Frequency modulation meter

Claim 1

A FREQUENCY MODULATION METER CIRCUIT FOR PROVIDING A VOLTAGE ANALOG OF THE INSTANTANEOUS FREQUENCY OF A FREQUENCY MODULATED INPUT WAVE, COMPRISING A WAVEFROM CONVERTER PROVIDING A RECTANGULAR WAVE OUTPUT OF CONSTANT AMPLITUDE AND OF PERIOD EQUAL TO THAT OF SAID INPUT WAVE, A FREQUENCY-TO-AMPLITUDE TRANSLATOR COMPRISING A GATE CONTROL CIRCUIT RESPONSIVE TO SAID RECTANGULAR WAVE AND A RAMP VOLTAGE GENERATOR INCLUDING A CUMULATING CAPACITOR AND MEANS RESPONSIVE TO HALF PERIOD GATING SIGNALS FROM SAID GATE CONTROL CIRCUIT CAUSING SAID CUMULATING CAPACITOR TO CHARGE LINEARLY THEREBY PRODUCING RAMP VOLTAGES HAVING PEAK AMPLITUDES PROPORTIONAL TO THE PERIODS OF SAID REACTANGULAR WAVES, AND AN AMPLITUDE DEMODULATOR COMPRISING A FOUR DIODE SWITCH HAVING TWO PARALLEL BRANCHES EACH INCLUDING A PAIR OF SERIALLY CONNECTED DIODES, AND CIRCUIT MEANS CONNECTING SAID CUMULATING CAPACITOR TO SAID FOUR DIODE SWITCH, SAID CIRCUIT MEANS INCLUDING CONNECTIONS APPLYING SAID RAMP VOLTAGES ACROSS SAID TWO BRANCHES IN SERIES WITH A CHARGING NETWORK LIMITING CONDUCTION TO A RESTRICTED ANGLE NEAR THE PEAKS OF SAID RAMP VOLTAGES, AND OTHER CONNECTIONS APPLYING SAID RAMP VOLTAGES ACROSS THE JUNCTION POINTS OF THE DIODES IN SAID TWO BRANCHES IN SERIES WITH A MEMORY CAPACITOR, WHEREBY TO DEVELOP ACROSS SAID MEMORY CAPACITOR A CHARGE WHICH FOLLOWS THE SUCCESSIVE PEAKS OF SAID RAMP VOLTAGES AND CORRESPONDS TO SAID INSTANTANEOUS FREQUENCY.