计算信号循环谱的函数: 这个函数用来计算数字调制信号的循环谱图,结果存放在sxf中,surf和shading interp这两个函数配合使用就可以得到信号的循环谱图,M一般取64,N取2048。需要注意的是,数字信号要保留一定的载频,不能是基带信号。 function sxf=MyCS_density(s,M,N) %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% %% %% %% %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% spe_s = fft(s,N); k = N/2-M; sxf = zeros(2*k+1,4*k+1); for ff = -k:k; 计算信号循环谱alpha截面的函数: 这个函数用来计算数字调制信号的alpha截面图,结果存放在sxf_amp中,参数的设置和上一个函数一样,需要注意的是ff参数必须是数字频率。这个函数非常简洁也非常有用,尤其是在设计基于循环谱的参数估计和调制识别算法中,一般用这个函数。 function sxf_amp = MyCSalpha_imag_density(s,M,N,ff) %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% %% %% %% %% %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% spe_s = fft(s,N); spe_s=spe_s./2; k = N/2-M; sxf_amp = zeros(1,2*k+1); for alpha=0:1:k-abs(ff)) end 计算信号循环谱f截面的函数: 这个函数和上一个函数用法差不多,主要在设计参数估计和调制识别算法中使用。 function sxf_amp = MyCSf_imag_density(s,M,N,alpha) %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% %% %% %% %% %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% spe_s = fft(s,N); spe_s=spe_s./2; k = N/2-M; sxf_amp = zeros(k+1,1); for ff = 0:k-abs(alpha/2); end |
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