A pgc multi-sensor measurement system using code division multiplexing of pseudo-random codes

Abstract

The invention discloses a PGC multi-sensor measurement system using code division multiplexing of pseudo-random codes, which belongs to the technical field of photoelectric detection. The invention includes a narrow line width light source, a code division modulation and demodulation device, a multi-probe array, a photoelectric detector and a post demodulation device. The laser is modulated by an external sinusoidal signal, and the modulated signal is multiplexed by adding a pseudo-random noise code to the EOM. The corresponding signals of the rear sensor sensing array are demultiplexed and then interfered for subsequent PGC demodulation. The present invention is suitable for multiplexing and modulation and demodulation of PGC under the condition of limited space and limited number of cables; it can demodulate the optical interference signals of multiple sensors at the back end in time division, and at the same time, the introduction of random codes can effectively resist Noise and narrow-band noise in the communication link; the demodulation end uses the properties of photodetectors to perform differential detection to eliminate DC noise; it can be used in the production of PGC vibration sensors or as a single-fiber multi-sensor multiplexing solution for optical hydrophones based on 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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