对雷达信号进行预处理。输入设定的LFM信号，进行数字正交解调以及匹配滤波最后是相参积累。从而得到LFM信号频谱图，解调后的频谱，想干积累输出等结果。 -The radar signal preprocessing. Input set of LFM signal, digital quadrature demodulation and matched filtering the last coherent integration. LFM signal spectrum, the demod