PGC-DCDM demodulation method insensitive to phase delay and modulation depth

A technology of modulation depth and phase delay, applied in the direction of converting sensor output, using optical devices to transmit sensing components, measuring devices, etc., can solve problems such as influence, and achieve the effects of large dynamic range, simple implementation, and good real-time performance.

Active Publication Date: 2019-11-05
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-DCDM demodulation method that is insensitive to phase delay and modulation depth, by performing differential cross division on the quadrature signal obtained by low-pass filtering in PGC demodulation Re-multiplication (DCDM) operation, while solving the influence of phase delay and modulation depth on phase demodulation in PGC demodulation

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[0033] The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

[0034] Such as figure 1As shown, the specific implementation of the present invention includes a digital frequency synthesizer 1, a frequency multiplier 2, a first multiplier 3, a second multiplier 4, a first low-pass filter 5, a second low-pass filter 6, a first differential Calculator 7, second differential calculator 8, first divider 9, second divider 10, third multiplier 11, absolute value calculator 12, square root calculator 13, sign calculator 14, fourth multiplier 15, integral operator 16, high-pass filter 17; Digital frequency synthesizer 1 output end is connected to the input end of frequency multiplier 2 and the first multiplier 3 respectively, and frequency multiplier 2 output end is connected to the second multiplier 4 Input end, the output end of the first multiplier 3 and the second multiplier 4 are respectively connected to the first ...

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Abstract

The invention discloses a PGC-DCDM demodulation method insensitive to phase delay and modulation depth. A sinusoidal phase modulation digital interference signal is separately multiplied by a first-order reference signal and a second-order reference signal and subjected to low-pass filtering to obtain a pair of orthogonal signals related to a to-be-detected phase; the orthogonal signals are subjected to operations of differential cross division and multiplication to obtain an absolute value for extraction of a square root in order to obtain an absolute value of a derivative of the to-be-detected phase; a sign of the derivative of the to-be-detected phase is obtained according to a result obtained after differential cross multiplication and division; the absolute value is combined with thesign to obtain the derivative of the to-be-detected phase; the to-be-detected phase is obtained through an integral operation and a high-pass filtering operation. The method overcomes the influence oferror factors introduced by phase delay and modulation depth in PGC demodulation on a demodulation result, phase demodulation precision is effectively improved, and the method can be widely applied to the fields of interference type optical fiber sensors, sinusoidal phase modulation interferometers and the like.

Description

technical field [0001] The invention relates to the technical field of Phase Generation Carrier (PGC) demodulation, in particular to a PGC-DCDM demodulation method insensitive to phase delay and modulation depth. Background technique [0002] The Phase Generation Carrier (PGC) demodulation technology transfers the phase information to be measured to the sideband of the high-frequency carrier and its high-order harmonics by introducing a high-frequency carrier signal, which has anti-low-frequency interference, high sensitivity, large dynamic range, and anti-phase Fading and other advantages are widely used in the phase demodulation of interferometric fiber optic sensors, self-mixing interferometers and sinusoidal phase modulation interferometers. The PGC demodulation technology mainly includes differential cross multiplication algorithm (PGC-DCM) and arctangent algorithm (PGC-Arctan). Both algorithms multiply the interference signal with the reference carrier signal and its d...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01D5/26
CPCG01D5/266G01D5/268
Inventor 张世华陈本永严利平陈元棚
Owner ZHEJIANG SCI-TECH UNIV
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