车辆监测用测速雷达是依据多普勒效应原理实现的。由雷达发出一束微波，遇被测目标（车辆）时微波被反射回来，再由雷达接收反射波。如果目标相对于雷达有距离上的运动，反射波的频率将与发射频率发生差异，而这种差异的大小正比于目标与雷达的相对运动速度。于是，雷达通过检测反射波频率和发射波频率的差，就可以计算出被测车辆的移动速度。本次课程设计是利用离散付里叶变换进行频谱分析，设计数字滤波器组，并对滤波器组加窗降低副瓣，通过频域方法测量速度。-Vehicle monitoring using radar gun is based on the realization of the principle of the Doppler effect. By the radar emits a microwave, in case the measured target (vehicle) when the microwave is reflected back, and then by receiving the reflected radar waves. If the target relative to the radar on a distance of motion, the frequency of the reflected wave and the emission frequency of the difference, and this difference is proportional to the relative target and radar velocity. Thus, by detecting the reflected radar wave frequency and the frequency difference between the transmitted wave, we can calculate the movement speed of the vehicle under test. This course is designed to take advantage of the discrete Fourier transform spectral analysis, digital filter design group, and filter bank windowed lower sidelobes by frequency domain methods to measure speed.