Phase generated carrier demodulation device and method based on phase program control

Abstract

The invention discloses a phase generated carrier demodulation device and a method based on phase program control. The device and the method are based on a sampling clock as a baseline and comprise the following: synchronously completing the analog-to-digital conversion of an interference signal and a one-time frequency multiplier carrier signal; aligning the phases of the two signals; performing frequency mixing and lowpass filtering of the phase aligned interference signal with the one-time frequency multiplier carrier signal and the two-time frequency multiplier carrier signal; and after that, the transmitting the interference signal to the demodulation module for demodulations so as to realize the demodulation of a detected signal. According to the device and the method, the interference signal and the one-time frequency multiplier carrier signal are acquired in real time, and the phase difference of the second path of signal is tracked; in accordance to the acquisition point position corresponding to the peak point, the phase difference between the carrier signal and the one-time frequency multiplier signal and the two-time frequency multiplier signal is adjusted, which not only solves the un-synchronization problem of the interference signal and the frequency multiplier signals when they go through different optical paths and circuits, but also eliminates the unfavorable influence of the random change in phase caused by carrier frequency drifting on the demodulation result, therefore, increasing the demodulation precision.

Description

technical field

[0001] The invention belongs to the field of phase generation carrier demodulation, in particular to a phase program control based phase generation carrier demodulation device and method. Background technique

[0002] The interferometric optical fiber sensing system measures the measured object by detecting the phase change of the optical signal propagating in the optical fiber, so the phase demodulation method is very important. At present, the commonly used methods mainly include active homodyne demodulation, synthetic heterodyne demodulation, pseudo heterodyne demodulation and phase generated carrier (PGC) demodulation.

[0003] The PGC demodulation method uses an unbalanced interferometer, and through high-frequency modulation of the frequency of the optical signal, a large-amplitude phase modulation signal of a fixed frequency far away from the frequency band of the measured signal is introduced into the interferometer, so that the measured signal become...

Images