Abstract: A selection circuit for series connection between the output of the detector stage and the input of the audio amplifier. The selection circuit requires a minimum number of components and is useful to drive a tuning indicator or similar type circuit.

Abstract: A scanning radio receiver that is electronically tuned for station selectivity over a given band of frequencies. Varactor diodes contained in the RF and local oscillator stages of the scanning receiver circuitry are voltage controlled to select a finite number of different station frequencies within said given frequency band. A scan control circuit composed of several sections each including a potentiometer applies discrete d.c. voltages corresponding to the selected station frequencies to said varactor diodes. Digital means are employed to sequentially actuate the scan control circuit sections under the control of a received signal.