Wide-band crystal-controlled transceiver with remote digital tuning

Claim 1

A remotely controlled superheterodyne radio transceiver tunable to a selected channel of limited bandwidth from amongst a plurality of such channels within an operating band of frequencies, comprising a stable oscillator, means for generating a spectrum of harmonics of the output frequency of said stable oscillator, said spectrum extending throughout the band of frequencies to be tuned by said transceiver, each harmonic component of said spectrum being separated in frequency from its adjacent components by an amount equal to a plurality of channel bandwidths, a variable-frequency voltage-controlled oscillator, sweep means for generating a varying control voltage to vary the frequency of said voltage-controlled oscillator, means for mixing the output of said voltage-controlled oscillator with the output of said harmonic generator to produce a difference frequency signal, means for converting said difference frequency signal into a pulse whenever the frequency thereof equals a predetermined value, means for counting the number of said pulses produced by sweeping said voltage-controlled oscillator, each succeeding one of said pulses being produced as the difference between the frequency of said voltage controlled oscillator and successive harmonic components attains said predetermined value, a remote digital control switch, logic means for presetting said counting means to a number determined by said control switch, a plurality of fixed frequency oscillators having frequencies differing from one another by an amount substantially equal to the channel bandwidth of said radio, second logic means controlled by said remote control switch for selecting one of said fixed frequency oscillators according to the channel upon which said radio is to operate, phase lock frequency control means for comparing the phase of the output of said mixing means with the phase of the output of said selected oscillator and producing an output corresponding to the difference between said phases, means controlling said counting means so as to commence counting pulses when the frequency of said voltage-controlled oscillator is at a known value, means controlled by said counting means for arresting said sweep means and for switching the control voltage of said voltagecontrolled oscillator to the output of said phase lock means whenever said preset number of said counter is reached, means for modulating and radiating the output of said voltagecontrolled oscillator as the transmitter signal of said transceiver, and means for utilizing the output of said voltage-controlled oscillator as a local oscillator signal during reception by said transceiver.