特定消谐PWM在抑制相敏检波器谐波响应中的应用

Selective harmonic elimination PWM for the suppression of harmonic response of phase-sensitive detector

为了提高相敏检波器的带宽,解决相敏检波器存在谐波响应的问题,通过分析各种不同频率信号输入时相敏检波器的输出情况,发现相敏检波器产生谐波响应的根本原因在于采用对称方波作为参考信号,提出了采用特定消谐PWM作为相敏检波器的参考信号来有效地抑制相敏检波器谐波响应的新方法。实验结果表明,相敏检波器的谐波响应被抑制了47dB以上,带宽上限提高了3倍。

To broaden the band of the phase-sensitive detector and solve the problem of harmonic response of it, a new method to restrain the harmonic response effectively is presentes. Analyses of the output of phase-sensitive detector with all kinds of different frequency signals input, it is the symmetrical square wave as the reference signal that primarily causes harmonic response. The new method uses the se- lective harmonic elimination （PWM） as the reference signal and then is demonstrated effective by the circuit experiment. Finally, the results show that the harmonic response of the phase-sensitive detector is suppressed more than 47dB and the band of it is improved three times.