Detection of weak Modulation signal by Digital Phase-locked Amplifier

Abstract In the signal detection of two-dimensional material light modulation spectrum, the modulation signal is very weak and often submerged in the noise, so it is difficult to detect the modulation signal in the research. In order to detect weak modulation signals, according to the principle of digital phase lock amplification, this paper realizes the orthogonal digital phase lock method in MATLAB, and studies the extraction of modulation signals in the optical modulation spectrum. The results show that when the average noise is 20 μV, the digital phase-locked amplifier can effectively extract the modulation signal of 1 μV. When the amplitude, phase and type of modulation signal change, the extraction of modulation signal will not be affected.