【正文】 的幅頻特性在通帶或阻帶有波紋特性，可以提高選擇性；貝塞爾濾波器通帶內(nèi)有較好的線性相位特性；橢圓濾波器的選擇性相對(duì)前三種是最好的，但通帶和阻帶內(nèi)均呈現(xiàn)等波紋幅頻特性，線性特性的非線性稍重。 subplot(2,1,1)。xlabel(39。)。ylabel(39。 ws=*pi。幅度 39。 subplot(3,1,3)。 rp=1。 IIR帶通 濾波 程序如下： [y,fs,nbits]=wavread(39。 title(39。 sound(y)。濾波前信號(hào)的頻譜 39。xlabel(39。幅度 39。進(jìn)一步加深了對(duì) MATLAB 的了解。s 21 win. Michel Platini, president of European football39。s time, your ideas are always special to clear. Want, want, line is clear, as if nothing could shake his. Also once seemed to be determined to do something, but more often is he backed out at last. Dislike his cowardice, finally found that there are a lot of love, there are a lot of miss, like shadow really have been doomed. Those who do, just green years oneself give oneself an arm injection, or is a selfrighteous spiritual. 一個(gè)人的時(shí)候，自己的想法總是特別地清晰。ll be traveling fast, so despite the distance, it will not be like 鄭州輕工業(yè)學(xué)院 MATLAB 課程設(shè)計(jì)說明書 18 diving into the deep end of a pool. It will be like he is diving into the shallow end. Skydiver preps for the big jump When he jumps, he is expected to reach the speed of sound 690 mph (1,110 kph) in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he approaches the more dense air closer to Earth. But this will not be enough to stop him pletely. If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes it39。t want to give vent to out your inner voice can be in the high school children of the feelings in a period, but was eventually infarction when graduation party in the throat, later again stood on the pitch he has sweat profusely, looked at his thrown a basketball hoops, suddenly found himself has already can39。s antiracism taskforce, is in London for the Football Association39。幅度 39。xlabel(39。)。 plot(abs(S),39。 title(39。)。FIR 低通濾波器 39。 Fp=1000。)。 xlabel(39。ylabel(39。)。時(shí)間 39。 plot(y)。 sound（ y,fs,nbits） ； 回放語音信號(hào) N=length(y)； 求出語音信號(hào)的長度 Y=fft(y,N)； 傅立葉變換 調(diào)用函數(shù) y為被變換的時(shí)域系列向量， N是 DFT 變換區(qū)間長度，當(dāng) N大于 y的長度時(shí)， fft 函數(shù)自動(dòng)在 y后面補(bǔ)零，函數(shù)返回 y 的 N 點(diǎn) DFT 變換結(jié)果向量 Y。語音信號(hào)；濾波器；加噪；除噪 鄭州輕工業(yè)學(xué)院 MATLAB 課程設(shè)計(jì)說明書 2 目 錄 摘要 ......................................................................................................1 1 設(shè)計(jì)原理 ........................................................................................1 理論原理 ................................................................................1 采樣頻率 ..................................................................1 采樣位數(shù) .......................................................................1 采樣定理 .......................................................................1 時(shí)域信號(hào)的 FFT 分析 ..................................................1 數(shù)字信號(hào)的濾波器原理和方法 ...................................2 各種不同類型濾波器的性能比較 ..............................2 離散傅立葉變換 ...........................................................3 2 信號(hào)采集及讀取 ...........................................................................3 3 構(gòu)造受干擾信號(hào)并對(duì)其進(jìn)行 FFT 頻譜分析 ........................… ...6 4 數(shù)字濾波器設(shè)計(jì) ...........................................................................6 用窗函數(shù)法設(shè)計(jì) IIR 帶通濾波器 ........................................6 用窗函數(shù)法設(shè)計(jì) FIR 低通濾波器 .................................