Frequency synthesizing system for AM·SSB transceiver

Claim 1

A frequency synthesizing system for use in an AM·SSB transceiver of double conversion type comprising a PLL synthesizer, said system comprising: a single crystal oscillator generating a fundamental frequency X o of said PLL synthesizer given by the equation X.sub.o =2×M×f.sub.2 IF where M is a positive integer, and f 2 IF is a second intermediate frequency; means for dividing the fundamental frequency X o by the factor of M to provide a frequency f 1 which is two times the second intermediate frequency f 2 IF and given by the equation f.sub.1 =(X.sub.o /M)=2×f.sub.2 IF; means for dividing the frequency f 1 by the factor of 2 to provide said second intermediate frequency f 2 IF given by the equation f.sub.2 IF=(f.sub.1 /2); means for mixing said fundamental frequency X o and said frequency f 1 to provide a frequency f 2 which represents the sum of them or the difference therebetween and is given by the equation f.sub.2 =X.sub.o +2×f.sub.2 IF; means for providing a first intermediate frequency f 1 IF which represents the sum of said fundamental frequency X o and said second intermediate frequency f 2 IF or the difference therebetween and is given by the equation f.sub.1 IF=X.sub.o ±f.sub.2 IF; means for dividing said second intermediate frequency f 2 IF or said frequency f 1 =2×f 2 IF to provide one of the two inputs to a phase comparator in said PLL synthesizer for energizing said PLL synthesizer; and voltage controlled oscillator means for providing an output frequency f vco of said PLL synthesizer which frequency represents the sum of a transmitting and receiving frequency f T ,R and said first intermediate frequency f 1 IF or the difference therebetween and is given by the equation f.sub.vco =f.sub.T,R ±f.sub.1 IF whereby all the frequencies required for the operation of the AM·SSB transceiver can be provided by the oscillation of the single crystal oscillator generating the fundamental frequency of said PLL synthesizer.