中文说明：
三个复正弦信号的信噪比分别为SNR1 =30dB， SNR2 =30dB和SNR3 = 27dB。假设信号样本数为1000，FIR 滤波器的抽头个数为4。基于奇异值分解的MVDR 方法进行信号频率估计的仿真实验，获得功率谱密度函数的估计。
English Description：
The SNR of three complex sinusoidal signals are snr1 = 30dB, snr2 = 30dB and snr3 = 27db. Assuming that the number of signal samples is 1000, the number of FIR filter taps is 4. The MVDR method based on singular value decomposition is used in the simulation experiment of signal frequency estimation to obtain the estimation of power spectral density function