PGC phase demodulation method for compensating carrier phase delay nonlinear error

A nonlinear error and carrier phase technology, applied in the direction of converting sensor output, measuring devices, instruments, etc., can solve the problems of phase delay difficult to accurately measure nonlinear error, difficult to compensate in real time, etc.

Active Publication Date: 2020-08-28
ZHEJIANG SCI-TECH UNIV
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Problems solved by technology

[0003] In order to overcome the deficiencies in the prior art, the present invention discloses a PGC phase demodulation method that compensates the nonlinear error of the carrier phase delay, solves the influence of the phase delay in the PGC demodulation, and solves the problems in the PGC phase demodu

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  • PGC phase demodulation method for compensating carrier phase delay nonlinear error
  • PGC phase demodulation method for compensating carrier phase delay nonlinear error
  • PGC phase demodulation method for compensating carrier phase delay nonlinear error

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[0048] The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

[0049] Such as figure 1 As shown, the specific implementation of the method adopts the following PGC phase demodulation system, and the input terminals of the first multiplier 2, the second multiplier 3, the third multiplier 19 and the fourth multiplier 20 are all connected to the digital interference signal S (t); The output end of the first digital frequency synthesizer 1 is connected to the input end of the first multiplier 2 and the second multiplier 3 respectively, and the output end of the first multiplier 2 is connected to the input end of the first low-pass filter 4, the second The output end of the second multiplier 3 is connected to the input end of the second low-pass filter 5; the output end of the first low-pass filter 4 is respectively connected to the input end of the second square operator 9, the first sign extractor 26 Input end, the...

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Abstract

The invention discloses a PGC phase demodulation method for compensating carrier phase delay nonlinear errors. A high-frequency sine and low-frequency sine scanning composite modulation method is adopted. The first-order and second-order orthogonal down-mixing is carried out on the sampled composite sinusoidal modulation digital interference signal; two pairs of orthogonal amplitude signals are obtained; a first-order orthogonal amplitude signal and a first-order orthogonal differential signal are used to accurately extract phase delay and compensate the phase delay; the first-order orthogonalamplitude signal and the second-order orthogonal amplitude signal are optimized according to the phase delay to obtain two paths of new amplitude signals which are not influenced by the phase delay,a composite phase is obtained through arc tangent and phase unwrapping operation, and finally a to-be-measured phase is obtained through moving average calculation. According to the method, the problems that the phase delay is difficult to accurately measure and the nonlinear error caused by the phase delay is difficult to compensate in real time in the PGC phase demodulation technology are solved, the phase measurement precision is improved, and the method can be widely applied to the technical field of sinusoidal phase modulation interference.

Description

technical field [0001] The invention belongs to the technical field of laser interferometry, in particular to a PGC phase demodulation method for compensating carrier phase delay nonlinear error. Background technique [0002] Phase-generated carrier (PGC) demodulation technology is widely used in interferometric fiber optic sensors and sinusoidal phase modulation interferometers due to its advantages of low-frequency interference resistance, high sensitivity, and large dynamic range. PGC demodulation technology mainly includes differential cross multiplication algorithm (PGC-DCM) and arctangent algorithm (PGC-Arctan). The PGC-DCM method obtains the phase to be measured by performing differential cross multiplication and integration operations on the quadrature signal, which is easily affected by fluctuations in laser light intensity, carrier phase delay, and phase modulation depth. The PGC-Arctan method divides the quadrature component and performs an arctangent operation t...

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Application Information

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IPC IPC(8): G01J9/02G01D5/353
CPCG01D5/35306G01J9/02G01J2009/0249
Inventor 严利平陈本永张倚得谢建东
Owner ZHEJIANG SCI-TECH UNIV
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