Abstract: A high speed scanning radio has conventional RF amplifier, a mixer, a frequency synthesizer for the generation of local oscillator signals, an IF amplifier, a demodulator, and an audio output stage. The receiver includes a memory for storing a plurality of frequency codes corresponding to respective radio channels and a scan control for reading those codes, two for each channel, into the frequency synthesizer. A linear combination of each pair of distinct frequency codes is utilized to generate a local oscillator signal. Utilization of fractional N frequency synthesis is also disclosed.

Abstract: A high speed scanning radio has conventional RF amplifier, a mixer, a frequency synthesizer for the generation of local oscillator signals, an IF amplifier, a demodulator, and an audio output stage. The receiver includes a memory for storing a plurality of frequency codes corresponding to respective radio channels and a scan control for reading those codes, two for each channel, into the frequency synthesizer. A linear combination of each pair of distinct frequency codes is utilized to generate a local oscillator signal.

Abstract: A high speed scanning radio has conventional RF amplifier, a mixer, a frequency synthesizer for the generation of local oscillator signals, an IF amplifier, a demodulator, and an audio output stage. The receiver includes a memory for storing a plurality of frequency codes corresponding to respective radio channels and a scan control for reading those codes, two for each channel, into the frequency synthesizer. A linear combination of each pair of distinct frequency codes is utilized to generate a local oscillator signal.

Abstract: A high-speed, multi-band scanning radio receiver. A frequency synthesizer loaded with a digital code read from memory performs band switching and supplies tracking signals and a local oscillator signal to multi-band RF amplifier and mixer circuitry. An output of an FM detector in the receiver is connected to a squelch circuit which includes a high-pass filter network and a diode detector, with the diode detector output being connected to an internal A/D converter of a microprocessor which converts multiple samples of the incoming signal to digital values and generates a mute signal when the average value of the converted samples is below a predetermined squelch level. An output line from the FM detector to audio output circuitry in the receiver is grounded in response to the mute signal.