matlab_实现内插数字上变频 内插 低通滤波器的子程序

%***基带信号先内插再上变频。使用低通滤波器构造多相滤波器组 %***先内插时会出现I-1个0，上变频时相乘结果仍为0,。此处将本振信号按上变频后数据个数采样，然后每隔I个取一个有效结果，测试输出是否达到要求 clc; clear all; close all; j=sqrt(-1); MHz=1e+6; us=1e-6; B=50*MHz; %带宽 T=10*us; %时宽 fs=1000*MHz; %中频采样频率 f0=100*MHz; %中频频率 ts=1/fs; K=B/T; %% *******************基带LFM信号************************% fs1=100*MHz; %基带采样率 ts1=1/fs1; tsam_a=ts1:ts1:T; tsam2_a=tsam_a .^2; lfm=exp(j*2*pi*(0-B/2)*tsam_a+j*pi*K*tsam2_a); lfm_val=round((2^12)*lfm); lfm_I=real(lfm_val); lfm_Q=imag(lfm_val); % lfm_val=lfm/max(abs(lfm)); %*****************时域波形******************************% tt1=(1:length(lfm))*ts1/us; figure; subplot(1,2,1); plot(tt1,real(lfm_val)); ylabel('Real Amplitude'); xlabel('Time(us)');title('时域波形(实部) '); axis([0 max(tt1) -1.1 1.1]);grid on; subplot(1,2,2);plot(tt1,imag(lfm_val)); ylabel('Imag Amplitude'); xlabel('Time(us)'); title('时域波形 (虚部)'); axis([0 max(tt1) -1.1 1.1]); grid on;zoom xon; %********************基带信号频谱******************************% fout1=abs(fftshift(fft((lfm_val)))); fftout1=20*log10(fout1/max(fout1)); ff1=-fs1/2+fs1/length(fout1):fs1/length(fout1):fs1/2; figure; plot(ff1/MHz,fftout1,'k'); title('基带信号频谱') %,'FontName','楷体_GB2312', 'FontSize',18); xlabel('频率(MHz)','FontName','楷体_GB2312', 'FontSize',14); ylabel('归一化幅度(dB)','FontName','楷体_GB2312', 'FontSize',14); axis([-max(ff1/MHz) max(ff1/MHz) -60 3]); grid on;zoom xon; %% *******************滤波**********************% %%纹波系数为0.01dB order 99 fs=1000MHz fpass=25MHz fstop=66MHz load('FIR.mat'); %%纹波系数为0.1dB order 168 h=FIR; coeff=h; coeff=round((2^16)*coeff); wave_IQ0=floor((filter(coeff(1:10:length(coeff)),1,lfm_val)));%disp(wave_IQ0(1:10)); wave_IQ1=floor((filter(coeff(2:10:length(coeff)),1,lfm_val))); wave_IQ2=floor((filter(coeff(3:10:length(coeff)),1,lfm_val))); wave_IQ3=floor((filter(coeff(4:10:length(coeff)),1,lfm_val))); wave_IQ4=floor((filter(coeff(5:10:length(coeff)),1,lfm_val))); wave_IQ5=floor((filter(coeff(6:10:length(coeff)),1,lfm_val))); wave_IQ6=floor((filter(coeff(7:10:length(coeff)),1,lfm_val))); wave_IQ7=floor((filter(coeff(8:10:length(coeff)),1,lfm_val))); wave_IQ8=floor((filter(coeff(9:10:length(coeff)),1,lfm_val))); wave_IQ9=floor((filter(coeff(10:10:length(coeff)),1,lfm_val))); % tt2=(1:length(wave_IQ))*ts1/us; % figure(3); % plot(tt2,real(wave_IQ));title('内插滤波后时域波形(实部) '); % % fout2=abs(fftshift(fft((wave_IQ)))); % fftout2=20*log10(fout2/max(fout2)); % ff2=-fs1/2+fs1/length(fout2):fs1/length(fout2):fs1/2; % % figure(4); % plot(ff2/MHz,fftout2);title('内插滤波后频谱 '); %% *******************数字正交调制**********************% LEN=10*length(wave_IQ0); tsam=(1:LEN)*ts; LO=exp(j*2*pi*f0*tsam); %disp(LO(1:10)); LO=round((2^12)*LO); LO_I=real(LO); LO_Q=imag(LO); % figure;plot(tsam,real(LO));axis([0 max(tsam) -1.1 1.1]); % title('本振信号 '); % % fft_LO=abs(fftshift(fft(LO))); % ffft_LO=20*log10(fft_LO/max(fft_LO)); % f=-fs/2+fs/LEN:fs/LEN:fs/2; % figure;plot(f/MHz,ffft_LO);title('本振频谱 '); LO0=LO(1:10:LEN);LO1=LO(2:10:LEN);LO2=LO(3:10:LEN);LO3=LO(4:10:LEN);LO4=LO(5:10:LEN); LO5=LO(6:10:LEN);LO6=LO(7:10:LEN);LO7=LO(8:10:LEN);LO8=LO(9:10:LEN);LO9=LO(10:10:LEN); wave0= real(wave_IQ0).*imag(LO0)+imag(wave_IQ0).*real(LO0);%disp(wave0(1)); wave1= real(wave_IQ1).*imag(LO1)+imag(wave_IQ1).*real(LO1);%disp(wave1(1)); wave2= real(wave_IQ2).*imag(LO2)+imag(wave_IQ2).*real(LO2);%disp(wave2(1)); wave3= real(wave_IQ3).*imag(LO3)+imag(wave_IQ3).*real(LO3);%disp(wave3(1)); wave4= real(wave_IQ4).*imag(LO4)+imag(wave_IQ4).*real(LO4);%disp(wave4(1)); wave5= real(wave_IQ5).*imag(LO5)+imag(wave_IQ5).*real(LO5);%disp(wave5(1)); wave6= real(wave_IQ6).*imag(LO6)+imag(wave_IQ6).*real(LO6);%disp(wave6(1)); wave7= real(wave_IQ7).*imag(LO7)+imag(wave_IQ7).*real(LO7);%disp(wave7(1)); wave8= real(wave_IQ8).*imag(LO8)+imag(wave_IQ8).*real(LO8);%disp(wave8(1)); wave9= real(wave_IQ9).*imag(LO9)+imag(wave_IQ9).*real(LO9);%disp(wave9(1)); wave10=imag(wave_IQ0).*real(LO0); % wave=wave0+wave1+wave2+wave3+wave4+wave5+wave6+wave7+wave8+wave9; % wave=wave/max(abs(wave)); % % figure; % tt=(1:length(wave))*ts1/us; % plot(tt,wave0,'k'); % title('内插后中频信号波形'); % xlabel('时间(us)','FontName','楷体_GB2312', 'FontSize',14); % ylabel('归一化幅度','FontName','楷体_GB2312', 'FontSize',14); % axis([0 max(tt) -1.1 1.1]); % grid on;zoom xon; % % fout=abs(fftshift(fft(wave0))); % fftout=20*log10(fout/max(fout)); % ff=-fs1/2+fs1/length(fout):fs1/length(fout):fs1/2; % % figure; % plot(ff/MHz,fftout,'k'); % title('内插后中频信号频谱'); % xlabel('频率(MHz)','FontName','楷体_GB2312', 'FontSize',14); % ylabel('归一化幅度(dB)','FontName','楷体_GB2312', 'FontSize',14); % axis([-max(ff/MHz) max(ff/MHz) -60 3]); % grid on;zoom xon; %% ******************插值******************************% N=length(wave0); y0=zeros(1,10*N);y1=zeros(1,10*N);y2=zeros(1,10*N);y3=zeros(1,10*N);y4=zeros(1,10*N); y5=zeros(1,10*N);y6=zeros(1,10*N);y7=zeros(1,10*N);y8=zeros(1,10*N);y9=zeros(1,10*N); y0(1:10:10*N)=wave0;y1(2:10:10*N)=wave1;y2(3:10:10*N)=wave2;y3(4:10:10*N)=wave3;y4(5:10:10*N)=wave4; y5(6:10:10*N)=wave5;y6(7:10:10*N)=wave6;y7(8:10:10*N)=wave7;y8(9:10:10*N)=wave8;y9(10:10:10*N)=wave9; % y0(1:10:10*N)=wave_IQ0;y1(2:10:10*N)=wave_IQ1;y2(3:10:10*N)=wave_IQ2;y3(4:10:10*N)=wave_IQ3;y4(5:10:10*N)=wave_IQ4; % y5(6:10:10*N)=wave_IQ5;y6(7:10:10*N)=wave_IQ6;y7(8:10:10*N)=wave_IQ7;y8(9:10:10*N)=wave_IQ8;y9(10:10:10*N)=wave_IQ9; % y0(1:10:10*N)=wave9;y1(2:10:10*N)=wave8;y2(3:10:10*N)=wave7;y3(4:10:10*N)=wave6;y4(5:10:10*N)=wave5; % y5(6:10:10*N)=wave4;y6(7:10:10*N)=wave3;y7(8:10:10*N)=wave2;y8(9:10:10*N)=wave1;y9(10:10:10*N)=wave0; % y0=y0/max(abs(y0)); y1=y1/max(abs(y1)); y2=y2/max(abs(y2)); y3=y3/max(abs(y3)); y4=y4/max(abs(y4)); % y5=y5/max(abs(y5)); y6=y6/max(abs(y6)); y7=y7/max(abs(y7)); y8=y8/max(abs(y8)); y9=y9/max(abs(y9)); y=y0+y1+y2+y3+y4+y5+y6+y7+y8+y9; %disp(y(1:10)); % y=y/max(abs(y)); tt3=(1:length(y))*ts/us; figure; plot(tt3,y);title('内插后中频信号波形 '); xlabel('时间(us)','FontName','楷体_GB2312', 'FontSize',14); ylabel('归一化幅度','FontName','楷体_GB2312', 'FontSize',14); axis([0 max(tt3) -1.1 1.1]); grid on;zoom xon; fout3=abs(fftshift(fft((y)))); fftout3=20*log10(fout3/max(fout3)); ff3=-fs/2+fs/length(fout3):fs/length(fout3):fs/2; figure; plot(ff3/MHz,fftout3);title('内插后中频信号频谱 '); xlabel('频率(MHz)','FontName','楷体_GB2312', 'FontSize',14); ylabel('归一化幅度(dB)','FontName','楷体_GB2312', 'FontSize',14); axis([0 max(ff3/MHz) -60 3]); grid on;zoom xon;