High-precision digital phase-locked amplifier and weak signal detection method

The invention designs a high-precision digital phase-locked amplifier and a weak signal detection method, and the method comprises the following steps: inputting an original signal to be detected by a detector, and forming an input signal through preprocessing circuits such as a filter and an amplifier; a sine and cosine signal which has the same frequency with an input signal and has a fixed phase difference is calculated through a direct digital frequency synthesis technology, and is multiplied by the input signal, so that a phase-sensitive detection function is realized; respectively carrying out low-pass filtering on the two multiplied components through a designed filter; and finally, the amplitude and the phase of the original input signal are calculated through the vector operation module. According to the invention, by designing and optimizing the phase-locked amplification algorithm, the accuracy of weak signal detection is effectively improved, and related information such as amplitude and phase of