matlab_对直扩信号采用倒谱法进行功率谱分析，检测高端周期脉冲谱线

clear all; close all; load Data; % load sig_send fs=48e3; fl=10e3; fh=14e3; B=fh-fl; f0=fl+B/2; %fs=48kHz Bandwith=4~8kHz f0=6kHz sig=resample(Data,48e3,50e3); load sig_syn corr1=corr_fun(sig(1:4e5),sig_lfm); %同步 0.8*fs根据具体信号长度选定 [~,pos_1]=max(abs(corr1)); %pos_1为接收信号中同步头的位置 t_start_1=pos_1+0.2*fs+1; sig_syn=sig(t_start_1:t_start_1+3072*10)'; %截取有用信号 % sig_syn=sig_mes; filter_n=1024; %滤波器的阶数 b=fir1(filter_n,2*2e3/fs); c=fir1(filter_n,[fl fh]/(fs/2)); sig_bandpass=filter(c,1,[sig_syn zeros(1,filter_n/2)]); sig_rec=sig_bandpass(filter_n/2+1:end); t=0:1/fs:length(sig_rec)/fs-1/fs; sig_nc1=sig_rec.*exp(1i*2*pi*f0*t); %解调 % sig_nc1=sig_rec.*real(exp(1i*2*pi*f0*t)); %解调 sig_lowpass=filter(b,1,[sig_nc1 zeros(1,filter_n/2)]); sig_nc=sig_lowpass(filter_n/2+1:end); % for i=1:length(sig_syn) % Y(i)=sig_syn(i).*sig_syn(i); % end Y=sig_rec.^2; % Sy=abs(fftshift(fft(Y))); Sy_temp=abs((fft(Y))); Sy=log10(Sy_temp); SY=abs((fft(Sy))); % for ii=1:length(SY) % C(ii)=SY(ii).*SY(ii); % end C=SY.^2; C(1:1000)=0; C(end-1000:end)=0; figure plot(C); grid on;