数字信号处理大作业班级：1401012_姓名：齐翔奡_学号：14010120082输入信号的时域波形及其功率谱密度：叠加噪声后的音频信号的时域图形及功率谱密度：经过带通滤波器的音频信号的时域和功率谱密度：程序解读：clc;clearall;closeall;[wav,fs]=audioread('GDGvoice8000.wav');t_end=1/fs*length(wav);%计算声音的时间长度Fs=50000;%仿真系统采样率t=1/Fs:1/Fs:t_end;%仿真系统采样时间点%利用插值函数将音频信号的采样率提升为Fs=50KHzwav=interp1([1/fs:1/fs:t_end],wav,t,'spline');%设计300Hz～3400Hz的带通预滤波器H(z)[fenzi,fenmu]=butter(6,[3003400]/(Fs/2));nt=wgn(1,length(t),0.1);%噪声nt=nt/(max(abs(nt)));%归一化噪声wav_noise=wav+nt;%对音频信号进行滤波wav_after=filter(fenzi,fenmu,wav_noise);figure(1);subplot(2,1,1);plot(wav(53550:53750));title('语音信号时域波形');axis([0200-0.30.3]);subplot(2,1,2);psd(wav,10000,Fs);title('语音信号功率谱密度');axis([025000-2010]);figure(2);subplot(2,1,1);plot(wav_noise(53550:53750));title('加噪声后的语音信号时域波形');axis([0200-0.30.3]);subplot(2,1,2);psd(wav_noise,10000,Fs);title('加噪声后的语音信号功率谱密度');axis([025000-2010]);figure(3);subplot(2,1,1);plot(wav_after(53550:53750));title('滤波后的语音信号时域波形');axis([0200-0.30.3]);subplot(2,1,2);psd(wav_after,10000,Fs);title('滤波后的语音信号功率谱密度');axis([025000-2010]);sound(wav/max(wav),Fs);%播放解调音频sound(wav_after/max(wav_after),Fs);%播放解调音频wavwrite(demod_out,Fs,'SSBDemod_OUT.wav');%保存输出信号
