Precision phase sensitive demodulator

Claim 1

A PRECISION ELECTRONIC PHASE-SENSITIVE DEMODULATOR CIRCUIT COMPRISING FIRST AND SECOND HALF WAVE DEMODULATOR CIRCUITS, MEANS FOR APPLYING AN A.C. SIGNAL VOLTAGE TO EACH OF SAID HALF WAVE CIRCUITS, MEANS FOR APPLYING AN A.C. REFERENCE VOLTAGE TO EACH OF SAID HALF WAVE DEMODULATOR CIRCUITS HAVING THE SAME FREQUENCY AS BUT A GREATER AMPLITUDE THAN SAID A.C. SIGNAL VOLTAGE, SAID REFERENCE VOLTAGE GATING SAID FIRST HALF WAVE DEMODULATOR CIRCUIT ON THE FIRST HALF OF EACH CYCLE THEREOF AND GATING SAID SECOND HALF WAVE DEMODULATOR CIRCUIT ON THE SECOND HALF TO EACH CYCLE THEREOF, SAID FIRST HALF WAVE DEMODULATOR CIRCUIT PRODUCING A FIRST A.C OUTPUT SIGNAL HAVING THE FIRST HALF OF EACH CYCLE FOLLOWING THE SIGNAL VOLTAGE AND THE SECOND HALF OF EACH CYCLE BLOCKED OUT, SAID SECOND HALF WAVE DEMODULATOR CIRCUIT PRODUCING A SECOND A.C. OUTPUT SIGNAL HAVING THE SECOND HALF OF EACH CYCLE FOLLOWING THE SIGNAL VOLTAGE AND THE FIRST HALF OF EACH CYCLE BLOCKED OUT, THE SUM OF SAID FIRST AND SECOND OUTPUT SIGNALS BEING IN PHASE WITH AND HAVING THE SAME WAVEFORM AS SAID SIGNAL VOLTAGE, AND NEGATIVE FEEDBACK MEANS FOR FEEDING BACK THE SUM OF SAID FIRST AND SECOND OUTPUT SIGNALS TO SAID MEANS FOR APPLYING THE SIGNAL VOLTAGE TO REDUCE THE EFFECT OF NON-LINEARITIES IN SAID FIRST AND SECOND HALF WAVE DEMODULATOR CIRCUITS.