Modeling And Analysis Of Analog Circuits For Pulsed Laser Detection

The pulsed laser has a small divergence angle,good monochromaticity,and a large output power,and is widely used in various detection systems.Commonly used pulsed laser detection systems mostly obtain detection results based on the peak characteristics of the pulse signal,and the detection range and accuracy are limited.This article started with the modeling and analysised of the analog circuit in the pulsed laser detection system,studied the influence of the circuit on the pulse signal waveform,and calculated the final value by extracting a variety of characteristic parameters of the signal,which makes the system more adaptable.First,this article analyzed the overall structure and working principle of the pulsed laser detection system.A pulsed laser transmitter module is designed,and then two sets of self-gain amplifier circuit boards are designed with discrete components and integrated operational amplifiers to appropriately amplify the received electrical signals.A high-speed analog-todigital converter was used in the signal acquisition to save the complete pulsed laser signal for further feature extraction and analysis of the waveform.Then,the output waveform of the analog circuit waa modeled and analyzed.Starting from the pulsed laser waveform with nearly Gaussian distribution,the influence of the system's detection accuracy on waveform broadening and amplitude swimming,and the limitation of waveform saturation on the detection range were analyzed.Through the analysis of the circuit model,the influence of the non-linear capacitance inside the circuit on the charging and discharging was studied,so that the peak value of the waveform does not change after entering the saturation zone,but the overall waveform still changes when the input signal is enhanced.It verifies the possibility of extracting other still changing features from the saturated output signal to invert the parameters of the detected target.Innovatively,various features were extracted from the overall data features such as the pulse width value and the single-segment data features such as the formula parameters obtained from the waveform segmentation fitting,which completed the preparation for the application of the detection system.Finally,two sets of pulsed laser detection systems with different detection purposes were built to verify the wide applicability of the waveform decomposition feature extraction process.Aiming at the problem that the laser positioning system cannot be detected by the waveform amplitude value when the incident laser is too strong,a method is proposed to invert the incident light intensity with the amplitude value as the main and the segmented fitting parameter as a supplement,so that the system can be in the strong signal input.The detection capability is still maintained,and the measurement range is significantly improved.Aiming at the problem that when the laser ranging system detects different laser intensity at the same distance,the leadingedge time discrimination method cannot accurately locate the starting time of the signal,a method of fitting and recalculating the rising edge of the signal is proposed to determine the exact time of received echo signal.High-precision ranging can be obtained without the need to identify the circuit at all times,which verifies the feasibility of the method of waveform feature extraction in this paper to improve the measurement accuracy.