基于FPGA的位置幅度调制脉冲序列生成

FPGA Based Position-Amplitude Modulated Pulse Sequence Generation

将位置幅度随机调制的脉冲序列用作汽车激光雷达发射信号的波形,可以实现目标距离测量的同时利用多普勒测量目标的速度。为产生位置幅度调制的光脉冲序列,需要在光电调制器的RF端口上施加相应的电脉冲序列。本文针对这一需求,利用信号处理状态机在FPGA上设计脉冲位置随机分配、统计脉冲间隔,并根据脉冲间隔使用信号放大模块,完成对脉冲的放大,实现位置幅度调制的电脉冲序列。最后,对所得的电脉冲序列用数值仿真的方法实施多普勒调制,验证多普勒信号的频率计算方法。结果表明,本文所得的电脉冲序列可以用于调制光信号,实现激光雷达距离和速度同时测量。

Vehicle laser radar can realize target velocity measurement by Doppler while keeping range measurement function when position-amplitude randomly modulated pulse sequences are used as its transmitting waveform. In order to generate position-amplitude modulated optical pulse sequence,corresponding electric pulse sequence is required to apply on the RF port of opto-electric modulator. For dealing with this demand,a state machine for signal processing is utilized on an FPGA to randomly assign pulse positions and count pulse intervals. Then a module for signal amplifying is used to amplify pulses according to their intervals. In this way,the position-amplitude modulated electric pulse sequence is produced. Finally,the obtained electric pulse sequence is modulated numerically by Doppler for verifying Doppler frequency calculation method. The results show that the obtained electric pulse sequence is feasible for modulating optical signal,thus realizing range and speed measurement of laser radar by a single shot.