Wave analysis

Claim 1

A SYSTEM FOR MEASURING A SELECTED FREQUENCY COMPONENT OF A PRESELECTED SEGMENT OF A COMPLEX WAVE RECORDED IN PHONOGRAPHICALLY REPRODUCIBLE FORM TOGETHER WITH A FIRST MARKER AT THE BEGINNING AND A SECOND MARKER AT THE END OF SAID PRESELECTED SEGMENT OF SAID RECORDED WAVE WHICH COMPRISES MEANS FOR PRODUCING A FIRST SIGNAL COMPRISING A VOLTAGE WHICH VARIES IN MAGNITUDE IN ACCORDANCE WITH SAID COMPLEX WAVE DURING A SCALED TIME INTERVAL RELATED TO THE ORIGINAL TIME-DURATION OF SAID SELECTED SEGMENT OF SAID COMPLEX WAVE BY A SCALING FACTOR, AN OUTPUT CIRCUIT INCLUDING MEANS FOR MULTIPLYING SAID FIRST SIGNAL BY A SINE FUNCTION WHOSE FREQUENCY IS RELATED TO SAID SELECTED FREQUENCY COMPONENT BY SAID SCALING FACTOR, A SHORTING CIRCUIT CONNECTED ACROSS SAID OUTPUT CIRCUIT, MEANS FOR PRODUCING A SECOND SIGNAL FROM SAID FIRST MARKER AT THE BEGINNING OF SAID PRESELECTED SEGMENT, CONTROL MEANS RESPONSIVE TO SAID SECOND SIGNAL FOR OPENING SAID SHORTING CIRCUIT, A CIRCUIT CONNECTED TO SAID OUTPUT CIRCUIT FOR INTEGRATING SAID MULTIPLIED VOLTAGE WHEN SAID SHORTING CIRCUIT IS OPEN, AND MEANS FOR PRODUCING A THIRD SIGNAL FROM SAID SECOND MARKER FOR CLOSING SAID SHORTING CIRCUIT IN TIME-COINCIDENCE WITH THE END OF SAID PRESELECTED SEGMENT.