Fiber laser sensor light-carried microwave signal digital demodulation system and demodulation method thereof

Abstract

The invention discloses a fiber laser sensor light-carried microwave signal digital demodulation system and the demodulation method thereof. The system is used to demodulate the light-carried microwave signal outputted from a fiber laser sensor and outputs a demodulation signal capable of restoring a wideband large dynamic sensing signal in real time. The system comprises a photoelectric conversion module, a radio frequency signal processing channel module, a high-speed analog-to-digital conversion module, and a real-time digital signal demodulation processing module. The radio frequency signal processing channel module performs automatic gain amplification and bandpass filtering on the heterodyne frequency modulation signals outputted by the photoelectric conversion module in sequence and converted into digitalized radio frequency signals by the high-speed analog-to-digital conversion module. The real-time digital signal demodulation processing module uses two channels of orthogonal local oscillator sequences to multiply the digitalized radio frequency signals respectively, and two orthogonal baseband signals are obtained from the downsampling after the low-pass filtering followed by the division, four-direction anti-tangent operation, and then the periodic expansion of the arctangent result so that the phase demodulation phase signal obtained from phase adjustment is subjected to digital differential processing.

Description

technical field [0001] The present invention relates to a demodulation system and its demodulation method in the technical field of optical fiber sensor signal demodulation, especially to a digital demodulation system and demodulation method of optical fiber laser sensor light-borne microwave signal, which is mainly used in extreme Detection of weak dynamic signals such as vibration acceleration and underwater sound pressure in the environment. Background technique [0002] Compared with various traditional sensing technologies, optical fiber sensing has the advantages of high sensitivity, anti-electromagnetic interference, good electrical insulation, corrosion resistance, low energy consumption, safe measurement, flexible and light optical fiber, and easy networking and multiplexing. Therefore, it is widely used in many special conditions. The optical fiber sensor modulates the light transmitted in the optical fiber by the measured object, changes the intensity (amplitude)...

AI Technical Summary

Problems solved by technology

Conventional spectrum analysis technology can only obtain the frequency offset, and it is difficult to dynamically provide information such as frequency and amplitude of the signal, so a special demodulation method is required

In addition, the traditional fiber laser sensor demodulation system mostly adopts analog mode, the system is easily affected by device aging, temperature drift, etc., the frequency response bandwidth of the RF analog circuit is limited, and the demodulation capability for large dynamic broadband light-borne microwave signals is insufficient

Images