帶通采樣以及ASKmatlab程序.doc

3軟件無線電 指導教師：楊強 報告人：張暢附錄(1)、SDR低通采樣理論%parametersfs = 5e4;%采樣頻率注意fs至少是f的2倍或2倍以上f = 5e3;%信號的頻率N = 1024;n = 1:1024; t= n/fs;deta_t = 1/fs;%采樣間隔 %signalssn = sin(2*pi*f*t);%時域采樣后的信號w = hanning(N);%加漢寧窗sn1 = sn.*w;%加窗減少頻率泄露Sn_fft = fft(sn1);%頻域信號Sn = abs(Sn_fft); %figuresfigure(1);plot(t,sn);title(s(n)的時域波形);grid on;xlabel(t);xlim(0 0.021);ylabel(幅度);figure(2);xax = -N/2:N/2-1/N*fs/1000;%將f軸單位變?yōu)閗Hzplot(xax,20*log10(fftshift(Sn);title(s(n)的頻域波形);grid on;xlabel(f(kHz);ylabel(幅度(dB);ylim(-200 100);(2)、SDR帶通采樣理論%parametersf = 1.3e3;%基頻fo = 100e6;%載波頻率N = 1024;n = 1:1024;fs = 4e3;%采樣頻率t= 0:0.001:2;st = cos(2*pi*(f+fo)*n/fs);%帶通抽樣信號St1 = fft(st);St = abs(St1); st0 = cos(2*pi*(f+fo)*t);St0 = fft(st0);St2 = abs(St0); figure(1);plot(n,st);title(帶通抽樣信號時域圖像);xlabel(n);xlim(0 1026);ylabel(幅度);grid on; figure(2);plot(t,st0);title(帶通原始信號時域圖像);xlabel(t);ylabel(幅度);grid on; figure(3);xax =-N/2:N/2-1/N*fs/1000;plot(xax,20*log10(fftshift(St);title(帶通信號抽樣后頻域圖像);xlabel(f(kHz);ylabel(幅度(dB);grid on;(3)、頻率調制信號%頻率調制%parametersfs = 1e3;%抽樣頻率ts = 1/fs;%采樣率N = 1024;n = 0:1:N-1;t = n/fs;kf = 100.1;A = 100;Aw = 10;fc = 10000;%載波頻率fm = 10;%調制信號頻率mf = kf*Aw/(2*pi*fm);%signalss1 = A*cos(2*pi*fc*t).*cos(mf*sin(2*pi*fm*t);s2 = A*sin(2*pi*fc*t).*sin(mf*sin(2*pi*fm*t);s = s1-s2;%頻率調制信號S0 = fft(s);S1 = fftshift(S0);S_0 = abs(S1);%figuresfigure(1);plot(t,s);title(頻率調制信號時域圖像);xlim(0,0.5);xlabel(t(s);ylabel(幅度);grid on;figure(2);xax = -N/2:N/2-1/N*fs/1000;plot(xax,20*log10(S_0);title(頻率調制信號頻域圖像);xlabel(f(kHz);ylabel(幅度(dB);grid on;(4)、幅度調制信號、DSB信號、USB信號%parametersclear all;clc;close all;fs = 1e3;%抽樣頻率ts = 1/fs;%采樣間隔N = 10000;n = 1:N;t = n/fs;ma = 0.5;fc = 200;%載波頻率x = cos(2*pi*fc*t);%生成載波fm = 1;%調制信號頻率m = cos(2*pi*fm*t);%基帶信號%signalss = (1+ma*m).*x;%幅度調制信號s1= m.*x;%雙邊帶信號DSBs2 = cos(2*pi*(fc+fm)*t);%SSB信號中的USBS1 = fft(s);S_1 = abs(S1);S2 = fft(s1);S_2 = abs(S2);S3 = fft(s2);S_3 = abs(S3);%figuresfigure(1);plot(t,s);title(幅度調制信號時域圖像);xlim(0 1.5);xlabel(t(s);ylabel(幅度);grid on;figure(2);xax = -N/2:N/2-1/N*fs/1000;plot(xax,20*log10(fftshift(S_1);title(幅度調制信號頻域圖像);xlim(0.19 0.21);xlabel(f(kHz);ylabel(幅度(dB);grid on;figure(3);plot(t,s1);title(雙邊帶調制信號時域圖像);xlim(0 1.5);xlabel(t(s);ylabel(幅度);grid on;figure(4);xax1 = -N/2:N/2-1/N*fs/1000;plot(xax1,20*log10(fftshift(S_2);title(雙邊帶調制信號頻域圖像);xlim(0.19 0.21);xlabel(f(kHz);ylabel(幅度(dB);grid on;figure(5);plot(t,s2);title(USB調制信號時域圖像);xlim(0 1.0);xlabel(t(s);ylabel(幅度);grid on;figure(6);xax1 = -N/2:N/2-1/N*fs/1000;plot(xax1,20*log10(fftshift(S_3);title(USB調制信號頻域圖像);xlim(0.19 0.21);xlabel(f(kHz);ylabel(幅度(dB);grid on;(5)、2ASK信號%2ASK信號的時域和頻域分析clear all;clc;close all;%清除一切。m = 1 1 1 0 0 0 1 0 1 1 0 1;%數(shù)字信號的序列（自己隨便產生的）Lm = length(m);%序列的長度F = 200;%數(shù)字信號的帶寬(1或0的帶寬是200Hz)f = 800;%正弦載波信號的頻率A = 1;%載波的幅度Q = f/F;%頻率比，即一個碼元寬度中的正弦周期個數(shù)M = 500;%一個正弦周期內的采樣點數(shù)t = (0:M-1)/M/f;%一個正弦信號周期內的時間%signalscarry1 = repmat(A*sin(2*pi*f*t),1,Q);%一個碼元寬度內的正弦載波信號Lcarry1 = length(carry1);%一個碼元寬度內的信號長度carry2 = kron(ones(size(m),carry1);%載波信號ask = kron(m,carry1);%調制后的ASK信號N = length(ask);%ASK信號的長度tau = (0:N-1)/(M-1)/f;%時間Tmin = min(tau);%最小時間Tmax = max(tau);%最大時間T = ones(size(carry1);%一個數(shù)字信號1dsig = kron(m,T);Ask = fft(ask);Ask0 = abs(Ask);%imagesfigure(1);plot(tau,dsig);grid on;axis(Tmin Tmax -0.2 1.2);title(數(shù)字信號序列的圖像);figure(2);plot(tau,carry2);xlim(0 0.06);grid on;title(載波時域圖像);figure(3);plot(tau,ask);grid on;axis(Tmin Tmax -1.2*A 1.2*A);title(2ASK信號的時域圖像);figure(4);xax = -N/2:N/2-1/N*Lm*F;plot(xax,20*log10(fftshift(Ask0);xlim(-300 300);title(2ASK信號的頻域圖像);grid on;(6)、16路信道化發(fā)射機%parametersclc;close all;clear all;a = 1;%幅度fs = 50;%內插前采樣頻率k = 1:16;%16路信號I = 16;%內插系數(shù)N = 1024;fk = 1:1:N;sk = zeros(16,N);%創(chuàng)建16行N列的零矩陣用來存放16路時域信號Sk = zeros(16,N);%創(chuàng)建16行N列的零矩陣用來存放16路頻域信號for k = 1:16 sk(k,:) = a*(1+0.5*exp(j*2*pi*k*fk/fs);%輸入16路時域信號endfor k = 1:16 Sk(k,:) = fft(sk(k,:);%16路信號頻域endfigure(1);xax = -N/2:N/2-1/N*fs;plot(xax,20*log10(abs(fftshift(Sk(:,1:N);title(16原始復信號時域疊加圖);xlabel(f(Hz);xlim(-5 25);ylabel(幅度);figure(2);h0 = fir1(265,0.5);HW = fft(h0,N);xax1 = -N/2:N/2-1/N*fs;plot(xax1,10*log10(abs(fftshift(HW);title(濾波器響應);xlabel(f(Hz);ylabel(幅度);%I倍內插，即16倍內插，此時fs變大N_1 = N*16;st = zeros(16,N_1);St = zeros(16,N_1);for k = 1:16 for g = 0:N-1 st(k,g*I+k) = sk(k,g+1); endendsum = zeros(1,N_1);for k = 1:16 sum = sum+st(k,1:N_1);endfor k = 1:16 St(k,:) = fft(sum(1,1:N_1);endfor k = 1:16 St(k,1:N) = St(k,1:N).*HW;endfigure(3);x