Circuit of automatic zero adjustment and amplitude modulation of interference system under low contrast and its application method

Abstract

The present invention relates to the field of optoelectronic signal processing technology, especially to an interference system automatic zero set and amplitude modulation circuit in a low contrast. The circuit comprises an interference signal photovoltaic conversion circuit, a direct current bias eliminating circuit, a voltage amplitude automatic regulation circuit and a processor. The interference signal photovoltaic conversion circuit is configured to receive interference fringes and output photoelectric digital signals; the direct current bias eliminating circuit is configured to receive the photoelectric digital signals and then perform direct current component zero set processing; the voltage amplitude automatic regulation circuit is connected with the direct current bias eliminatingcircuit and the processor to regulate a voltage value input in the processor to meet processing requirements; and the processor is connected with the direct current bias eliminating circuit and the voltage amplitude automatic regulation circuit. The interference system automatic zero set and amplitude modulation circuit in the low contrast and the application method thereof can automatically eliminate the background influence and can adapt different background light conditions as far as possible.

Description

technical field [0001] The invention relates to the technical field of photoelectric signal processing, and the specific field is a circuit for automatic zero adjustment and amplitude modulation of an interference system under low contrast and a method for using the same. Background technique [0002] Interferometry is one of the commonly used precision measurement methods, and the quality of interference fringes and signal processing methods are important factors affecting measurement accuracy. Devices that accept interference fringes mainly include CCD, PSD, and photodiodes. Photodiodes are commonly used interference fringe photodetectors because of their low cost and fast response speed. Using photodiodes to convert interference fringes into electrical signals, the current is relatively weak and needs to be amplified by triodes and operational amplifiers. However, if the intensities of the two beams of light that generate the interference fringes are inconsistent, the co...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a low-contrast interference system automatic zero-adjustment and amplitude modulation circuit to solve the problem in the prior art that the contrast is too low, which affects the recording and interpretation of fringes, and increases the difficulty of subsequent signal processing.

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