| 摘要 |
The present invention provides a method for measuring the waveform capture rate of parallel digital storage oscilloscope. On the basis of double pulse measurement, and in consideration of the asymmetry of acquisition and the refreshing time of parallel DSO, the present invention provides a step amplitude-frequency combined pulse measurement to measure the time for waveform acquisition and mapping Tmap, the number of captured waveforms before LCD refreshing Wacq and the dead time caused by LCD refreshing TDDT, and then calculates the actual measured average WCR of parallel DSO, according to the measured data, so that the WCR of parallel can be measured. |
| 主权项 |
1. A method for measuring the waveform capture rate of parallel digital storage oscilloscope, comprising the following steps:
(1) setting the parallel DSO with the time base which is corresponding to maximal WCR and provided by manufacture, and obtaining the shortest capture time Tdp of parallel DSO by double pulses measurement, wherein the maximal WRC is 1/Tdp. 2) locating the position of dead time caused by LCD refreshing and obtaining the number of waveforms before the refreshing of LCD through step amplitude-frequency combined pulse;
2.1) structuring a step amplitude-frequency combined pulse, wherein:each pulse intervals of the step amplitude-frequency combined pulse are identical, i.e., the time intervals between the rising edges of each two consecutive pulses of the step amplitude-frequency combined pulse are identical, and the shortest capture time Tdp is taken as the pulse interval;the step amplitude-frequency combined pulse have X pluralities of pulses, each plurality of pulses have Y pulses which amplitudes increase progressively, and the pulses in same order of each plurality of pulses have the same amplitude; the pulses in same plurality of pulses have the same pulse width, and the pulse widths of X pluralities of pulses increase progressively;the pulse amplitudes, pulse widths and amplitude increments in a plurality of pulses, and pulse width increments of two consecutive pluralities of pulses satisfy the observer to view the waveform on LCD;2.2) setting the parallel DSO with the time base which is corresponding to maximal WCR and provided by manufacturer, setting the parallel DSO with the input sensitivity that can make the maximal amplitude of the step amplitude-frequency combined pulse be displayed;generating the first step amplitude-frequency combined pulse signal using a programmable arbitrary waveform generator, and inputting it into the parallel DSO as measuring signal, wherein the first step amplitude-frequency combined pulse signal comprises only one step amplitude-frequency combined pulse;generating the second step amplitude-frequency combined pulse signal using a programmable arbitrary waveform generator, and inputting it into the parallel DSO as measuring signal, when the whole step amplitude-frequency combined pulse is displayed; and wherein the second step amplitude-frequency combined pulse signal comprises a start pulse and a step amplitude-frequency combined pulse, the time interval between the start pulse and the step amplitude-frequency combined pulse is Tseg=Tdp×X×Y;generating the third step amplitude-frequency combined pulse signal using a programmable arbitrary waveform generator, and inputting it into the parallel DSO as measuring signal, when the whole step amplitude-frequency combined pulse is displayed; and wherein the third step amplitude-frequency combined pulse signal comprises a start pulse and a step amplitude-frequency combined pulse, the time interval between the start pulse and the step amplitude-frequency combined pulse is Tseg=2×Tdp×X×Y;generating and judging the like, until only part of the step amplitude-frequency combined pulse is displayed; wherein the amplitude-frequency combined pulse signal inputted is P, and the time before position of dead time caused by LCD refreshing, i.e. the time for waveform acquisition and mapping is:
Tmap=(P−1)·Tseg+Tseg—P where Tseg—P is the time corresponding to the displayed part of the step amplitude-frequency combined pulse, thus the position of dead time caused by LCD refreshing is located.obtaining the number of captured pulses Wseg—k by observing the LCD of parallel DSO, when the step amplitude-frequency combined pulse signal k has been measured; wherein the number of waveforms that parallel DSO can capture before LCD refreshing is:Wacq=∑k=1PWseg_k (3) measuring the dead time caused by LCD refreshing, and calculating the average WCR of parallel DSO; structuring a step amplitude-frequency combined pulse for measuring the dead time caused by LCD refreshing, wherein the structuring is identical with that of step 2.1 except pulse interval; generating the a step amplitude-frequency combined pulse signal using a programmable arbitrary waveform generator, and inputting it into the parallel DSO as measuring signal, wherein the step amplitude-frequency combined pulse signal comprises only one step amplitude-frequency combined pulse, the pulse interval T1 of the step amplitude-frequency combined pulse increases from Tmap/(X×Y) progressively, until the number of pulses displayed on the LCD of parallel DSO stop decreasing and increases; obtaining the number of pulses WDL in the dead time caused by LCD refreshing through observing the LCD of parallel DSO:
TDDT=WDL×T1 calculating the actual measured average WCR of parallel DSO, according to the measured data:WCRave=1(s)TDDT+Tmap×Wacq |
