Method and apparatus for measuring time delay in transmission paths

Claim 1

THE METHOD OF MEASURING THE DELAY OF A TRANSMISSION PATH WHICH COMPRISES GENERATING A SUCCESSION OF IDENTICAL MULTI-CYCLE ALTERNATING ENERGY PULSES OF A FIRST FREQUENCY, THE PULSES HAVING IDENTICAL PHASE VARIATIONS THE TIME INTERVALS BETWEEN SUCCESSIVE PULSES BEING EQUAL, SELECTING TWO SUCCESSIVE PULSES FROM THE SUCCESSION OF PULSES, TRANSMITTING SUBSTANTIALLY EQUAL PORTIONS OF THE TWO SELECTED PULSES THROUGH THE TRANSMISSION PATH, AND WITHOUT DELAY THROUGH A SECOND PATH, RESPECTIVELY, PERIODICALLY REPEATING THE SELECTION OF TWO SUCCESSIVE PULSES FROM THE SUCCESSION OF PULSES AND THE TRANSMISSION OF SUBSTANTIALLY EQUAL PORTIONS OF THE TWO SELECTED PULSES THROUGH THE TRANSMISSION PATH AND WITHOUT DELAY THROUGH A SECOND PATH, RESPECTIVELY, AT PERIODS SUFFICIENTLY ALONG THAT ECHO PULSES IN THE TRANSMISSION PATH SHALL HAVE REACHED SUBSTANTIALLY NEGLIGIBLE AMPLITUDES,COMBINING IN EACH INSTANCE THE PORTIONS OF THE TWO SELECTED PULSES TRANSMITTED THROUGH THE TRANSMISSION PATH AND THROUGH THE SECOND PATH, MEASURING IN EACH INSTANCE THE AMPLITUDE OF THE COMBINED PULSE PORTION, ADJUSTING THE TIME INTERVAL BETWEEN THE SUCCESSIVE GENERATED, MULTI-CYCLE, ALTERNATING ENERGY PULSES UNTIL THE AMPLITUDE OF THE COMBINED PULSE PORTIONS IS A MAXIMUM, CHANGING THE FREQUENCY OF THE GENERATED, MULTI-CYCLE, ALTERNATING ENERGY PULSES BY APPROXIMATELY TEN PERCENT TO A SECOND FREQUENCY AND AGAIN MEASURING THE AMPLITUDE OF THE COMBINED PULSE PORTIONS, ADJUSTING THE TIME INTERVAL BETWEEN THE GENERATED, MULTICYCLE, ALTERNATING ENERGY PULSES OF THE SECOND FREQUENCY UNTIL THE AMPLITUDE OF THE COMBINED PULSE PORTIONS IS A MAXIMUM, SUCCESSIVELY CHANGING THE FREQUENCY OF THE GENERATED, MULTI-CYCLE, ALTERNATING ENERGY PULSES FROM THE SECOND TO THE FIRST FREQUENCY AND VICE VERSA AND ADJUSTING THE TIME INTERVAL BETWEEN SUCCESSIVE GENERATED, MULTICYCLE, ALTERNATING ENERGY PULSES FOR A MAXIMUM OF THE COMBINED PULSE PORTIONS UNTIL A SINGLE TIME INTERVAL ADJUSTMENT BETWEEN SUCCESSIVE PULSES OF THE GENERATED, MULTICYCLE, ALTERNATING ENERGY PULSES IS OBTAINED WHICH PRODUCES MAXIMUM AMPLITUDE READINGS AT BOTH SAID FIRST AND SAID SECOND FREQUENCIES, WHEREBY THE DELAY OF THE TRANSMISSION PATH WILL EQUAL THE TIME INTERVAL BETWEEN SUCCESSIVE PULSES OF SAID SUCCESSION OF GENERATED, MULTI-CYCLE, ALTERNATING ENERGY PULSES FOR SAID SINGLE TIME INTERVAL ADJUSTMENT. 7.APPARATUS FOR MEASURING THE DELAY OF A SINGLE-ENDED DELAY LINE COMPRISING MEANS FOR GENERATING A REGULARLY RECURRING ALTERNATING ENERGY PULSE OF A FIRST FREQUENCY, MEANS FOR IMPRESSING THE RECURRING ENERGY PULSE ON THE LINE, THE RATE OF RECURRENCE OF THE PULSE BEING SUCH THAT THE TIME INTERVAL BETWEEN SUCCESSIVE IMPRESSED PULSES IS SUBSTANTIALLY AN INTEGRAL NUMBER OF TIMES THE ROUND TRIP DELAY OF THE LINE, MEANS FOR COMBINING A PLURALITY OF ECHO PULSES OF THE IMPRESSED PULSE FROM THE LINE, MEANS FOR MEASURING THE COMBINED ECHO PULSES, MEANS FOR CHANGING THE FREQUENCY OF THE IMPRESSED PULSES BY APPROXIMATELY TEN PERCENT, AND MEANS FOR VARYING THE TIME INTERVAL BETWEEN SUCCESSIVE IMPRESSED PULSES TO OBTAIN A MAXIMUM AMPLITUDE OF THE COMBINED ECHO PULSES WHICH REMAINS SUBSTANTIALLY CONSTANT WITH CHANGES OR FREQUENCY BETWEEN THE FIRST FREQUENCY AND FREQUENCIES WITHIN APPROXIMATELY TEN PERCENT OF THE FIRST FREQUENCY.