测量微秒量级脉宽方波信号的电容分压器

Capacitive divider for measuring μs width square wave pulse

  • 摘要: 为了解决测量脉宽达到μs量级的方波信号的平顶衰落问题,设计了改进的双端匹配电容分压器。对采取双端匹配方式的电容分压器进行了频域和时域仿真。仿真结果表明,双端匹配方式的中频段幅频特性不平坦,方波响应波形也存在过冲。通过仿真计算调整了始端电阻以及对应的末端电容,实现了双端匹配方式的优化设计。实验结果表明:当低压臂电容为2 nF的情况下,使用电长度为50 ns的电缆的改进双端匹配电容分压器可以得到过冲小于2%,无平顶衰落的波形。

     

    Abstract: The output waveform of capacitive voltage divider has top tilt when measuring square-wave signal with pulse width of several microsecond. To solve this problem, an improved two-end matched capacitive divider is designed. The capacitive divider with two-end matching modes is simulated in frequency domain and time domain. The simulation results show that the linearity of the amplitude-frequency characteristic of the capacitive divider is not good in the middle frequency band. And the output waveform of the divider has overshoot when it responds to square wave signals. The calculation method of the beginning resistance and the corresponding terminal series capacitance has been improved, and the two-end matched capacitive divider has been improved. The experimental results show that when the low-voltage arm capacitance of divider is 2 nF and the electric length of the signal cable is 50 ns, the output waveform of the improved two-end matched capacitive divider has no top tilt , and the overshoot is less than 2%.

     

/

返回文章
返回