徐老师讲通倍原理 编写信号处理规则 2u=m.*c; The modulated signal 2 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 Time
编写信号处理规则 u=m.*c;
徐老师饼通信原理 频谱的显示 2 [M,m,df1]=fftseq(m,ts,df); 2 M=M/fs; 2 f=[0:df1:df1*(length(m)-1)]-fs/2; 2 subplot(2,1,1); 2 plot(f,abs(fftshift(M))); Spectrum of the message signal 0.12 0.1 0.08 0.06- 0.04- 0.02 △W/W 500 -400 300 -200 .100 0 100 200 300 400 500 Frequency
频谱的显示 [M,m,df1]=fftseq(m,ts,df); M=M/fs; f=[0:df1:df1*(length(m)-1)]-fs/2; subplot(2,1,1); plot(f,abs(fftshift(M)));
徐老师讲通信原理 已调信号频谱的显示 2 [U,u,df1]=fftseq(u,ts,df); 2 U=U/fs; 2 subplot(2,1,2); plot(f,abs(fftshift(U))); 2 Spectrum of the modulated signal 0.06 0.05 0.04 0.03 0.02 0.01- OnM 500 .400 300 -200 -100 0 100 200 300 400 500 Frequency
已调信号频谱的显示 [U,u,df1]=fftseq(u,ts,df); U=U/fs; subplot(2,1,2); plot(f,abs(fftshift(U)));
徐老师讲通信原理 载波频谱的显示 2 [C,c,df1]=fftseq(c,ts,df); e C=C/fs; 2 subplot(2,1,1); 2 plot(f,abs(fftshift(C))); Spectrum of the carrier signal 80 60, 40 20 onoooo lhiMae2saadaeaaeaaeadbaeaaeaaoososlsoadaaawYniMflllhhManowasdaeaaaeae 500 -400 -300 -200 -100 0 100 200 300 400 500 Frequency
载波频谱的显示 [C,c,df1]=fftseq(c,ts,df); C=C/fs; subplot(2,1,1); plot(f,abs(fftshift(C)));
徐老师讲通信原理 噪声的产生 2 signal_power=power_x(u(1:length(u))); 2 noise_power=signal_power/snr_lin; 2 noise_std=sqrt(noise_power); noise=noise_std.*randn(1,length(u)); 2 noise sample 0.5 绿 -0.5 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 Time
噪声的产生 signal_power=power_x(u(1:length(u))); noise_power=signal_power/snr_lin; noise_std=sqrt(noise_power); noise=noise_std.*randn(1,length(u));