CALCULATION METHOD FOR SIGNAL WAVEFORM TRANSITION DURATION

PURPOSE:To calculate fall and rise durations of digitally measured very noise transient waveform accurately by storing the transient waveform of signals by digital measurement and obtaining a histogram at levels on the screen of the measured waveform. CONSTITUTION:First a transient waveform of signals is measured digitally and stored. Next, by using a digital computer, a histogram is obtained at levels on the screen of its measured waveform. Then the highest two values of the histogram are specified as H and L levels. When the potentials of the H and L levels are specified, the potentials of 90% amplitude and 10% amplitude are obtained by calculation. Then the envelope of the transient waveform part is obtained. Because the value obtained is measured digitally, the envelope has as allowance on upper and lower sides. Therefore the average value of the upper and lower envelopes is approximated mostly to the true transient waveform of a waveform. Thus points of time at which the line of its average value is intersected with the levels of 90% and 10% amplitudes are obtained, and their time difference is specified as fall time.