功率谱密度，主要求 功放预失真补偿前后的功率谱密度-Power spectral density, mainly for power amplifier predistortion compensation before and after the power spectral density

预失真补偿后的图形,采用快速傅里叶变换（Fast Fourier Transform, FFT） 计算得信号的频率数据，再利用得到的频率数据计算功放预失真补偿前后功率谱密度 样值-Predistortion compensation of graphics, using the Fast Fourier Transform, Fast Fourier Transform and FFT) Calculate signal frequency data, then get the fr