提高过零检测精度的方法研究

Method Studies in Improving Accuracy of Zero-crossing Detection

将运算放大器和专用快速比较器在过零检测中的应用进行了比较,对两种应用电路分别存在的问题,如相位误差、响应时间、对输入信号的要求等进行了分析,并提出了相应的解决办法。针对OCT电流测试系统,证明了信号的上升沿和稳定性对锁相精度的影响,提出采用运放构成两次过零比较,将入锁信号的上升沿时间△t从26.78μs降低到7.899μs,大大提升了入锁信号的的跟踪精度。

The applications of operational amplifier and professional comparator in zero-crossing detector are studied.Possible problems such as phase error, requirements of the input signals and response time,are analyzed,and the corresponding solutions are also put forward.The effect to phase-locking precision from signals rising edge and stability is verified for the OCT-current test system.Twice zero-crossing comparation is generated by adopting the applications of operational amplifier,which reduce the signal rising edge time from 26.78μs to 7.899μs,and greatly enhance the signal＇s tracking accuracy.