%?ch5example9prog1.m
[wavfs]=wavread（‘GDGvoice8000.wav‘）;
t_end=1/fs?*length（wav）;??%?計(jì)算聲音的時(shí)間長(zhǎng)度
Fs=50000;?????????????????%?仿真系統(tǒng)采樣率
t=1/Fs:1/Fs:t_end;????????%?仿真系統(tǒng)采樣時(shí)間點(diǎn)
%?設(shè)計(jì)300Hz～3400Hz的帶通預(yù)濾波器H（z）?
[fenzifenmu]=butter（3[300?3400]/（fs/2））;
%?對(duì)音頻信號(hào)進(jìn)行預(yù)濾波?
wav=filter（fenzifenmuwav）;
%?利用插值函數(shù)將音頻信號(hào)的采樣率提升為Fs=50KHz?
wav=interp1（[1/fs:1/fs:t_end]wavt‘spline‘）;
wav_hilbert=imag（hilbert（wav））;?%?音頻信號(hào)的希爾伯特變換
fc=10000;???????????????????????%?載波頻率Hz
SSB_OUT=wav.*cos（2*pi*fc*t）-wav_hilbert.*sin（2*pi*fc*t）;?%?單邊帶調(diào)制?
figure（1）;??????????????????????%?觀察調(diào)制前后頻譜?
subplot（221）;?plot（wav（53550:53750））;?????axis（[0?200?-0.3?0.3]）;
%subplot（222）;?psd（wav?10000?Fs）;????????axis（[0?25000?-20?10]）;
subplot（223）;?plot（SSB_OUT（53550:53750））;?axis（[0?200?-0.3?0.3]）;
%subplot（224）;?psd（SSB_OUT?10000?Fs）;????axis（[0?25000?-20?10]）;
wavwrite（0.5*SSB_OUTFs‘SSB_OUT.wav‘）;??????%?將SSB調(diào)制輸出存盤(pán)備用?