采用改进中值滤波器的多频相敏解调方法

Multi-frequency signal detection plays an important role in bio-impedance measurement, EM induction based non-destructive test, etc. The Phase-sensitive detection (PSD) is an effective tool for discriminating the amplitude and phase of each frequency component. The phase sensitive demodulator can be viewed as a matched filter to its source signal and is the optimal linear filter when only Gaussian noise is at presence. In many real applications, however, the noise has also rather distinctive impulsive characteristics. The impulsive noise puts forward a great challenge for the multi-frequency PSD. In this paper, an approach for the reduction of impulsive noise is introduced to improve the performance of multi-frequency PSD. The proposed method is able to achieve better signal-to-noise ratio (SNR) than its linear counterparts in processing digital signal that contaminated by impulsive noise.