A phase delay extraction and compensation method in pgc phase demodulation method
A phase delay and phase demodulation technology, which is applied in the field of phase delay extraction and compensation in the PGC phase demodulation method, can solve the problems that the phase delay is difficult to measure accurately and the nonlinear error is difficult to suppress in real time.
Active Publication Date: 2020-04-28
ZHEJIANG SCI-TECH UNIV
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[0003] In order to solve the problems existing in the background technology, the present invention discloses a phase delay extraction and compensation method in the PGC phase demodulation method, and the present invention solves the difficulty in accurately measuring the phase delay in the sinusoidal modulation interferometer and the nonlinear error caused by the phase delay Difficult to suppress problems in real time
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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 adopts the following phase processing system: the input terminals of the first multiplier 2, the second multiplier 3, the fifth multiplier 12, the sixth multiplier 14, the seventh multiplier 17 and the eighth multiplier 18 are all Connect the digital interference signal S (t), the first digital frequency synthesizer 1 is connected to the input end of the first multiplier 2 and the second multiplier 3, and the second digital frequency synthesizer 13 is connected to the fifth multiplier 12, the sixth multiplier The input terminal of the multiplier 14 and the third digital frequency synthesizer 16 are connected to the input terminals of the seventh multiplier 17 and the eighth multiplier 18 .
[0050] The output end of the first multiplier 2 is respectively connected to the input end of the f...
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The invention discloses a phase delay extraction and compensation method in a PGC phase demodulation method. After the sinusoidal phase modulation interference signal is amplified and filtered, it is converted into a digital interference signal by an analog-to-digital converter, and the digital interference signal is simultaneously subjected to quadrature down-mixing of the first-order, second-order and fourth-order harmonics to obtain 3 pairs of orthogonal harmonics Amplitude signal, use these 3 pairs of orthogonal harmonic amplitude signals to extract the phase delay, use the phase delay to calculate the corresponding phase delay correction coefficient, multiply the phase delay correction coefficient by the corresponding quadrature harmonic amplitude The absolute harmonic amplitude signal of the sum of the absolute values of the signals is obtained to obtain a new harmonic amplitude signal that is not affected by the phase delay, and then the phase to be measured is obtained through an arctangent operation. The invention solves 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, improves the phase measurement accuracy, and is widely used in the technical field of sinusoidal modulation interference.
Description
technical field [0001] The invention belongs to the technical field of laser interferometry, in particular to a phase delay extraction and compensation method in a PGC phase demodulation method. Background technique [0002] Phase-generated carrier (PGC) modulation and demodulation technology is widely used in interferometric fiber optic sensors and sinusoidal phase modulation interferometers due to its advantages of high phase detection sensitivity and large dynamic range. PGC modulation and demodulation technology 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 integral operations on the quadrature components. This method is easily affected by laser light intensity, carrier phase delay, and phase modulation depth. The PGC-Arctan method divides the quadrature component and performs an arctangent operation to directly ...
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IPC IPC(8): G01D5/26
CPCG01D5/26G01B9/0201G01B9/02083G01D5/35306G01B9/02072G01B9/02067
Inventor 陈本永谢建东严利平
Owner ZHEJIANG SCI-TECH UNIV