Abstract: A superheterodyne receiver of a scanning type, comprising a high frequency amplifier, a mixer, a local oscillator, an interdmediate frequency amplifier, a detector, an audio frequency amplifier, a loud speaker, and an automatic scanning/manual scanning selecting switch, said local oscillator comprising a digital frequency synthesizer comprising a voltage controlled oscillator, a programmable frequency divider for dividing the frequency of the output from the voltage controlled oscillator, a reference oscillator, a random access memory for storing the information concerning the rate of the frequency division by the frequency divider, and a phase detector for phase detecting the frequencies of the outputs from the reference oscillator and the frequency divider for providing a control voltage to said voltage controlled oscillator, said receiver further comprising an astable multivibrator for generating pulses for scanning the frequencies of the receiving bands, a counter for counting the pulses from the astable

Abstract: A superheterodyne receiver includes a first mixer operative to provide reception on a nonpriority channel upon receipt of output signal from a first oscillator, a second mixer operative to provide reception on a priority channel upon receipt of output signal from a second oscillator. A switching system coupled with a pulse generator is connected to the first and second oscillators for alternately operating the first and second mixers. When the receiver receives the priority channel through the second mixer, the pulse generator is locked to inhibit the generation of pulses which would enable the first oscillator and mixer and to continually receive the priority channel.

Abstract: A superheterodyne receiver of a scanning type, comprising a high frequency amplifier, a mixer, a local oscillator, an intermediate frequency amplifier, a detector, an audio frequency amplifier, a loud speaker, and an automatic scanning/manual scanning selecting switch, said local oscillator comprising a digital frequency synthesizer comprising a voltage controlled oscillator, a programmable frequency divider for dividing the frequency of the output from the voltage controlled oscillator, a reference oscillator, a random access memory for storing the information concerning the rate of the frequency division by the frequency divider, and a phase detector for phase detecting the frequencies of the outputs from the reference oscillator and the frequency divider for providing a control voltage to said voltage controlled oscillator, said receiver further comprising an astable multivibrator for generating pulses for scanning the frequencies of the receiving bands, a counter for counting the pulses from the astable m