Interference signal frequency tracking for extracting phase in frequency scanning interferometry using an extended Kalman filter

2016 ◽  
Vol 55 (11) ◽  
pp. 2985 ◽  
Author(s):  
Zhe Liu ◽  
Zhigang Liu ◽  
Zhongwen Deng ◽  
Long Tao
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Signal Frequency ◽  
Interference Signal ◽  
Frequency Tracking ◽  
Frequency Scanning ◽  
Frequency Scanning Interferometry

scholarly journals A Phase Difference Measurement Method Based on the Extended Kalman Filter for Coriolis Mass Flowmeters

2019 ◽  
Vol 19 (2) ◽  
pp. 48-52
Author(s):  
Nan Chen ◽  
Shangchun Fan ◽  
Dezhi Zheng
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Phase Difference ◽  
Measurement Method ◽  
Measurement Accuracy ◽  
Single Phase ◽  
Signal Frequency ◽  
Difference Measurement ◽  
Mallat Algorithm ◽  
Interference Signals

Abstract According to the characteristics of stable single-phase flow, a phase difference measurement method based on the extended Kalman filter is proposed in this paper for use with Coriolis mass flowmeters. Firstly, the Mallat algorithm is applied to filter out interference signals. Then, the frequency and phase difference of the two reconstructed signals are detected through the extended Kalman filter. Compared with the sliding Goertzel algorithm or discrete time Fourier transform, the proposed method does not need to predict the signal frequency and avoids quadratic error. Simulations and experiments show that the proposed method has stronger anti-interference, higher measurement accuracy and lower relative error than the existing method based on the Hilbert transformation.

scholarly journals Absolute Distance Measurement Using Frequency-Scanning Interferometry Based on Hilbert Phase Subdivision

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5132 ◽  
Author(s):  
Shuo Jiang ◽  
Bo Liu ◽  
Huachuang Wang ◽  
Bin Zhao
Keyword(s):  
Laser Frequency ◽  
Optical Path Difference ◽  
Path Difference ◽  
Distance Measurement ◽  
Beat Signal ◽  
Interference Signal ◽  
Time Points ◽  
Frequency Scanning ◽  
Frequency Scanning Interferometry ◽  
External Clock

In order to eliminate the influence of laser frequency nonlinearity, the frequency-scanning interferometry (FSI) often uses the beat signal of an auxiliary interferometer as the external clock. The time points at every amplitude peaks and bottoms of the auxiliary beat signal are selected as the sampling time points for the main interferometer signal. To satisfy the Nyquist sampling requirement, the optical path difference (OPD) of the delay fiber in auxiliary interferometer should be at least twice longer than the measurement distance. In this paper, we proposed a method to shorten the length of delay fiber. The Hilbert transform was used to extract the phase of the auxiliary interference signal and calculate the time points corresponding to subdivided phase intervals. Then, the main interference signal was resampled at these moments, and the fast Fourier transform was performed on the resampled signal. The experimental results showed that the target at the distance of about 5 m was measured when the OPD of the auxiliary interferometer was about 4.5 m. The standard deviation of the distance measurement results could reach 4.64 μm.

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