Vibration analyzing apparatus

Claim 1

IN APPARATUS OF THE TYPE ADAPTED TO PRODUCE A PULSED OUTPUT SIGNAL IN WHICH EACH PULSE IS FIXED IN PHASE WITH RESPECT TO AN ALTERNATING CURRENT INPUT SIGNAL APPLIED RESPECT AND WHEREIN BANDPASS FILTER MEANS ARE INCLUDED IN THE APPARATUS FOR ELIMINATING SIGNALS HAVING A FREQUENCY SUBSTANTIALLY DIFFERENT THAN THAT TO WHICH THE FILTER IS TUNED, THE COMBINATION OF MEANS FOR COMPENSATING FOR A SHIFT IN PHASE OF THE ALTERNATING CURRENT SIGNAL IN PASSING THROUGH SAID BANDPASS FILTER MEANS DUE TO SLIGHT VARIATIONS IN THE FREQUENCY OF SAID ALTERNATING CURRENT INPUT SIGNAL, COMPRISING A PAIR OF SIGNAL CHANNELS COUPLED TO THE OUTPUT OF SAID BANDPASS FILTER MEANS, MEANS IN ONE OF SAID CHANNELS FOR PRODUCING A FIRST SYMMETRICAL SQUAREWAVE SIGNAL HAVING A FREQUENCY EQUAL TO SAID ALTERNATING CURRENT SIGNAL AND WHICH IS SHIFTED IN PHASE BY 90* WITH RESPECT TO THE SIGNAL AT THE OUTPUT OF SAID BANDPASS FILTER MEANS, MEANS IN SAID SECOND CHANNEL FOR PRODUCING SECOND AND THIRD SYMMETRICAL SQUARE-WAVE SIGNALS EACH HAVING A FREQUENCY EQUAL TO SAID ALTERNATING CURRENT INPUT SIGNAL, THE SECOND SQUARE-WAVE SIGNAL BEING SHIFTED IN PHASE WITH RESPECT TO SAID ALTERNATING CURRENT INPUT SIGNAL BY AN AMOUNT EQUAL TO TWICE THE PHASE SHIFT EFFECTED BY SAID BANDPASS FILTER MEANS, THE THIRD SQUARE-WAVE SIGNAL BEING SHIFTED IN PHASE WITH RESPECT TO THE SECOND SQUAREWAVE SIGNAL BY 180*, MEANS COUPLED TO SAID SECOND CHANNEL FOR PRODUCING A SAWTOOTH WAVE FORM, AND MEANS RESPONSIVE TO SAID FIRST, SECOND AND THIRD SQUARE-WAVE SIGNALS AS WELL AS SAID SAWTOOTH WAVE FORM FOR PRODUCING A PULSED OUTPUT SIGNAL HAVING A FREQUENCY CURRENT SIGNAL TO THE FREQUENCY OF SAID INPUT ALTERNATING CURRENT SIGNAL AND IN WHICH EACH PULSE IS FIXED IN PHASE WITH RESPECT TO SAID ALTERNATING CURRENT INPUT SIGNAL.