Add-subtract separator

Claim 1

AN ADD AND SUBTRACT SIGNAL SEPARATOR, FOR USE WITH A PAIR OF TRANSDUCER ELEMENTS TO PROVIDE OUTPUT SIGNALS, SAID SEPARATOR COMPRISING A PAIR OF GATING DEVICES OF WHICH THE OUTPUT OF ONE OF SAID DEVICES IS ADAPTED TO INDICATE A CONDITION OF ADD AND OF WHICH THE OUTPUT OF THE OTHER SAID GATING DEVICES IS ADAPTED TO INDICATE A CONDITION OF SUBTRACT, A FIRST ON-OFF TRIGGER FOR SUPPLYING FIRST CONTROL SIGNAL VOLTAGES TO SAID GATING DEVICES TO ENABLE SAID GATING DEVICES, A SECOND ON-OFF TRIGGER CIRCUIT FOR PRODUCING SECOND CONTROL SIGNAL VOLTAGES, MEANS FOR SUPPLYING SAID SECOND CONTROL SIGNAL VOLTAGES TO SAID GATING DEVICES IN AN OUT OF PHASE RELATIONSHIP TO PROVIDE TRIGGER PULSES TO THE GATING DEVICES WHILE SAID CONDITIONING PULSES ARE SUPPLIED THERETO, A FIRST ADD CIRCUIT FOR GENERATING FIRST BEAT FREQUENCY SIGNALS RESPONSIVE TO INPUT SIGNALS SUPPLIED THERETO, MEANS FOR SUPPLYING A PAIR OF INPUT SIGNALS TO THE SAID FIRST ADD CIRCUIT, SAID INPUT SIGNALS HAVING SUBSTANTIALLY THE SAME FREQUENCY BUT SUBJECT TO A PHASE SHIFTED RELATIONSHIP TO EACH OTHER, FIRST PEAK DETECTOR MEANS OPERATED RESPONSIVE TO THE FIRST BEAT FREQUENCY SIGNALS FOR PROVIDING FIRST DETECTED SIGNALS THAT ARE A FUNCTION OF THE AMPLITUDE OF THE SAID ADDED SIGNALS, MEANS FOR OPERATING THE FIRST ON-OFF TRIGGER CIRCUIT RESPONSIVE TO THE FIRST DETECTED SIGNALS, A SECOND ADD CIRCUIT FOR GENERATING SECOND BEAT FREQUENCY SIGNALS RESPONSIVE TO INPUT SIGNALS SUPPLIED THERETO, MEANS FOR PHASE SHIFTING ONE OF SAID PAIR OF INPUT SIGNALS, MEANS FOR SUPPLYING AND PHASE SHIFTED INPUT SIGNAL AND THE OTHER OF SAID PAIR OF INPUT SIGNALS TO SAID SECOND ADDED CIRCUIT TO GENERATE SECOND BEAT FREQUENCY SIGNALS THAT ARE PHASE SHIFTED FROM SAID FIRST BEAT FREQUENCY SIGNALS, A SECOND PEAK DETECTOR OPERATED RESPONSIVE TO SAID SECOND BEAT FREQUENCY SIGNALS FOR PROVIDING SECOND DETECTED SIGNALS THAT ARE A FUNCTION OF THE AMPLITUDE OF SAID SECOND BEAT FREQUENCY SIGNALS, AND MEANS FOR CONTROLLING THE SECOND ON-OFF TRIGGER CIRCUIT RESPONSIVE TO SAID SECOND DETECTED SIGNALS, WHEREBY SAID ONE OF SAID PAIR OF GATING DEVICES CONDUCTS WHEN SAID PHASE SHIFTED RELATIONSHIP OF SAID PAIR OF INPUT SIGNALS IS POSITIVE AND SAID OTHER OF SAID PAIR OF GATING DEVICES CONDUCTS WHEN SAID PHASE SHIFTED RELATIONSHIP OF SAID PAIR OF INPUT SIGNALS IS NEGATIVE.