PGC multi-sensor measurement system using pseudo-random code division multiplexing

Abstract

The invention discloses a PGC multi-sensor measurement system using pseudo-random code division multiplexing, and belongs to the technical field of the photoelectric detection. The system comprises anarrow-line wide-light source, a code division modulation-demodulation device, a multi-probe array, a photoelectric detector and a rear demodulation device. The laser performs modulation through an external sine signal, the modulated signal is added in the pseudo random noise code by the EOM to perform multiplexing; a corresponding signal of a sensing array of rear sensors is in interference afterbeing de-multiplexed, and then the subsequent PGC demodulation is performed. The system is sued for performing PGC multiplexing and modulation and demodulation under the condition of being limited bythe space and the cable amount; the optical interference signals of multiple back-end sensors can be demodulated in time-division, and the noise and narrow-band noise in a communication link can be effectively resisted due to the importing of the random code; the differential detection is performed at the demodulation end by utilizing the photoelectric detector characteristic, thereby eliminatingthe DC noise; the system can be used for the manufacturing of the PGC vibration sensor or used as the optical hydrophone single-fiber multi-sensor multiplexing scheme based on the PGC technology.

Description

technical field [0001] The invention belongs to the technical field of photoelectric detection, and in particular relates to a PGC multi-sensor measurement system using code division multiplexing of pseudo-random codes. Background technique [0002] The interferometric optical fiber sensor uses the phase change in the optical path to indirectly measure the physical quantity to be measured, including vibration, stress, displacement, speed, etc. This method has the characteristics of high sensitivity, good linearity, small size and large dynamic range. Typical fiber optic sensor applications include fiber optic hydrophones, fiber optic seismometers, fiber optic strain gauges, etc. Fiber-optic seismometers can monitor large-amplitude signals such as earthquakes and nuclear explosions. Optical fiber hydrophones are used to monitor underwater invisible targets and blind areas that cannot be detected by radar. [0003] The phase change in the optical path needs to be solved by ...

AI Technical Summary

Problems solved by technology

[0007] Space-division multiplexing technology has the advantages of simple structure, easy implementation and no crosstalk, but its transmission efficiency is low, wasting fiber bandwidth resources, and it is not suitable for large-scale multiplexing array applications, and the system cost in remote transmission applications very big

Due to the use of multiple light sources with different wavelengths, the wavelength division multiplexing technology is expensive and limited by the adjustable accuracy of the light source

Time-division multiplexing technology cannot continuously observe a single sensor because of the query operation

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