Self-test heterodyne interferometric fiber optic hydrophone hardware circuit and its stability test method

Abstract

The invention provides a self-testing heterodyne interference type optical fiber hydrophone hardware circuit and a stability testing method thereof. The method comprises the steps that sinusoidal signals output by an acoustic optical modulator driving source are digitally collected and mixed with local oscillation signals generated in a high-speed digital processor, the effective ranges of frequency deviations are compared through low-pass filtering and spectral analysis, and then the stability of the heterodyne interference type optical fiber hydrophone hardware circuit is judged. The directterminal testing and verification method is high in testing precision, simple and easy, and time and energy are saved; the existing structure of an interference type optical fiber hydrophone system isnot changed, and new interference signals introduced by the acoustic optical modulator driving source and a digital circuit demodulation part are effectively avoided; in the testing method, taking-upand paying-off of an array cable part of the interference type optical fiber hydrophone system do not need to be conducted in water, the array cables are prevented from being damaged, and the testingefficiency is effectively improved. Signal demodulation is conducted by using a digital circuit, the circuit structure is simple, the timeliness is high, the transportability is high, the field programmable ability is high, and real-time programming testing is facilitated.

Description

technical field [0001] The invention relates to the field of optical fiber hydrophones, in particular to a method for self-testing the hardware circuit of a heterodyne interference type optical fiber hydrophone and its stability test. Background technique [0002] With the improvement of submarine manufacturing technology, especially the advanced submarines of the United States and Russia, the noise during underwater operation is continuously reduced, and the difficulty of detection is gradually increasing, which brings great challenges to anti-submarine warfare. Due to the shortcomings of low sensitivity and small dynamic range, traditional piezoelectric hydrophones can no longer meet the actual needs of underwater anti-submarine operations. It is favored by naval scientific research institutions and has been widely used. The outstanding advantages of the interferometric fiber optic hydrophone include: high sound pressure sensitivity, large dynamic range, free from electro...

AI Technical Summary

Problems solved by technology

In the application, construction or test sites of fiber optic hydrophones, the environment is usually relatively harsh, and the external environment (such as temperature changes, vibrations, shocks, etc.) may cause changes in the output signal frequency of the acousto-optic modulator drive source, while the output signal frequency The stability of AOM will affect the accuracy of frequency shifting of AOM

[0005] The heterodyne demodulation method is used to demodulate the signal of the interferometric fiber optic hydrophone system, and digital circuit demodulation is usually used. As mentioned above, the working stability of the digital circuit may change under the influence of the harsh external environment. For example, the output frequency of the crystal oscillator is unstable, which will further cause the working clock or timing of the digital circuit to change, resulting in timing competition, resulting in inaccurate demodulation results of the digital circuit. At the same time, the test method is cumbersome and takes a long time, especially in the field where the test time is limited. Under the condition, the test efficiency is greatly reduced

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