High sensitivity receiving circuit applied to pulse laser radar system

Abstract

The invention provides a high sensitivity receiving circuit applied to a pulse laser radar system. The circuit herein includes a photodiode, a data selector and also a first channel and a second channel which are disposed between the photodiode and the data selector. The photodiode serves as signal sampling input of the receiving circuit. The data selector serves as signal output of the receivingcircuit. The first channel includes a channel selection switch S1, a trans-impedance amplifier, a first-order RC differentiating circuit, a voltage amplifier 1, a zero-crossing comparator 1 and a threshold comparator 1. The second channel includes a channel selection switch S2, a charge sense amplifier, a main second-order RC differentiating circuit, a voltage amplifier 2, a zero-crossing comparator 2, a threshold comparator 1 and a threshold comparator 2. According to the invention, the trans-impedance amplifier and the charge sense amplifier serve as pre-positioned amplifiers, so that low noise and ultra-wide dynamic range can be realized, the time discrimination circuit can be realized with the first-order and second-order differentiating circuits, the voltage amplifiers and zero-crossing comparators. The receiving circuit herein also reduces cost and ensures high precision.

Description

technical field [0001] The invention relates to a high-sensitivity receiving circuit applied to a pulse laser radar system. Background technique [0002] A pulsed laser radar system usually includes four parts: a controller, a transmitting drive circuit, a receiving circuit, and a high-precision time measurement module (refer to the attached figure 1 ), which uses the TOF (Time of Flight, time of flight) principle for distance measurement. Its working principle is: when the distance measurement starts, the controller sends a "START" signal to the emission drive circuit to drive the laser diode to emit narrow pulse laser. At the same time, the "START" signal also triggers the high-precision time measurement module to start timing; when the pulse After the laser is diffusely reflected by the target, the echo signal passes through the photodiode to generate a current pulse signal, and the signal is processed by the receiving circuit to generate a STOP signal. After receiving t...

AI Technical Summary

Problems solved by technology

[0004] 1). The frontier time identification method cannot eliminate the walking error of the pulse echo signal, so the measurement error is often large;

[0005] 2) The dynamic range of the variable gain amplifier is very limited and cannot achieve an ultra-wide dynamic range;

[0006] 3) Although the constant ratio identification method can eliminate the walking error, it needs to cooperate with an accurate delayer. A simpler delayer will lead to an increase in error, and an accurate delayer will lead to an increase in cost;

[0007] 4) The receiving circuit designed with transimpedance amplification often has large noise, so it is difficult to obtain high sensitivity

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