Radio receiver operable in station search mode or station select mode

Abstract

A radio receiver comprising a local oscillator, a first counter circuit for computing an algebraic sum of a number corresponding to an oscillating frequency of the local oscillator and a number corresponding to an intermediate frequency, the algebraic sum representing frequency information for a tuned input signal frequency of the receiver, a memory circuit for storing frequency information produced by the counter when the receiver is tuned to a broadcast station in a station search mode, a digital comparator for comparing the frequency information read out of the memory circuit with the frequency information of the counter in a station select mode, and a charge pump and lowpass filter responsive to the digital comparator to control a local oscillator frequency of the local oscillator so that the frequency information of the counter becomes coincident with the frequency information from the memory circuit. A second counter is provided for counting clock pulses in the station search mode. The output signal of the second counter is compared with the output signal of the first counter by the digital comparator. The station frequency information read out of the memory circuit in the station select mode may be programmed in the second counter.