数字示波器大触发延迟时间的变频测量方法

摘要

针对数字示波器的大触发延迟时间,提出了一种变频测量方法.使用正弦激励信号周期作为测量尺度标准,将大触发延迟时间表述成整数个正弦周期与1个小数个正弦周期的合成.小数周期部分用相位差法直接测量获得,而整数的获取,通过相同的大触发延迟时间在不同激励信号频率下离散化时间点均具有整数个信号周期的特征而判定,最终以在极限延迟时间范围内不同频率下离散时间点最小周期的唯一性作为测量结果定量依据,并以此计算获得整数值.最后将两部分时间合成得大触发延迟时间测量结果.在数字示波器上所作的一组实验验证了该方法的正确性与可行性.该方法可用于数字示波器大触发延迟时间的精确测量和计量校准中.%Aiming at the large trigger delay of digital oscilloscope,a novel multi-frequency measurement method is presented.By using the period of sinusoidal as standard,the large trigger delay is divided into two parts,one part is just consist of many periods of sine wave,another part includes the partial period of sine wave.The partial period part can be measured through phase difference method.The integer periods part can be measured by using different frequency stimulation,of which the difference of the trigger delay value at different signal frequency has the same common period,and one can judge the minimum common period from three frequency sampling series.Then,the minimum common period can be used to calculate the number of periods.Finally,through composing of the two parts,the large trigger delay is gotten.The correctness and feasibility are proved by some experiments on digital oscilloscope,and the method can be used to the measurement and calibration of large trigger delay of digital oscilloscopes.