激光窄脉冲信号探测电路的设计与接收

在激光反射层析成像雷达系统中,激光脉宽越窄,系统的成像分辨率越高。而高带宽、无失真的探测接收电路设计起来较为困难。详细分析了雪崩光电二极管(Avalanche Photodiode,APD)模型及其主要性能参数,并选择了合适的探测器。然后对前置放大电路、主放大电路和可控增益放大电路进行了较为详细的分析,并设计了合适的电路结构。GHz级微弱光电信号在被接收时很容易受到外部噪声的干扰,这会导致接收波形产生畸变。采用电磁辐射屏蔽方法消除了干扰,最终无失真地探测和接收到了1 ns窄脉冲激光信号,满足了激光反射层析成像雷达系统的0.15 m成像精度要求。

Design of Narrow Pulse Laser Detection Circuit and Its Receiving

In a laser reflective tomography imaging radar system, the narrower the laser pulse is, the higher imaging resolution the system has. But it is difficult to design a large bandwidth and undistorted photoelectric detection circuit. An avalanche photodiode (APD) model and its main parameters are analyzed in detail. An appropriate detector is selected. After the preamplifier, main amplifier and automatic gain amplifying circuits are analyzed, a proper circuit structure is designed. When the GHz-level weak photoelectric signals are being received, they are easy to interfer with the external noise introduced. This may cause the received waveform to be distorted. By using an electromagnetic radiation shielding method to remove the interference, a 1 ns narrow pulse laser signal without distortion is received. The imaging resolution requirement of 0.15 m for the laser reflective tomography imaging radar system is met.