duoxiangjiegou.rar_8路信道化_信道化 发射机_信道化发射_多相发射机_实信号信道化

a=[1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0]; f=[2000 4000 6000 8000 10000 12000 14000 16000]; I=8;n1=400;Fs=50000;fs=Fs*2*I; for k=1:I for r=1:n1 m(k,r)=a(k)+0.8*cos(2*pi*f(k)/Fs*(r-1)); %形成各路基带信号 end end %用窗函数法设计FIR滤波器 %通带截止频率为0.0500*pi，阻带起始频率为0.0750*pi；通带最大衰减0.25dB，阻带最小衰减为50dB wp=0.0500*pi;ws=0.0750*pi; wdelta=ws-wp; %过渡带宽 N=ceil(2*pi*3.3/wdelta); N=N+72; %为满足指标，对N作修正 wc=(wp+ws)/2; %截止频率在通带和阻带边界频率的中点 n=0:N-1; alpha=(N-1)/2; %滤波器的相位延迟 s=n-alpha; hd=sin(wc*s)./(pi*s); %理想滤波器脉冲响应 win=hamming(N); %采用海明窗 hh=hd.*win'; %实际脉冲响应 [H,w]=freqz(hh); lj=abs(H); db=20*log10((lj+eps)/max(lj)); figure(3) plot(w/pi,db); title('实际幅频特性曲线(dB)'); grid on; %检验指标是否满足要求 deltaw=pi/511; rp=-(min(db(1:1:round(wp/deltaw)+1))) %检验实际的通带波动 ar=-(max(db(round(ws/deltaw):1:512))) %检验阻带最小衰减 figure(1); plot(20*log10(abs(fft(hh)))); grid on; for r=1:(N/I) for k=1:I h(k,r)=hh((r-1)*I+k); end end for r=1:n1 for k=1:I mk(k)=m(k,r); end mfft=fft(mk); for k=1:I x0(k,r)=mfft(k)*exp(j*pi/(2*I)*(k-1)); end end for r=1:n1 for k=1:I x00(k,(2*r-1))=x0(k,r); %2倍内插 x00(k,2*r)=0; end end for k=1:I for r=1:n1 x00k(r)=x00(k,r); end for r=1:(N/I) hk(r)=h(k,r); end y0=conv(x00k,hk); for r=1:n1 y0(r)=y0(r)*exp(j*pi/2*(r-1)); end for r=1:n1 y(k,r)=y0(r); % 注意 end end for k=1:I for n=1:n1*I if mod((n-1),I)==0 y00(k,n)=y(k,(n-1)/I+1); %I倍内插 else y00(k,n)=0.0; end end end for n=I:(n1*I) yout(n-I+1)=y00(1,n)+y00(2,n-1)+y00(3,n-2)+y00(4,n-3)+y00(5,n-4)+y00(6,n-5)+y00(7,n-6)+y00(8,n-7); end point=1024; yy(1:point)=yout(101:(100+point)); %注意 for n=1:point yy(n)=(yy(n)+0.001*randn)*(0.42-0.5*cos(2*pi*(n-1)/point)+0.08*cos(4*pi*(n-1)/point));%加噪声，加布拉克曼窗抑制由于信号的截断产生能量泄漏，而用FFT算法计算频谱又产生栅栏效应的影响 l(n)=fs/point*(n-1); end %输出实信号频谱 yy1=real(yy); pp1=abs(fft(yy1)); ppm1=max(pp1); figure(5); plot(l(1:512),20*log10(pp1(1:512)/ppm1)); grid on; %输出复信号频谱 pp=abs(fft(yy)); ppm=max(pp); figure(6) plot(l,20*log10(pp/ppm)); grid on;