A four-quadrant detection module and its application method

Abstract

The invention discloses a four-quadrant detection module and an application method thereof. The four-quadrant detection module includes a four-quadrant detector, an adjustable RLC network, a DC signal amplification module, an AC signal amplification module and a signal conditioning circuit. The four-quadrant detector converts the optical signal into a current signal; the adjustable RLC network separates the DC component and the AC component of the current signal, and the adjustable resistor network is used to fine-tune the junction capacitance of the detector, and the inductive reactance is used to suppress the signal frequency. Voltage noise gain; the AC signal amplifying module converts the current AC component into a voltage signal, and the fine-tuning feedback resistor network in it realizes the fine-tuning of the signal gain. The invention improves the response consistency between the quadrants of the four-quadrant detection module through the adjustable resistance network, thereby optimizing the common mode rejection ratio; using the response characteristics of the inductance, the noise performance near the signal frequency is greatly optimized, and has high common mode rejection ratio and high gain. It has the advantages of low noise and is suitable for weak signal detection.

Description

technical field [0001] The invention relates to the field of photoelectric detection, in particular to a four-quadrant detection module and an application method thereof. Background technique [0002] A four-quadrant detector consists of four identical photodetectors arranged in four quadrants. Usually, the laser beam irradiating the photosensitive surface of the four-quadrant detector uses a circular spot with uniform energy distribution. When the beam irradiates the surface of the four-quadrant detector, if the center of the beam is located at the center of the four-quadrant detector, the optical power received by each quadrant is the same. , output the same photocurrent; if the center of the beam deviates from the center of the four-quadrant detector, the received light energy will also change due to the different spot areas in the four quadrants, resulting in photocurrents of different intensities, so the photocurrent changes can be Calculate the displacement change of ...

AI Technical Summary

Problems solved by technology

Limited by the large DC component of the photocurrent and the maximum reverse bias voltage of the four-quadrant detector, the DC equivalent impedance of the DC blocking resistor cannot be too large. However, from the analysis of the noise model, the smaller the DC blocking resistor, the greater the input voltage noise gain of the four-quadrant detection module. The larger the value, the DC blocking resistance is too small, which will degrade the noise performance of the detection module

The existing four-quadrant detection module generally uses a fixed RC network to block DC, and its DC blocking resistance does not change with frequency, thus greatly restricting the noise performance of the detection module

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