Receiver tuning using variable capacitance diodes

This paper describes the design and performance of a remote tuned FM receiver. Three voltage variable capacitance diodes are used to tune the RF amplifier, local oscillator and mixer stages. Either local or remote tuning is accomplished by means of a variable DC bias voltage giving performance equal to receivers tuned by mechanical variable capacitors. Tracking and temperature stabilization methods are described along with advantages and disadvantages of this tuning method with respect to those presently used. Possible applications include central home music systems and aircraft receivers where it is desirable to separate the tuning control from the receiver.