A method of measuring pulse duration

The pulse under investigation and a timing wave consisting of a succession of narrow triangular pulses of controllable frequency are simultaneously displayed on a double-beam sampling oscilloscope. Adjacent timing pulses are aligned to the leading and trailing edges of the pulse being measured; the duration of the pulse, being then identical with the period of the timing wave, is obtained from a digital frequency meter monitoring the timing-wave frequency. Pulse durations in the range 20 to 100 ns may be determined with an uncertainty of ± 100 ps. For pulses of durations extending to several microseconds the uncertainty is within ± 0.1%. The method has particular application in pulse-bandwidth measurements on television and other waveform transmission systems having pulse bandwidths in the range 125 kHz to 25 MHz. Using ancillary amplitude-measuring equipment, such measurements can be accomplished with uncertainties of ±1% or better.