PSD (position sensitive detector) signal noise reduction method with high precision

Abstract

The invention discloses a PSD (position sensitive detector) signal noise reduction method with high precision. The PSD signal noise reduction method includes that (1), a microprocessor controls a laser to generate and discontinuously emit a square signal with certain frequency, a PSD measuring value is a background noise value on the condition of low electrical level, the PSD measuring value is the sum of an effective measuring value and the background noise value on the condition of high electrical level, and a laser pulse transmission cycle is formed on the condition of once high electrical level and low electrical level; (2), the square signal generated by the laser is irradiated to a light sensor of a PSD, AD sampling of two voltage signals of the PSD on the condition of high and low electrical levels is completed, sampling is performed at least for two times within the time length of once high or low electric level, and sample data are stored respectively; (3), after a laser impulse transmission cycle, a PSD noise reduction calculation timer is started by the microcomputer, and in timer interruption, for each PSD voltage signal, an mean value of the sample data stored during low electrical level of one PSD voltage signal is subtracted from a mean value of the sample data stored during high electrical level of the PSD voltage signal to complete PSD noise reduction of the PSD voltage signal.

Description

technical field [0001] The invention relates to a signal noise reduction method in photoelectric signal detection, in particular to a high-precision PSD signal noise reduction method. Background technique [0002] PSD is a position sensor for photodetection, the physical basis of its work is the lateral photoelectric effect. When the incident light irradiates the photosensitive part of PSD, a charge proportional to the light energy is generated at the incident position, and the charge is absorbed by the electrode through the resistive layer to form a photocurrent. The light point position of the incident light on the PSD photosensitive surface can be obtained by calculating the photocurrent ratio. Its structure is as figure 1 shown. When the incident light irradiates the photosensitive part of PSD, a charge proportional to the light energy is generated at the incident position, and the charge is absorbed by the electrode through the resistive layer to form a photocurrent....

AI Technical Summary

Problems solved by technology

This method requires additional hardware circuit design, which artificially increases the error of analog devices such as sample-and-hold chips and differential amplifiers in the signal, reduces the signal accuracy, increases the circuit scale, and adversely affects the high-precision and miniaturized design of the system.

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