. An output circuit includes series resistors and capacitors, and reverse poled Schottky diodes which provide rapidly changing acquisition signals that are relatively noise free.

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Forest, VA, United States of America

Gregory N Mears