FPGA-based digital phase lock amplification processing method with precise automatic frequency tracking

Abstract

The invention discloses an FPGA-based digital phase lock amplification processing method with precise automatic frequency tracking. The method comprises a step of preprocessing a detected signal by asignal preprocessing circuit to obtain a discrete signal, a step of performing FFT algorithm processing on the discrete signal to obtain a rough value of a signal frequency, a step of taking the roughvalue as a center frequency and scanning the discrete signal by an FFT phase-locked loop until the frequency synchronization of two orthogonal local reference signals and the detected signal is completed, a step of multiplying the discrete signal by the two local reference signals to obtain a difference frequency term and a sum frequency term, a step of performing low-pass filtering on the difference frequency term and the sum frequency term to filter high-frequency components to obtain DC components, and a step of calculating the two DC components to obtain an amplitude and a phase of the detected signal. According to the method, the DSP Builder is used to design a program, the design of the digital phase lock amplifier is more flexible, the development is easy, an FPGA is used as a processed and a modular peripheral circuit, and so the FPGA can be conveniently applied as a module in a measuring instrument in a specific field.

Description

technical field [0001] The invention relates to the technical field of weak signal detection, in particular to a digital phase-locked amplification processing method based on FPGA-based precise automatic frequency tracking and a circuit thereof. Background technique [0002] Relevant scholars have conducted long-term research on weak signal detection technology submerged in noise. The lock-in amplifier is a mature solution with strong detection ability and high reliability in many weak signal detection. The development stage of lock-in amplifier is roughly divided into three stages: analog lock-in amplifier, analog and digital hybrid lock-in amplifier and digital lock-in amplifier. Due to the outstanding advantages of the digital lock-in amplifier, it has become a hot spot in the research of weak signal detection. [0003] At present, although there are many high-performance digital lock-in amplifiers on the market, due to their high price and complex functions, it is diff...

AI Technical Summary

Problems solved by technology

Due to the cumbersome programming of this method, it often cannot achieve good optimization and the performance of the digital lock-in amplifier is average.

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