F.m. synchronous detector system

Claim 1

A SYNCHRONOUS DETECTOR SYSTEM FOR DEMODULATING ANGULAR-MODULATED SIGNAL COMPRISING AN AMPLIFIER FOR RECEIVING INCOMING WIDE-DEVIATION ANGULAR-MODULATED SIGNAL, A MODULATION TRANSFER MEANS HAVING FIRST, SECOND, AND THIRD INPUTS AND AN OUTPUT, A SYNCHRONOUS PHASE DETECTOR MEANS HAVING A FIRST INPUT FOR RECEIVING ANGULAR MODULATION SIGNAL, A SECOND INPUT FOR RECEIVING REFERENCE SIGNAL, AND AN OUTPUT FOR DEMODULATED SIGNAL, THE OUTPUT OF SAID MODULATION TRANSFER MEANS BEING CONNECTED TO THE FIRST INPUT OF SAID PHASE DETECTOR, AN OSCILLATOR OPERATING AT A FREQUENCY DIFFERENT FROM THE CARRIER FREQUENCY OF SAID INCOMING SIGNAL, THE OUTPUT OF SAID AMPLIFIER BEING CONNECTED TO SAID FIRST AND SECOND INPUTS OF SAID MODULATION TRANSFER MEANS, THE OUTPUT OF SAID OSCILLATOR BEING CONNECTED TO THE THIRD INPUT OF SAID MODULATION TRANSFER MEANS AND ALSO IN PROPER PHASE TO SAID SECOND INPUT OF SAID SYNCHRONOUS DETECTOR, SAID MODULATION TRANSFER MEANS OPERATING IN RESPONSE TO THE APPLICATION OF INCOMING SIGNAL AND OF SIGNAL FROM SAID OSCILLATOR TO DEVELOP IN THE OUTPUT OF SAID TRANSFER MEANS SIGNAL HAVING A CARRIER FREQUENCY EXACTLY EQUAL TO THE FREQUENCY OF THE SIGNAL FROM SAID OSCILLATOR AND HAVING SIGNIFICANT SIDE BANDS WITHIN A RANGE OF FREQUENCIES THAT IS MUCH MORE NARROW THAN THE RANGE OCCUPIED BY THE INCOMING SIGNAL, AND SAID PHASE DETECTOR PROVIDING SUBSTANTIALLY LINEAR DEMODULATION OVER SAID NARROW BAND OF FREQUENCIES FOR SUPPLYING DEMODULATED SIGNAL TO ITS OUTPUT WHILE SAID DETECTOR SYSTEM RETAINS FAVORABLE SIGNAL-TO-NOISE RATIO RESULTING FROM WIDE DEVIATION OF SAID INCOMING SIGNAL.