(完整版)南理工数字信号处理课程实验报告

1、数字信号处理project实验报告学院：电子工程与光电技术学除专业：诵信工程学号： 姓名:IIR 低通滤波器设计1. 滤波器要求：Using bilinear transform methods ,design a IIR low-pass filter with the following specifications:p 0.2A , s 0.4A ; the passband ripple -0.5dB,the stopband attenuation 20dB.where A is the last nomber of your student number(1)Write a pro

2、gram to compute the required order of theButterworth or Chebyshev analog filters;(2) Using bilinear transform methods ,transform the analog filters to the corresponding digital filters;(3) Sketch the frequency response of the filters.2. 滤波器设计程序如下：wp=0.25*pi;ws=0.45*pi;Wp=tan(wp/2);Ws=tan(ws/2);ap=0.

3、5;as=20;N,Wn= cheb1ord(Wp,Ws,ap,as, 's' );B,A= cheby1(N,1,Wn, 's' );num,den= bilinear(B,A,0.5);h,w=freqz(num,den);subplot(211);plot(w/pi,20*log10(abs(h);ylim(-50 5);xlim(0 1);xlabel( 'Omega/pi' );ylabel( ' 增益(dB) ' );title('幅度响应曲线)；grid；h,w=phasez(num,den);subplot

4、(212);plot(w/pi,h/pi*180);xlabel('OmegaApi');ylabel( 'phase(degree)' );title('相位响应曲线');grid;其中，wp,ws是角频带边界频率，Wp,Ws是模拟低通滤波器的 边带角频率，ap是通带波纹，as是阻带波纹，h是频率响应。幅度相位响应波形如下:Hie Edit View Insert Tools De&ktop Window HelpQ 国 idG目 口幅度响应曲线001020.3040 50 60.70.E0 9111kli1Iil-II1111111-

5、100-200相位响应曲线0.10 20.30 40 &0 60.70 60 &1(awscd5典 dcm 0二、 FIR 低通滤波器设计1. 滤波器要求：Design a low-pass FIR filter by windowing, the specifications of the filterarefp ( 800 A) Hz, A=last two numbers of your student number；fs ( 1000+B) Hz;B=the last number of your student number； passbandripple 0.5dB

6、;min imum stopband attenuation( 40+last nomber of the student numbe) r dB; fT4kHz.Please using two different windows design the filter ,and sketch theirfrequency response.2. 滤波器设计程序如下：clear;fp=845;fs=1005;Fs=4000;as=45;wp=(fp*2*pi)/(Fs);ws=(fs*2*pi)/(Fs);wc=(wp+ws)/2;dw= ws-wp;%HammingM=ceil(3.32*pi

7、/dw);N=2*M+1;b=fir1(N,ws/(2*pi);H,w=freqz(b,1,512);figure(1);stem(b);title( ' 冲激响应' ););xlabel( 'Time-index-nylabel( 'hn');figure(2);plot(w/pi,20*log10(abs(H);grid;xlabel( 'omega/pi' );ylabel( ' 增益( dB) ' );title( ' 幅度响应' );axis(0 1 -80 10);H,w=phasez(b,1,

8、512);figure(3);plot(w/pi,H/pi*180);grid;xlabel( 'omega/pi' );ylabel( 'phase(degree)' );title( ' 相位响应' );%BlackmanM=ceil(5.56*pi/dw);N=2*M;b=fir1(N,ws/(2*pi),blackman(N+1);H,w=freqz(b,1,512);figure(4);stem(b);title( ' 冲激响应' );xlabel( 'Time-index-n' );ylabel( &#

9、39;hn');figure(5);plot(w/pi,20*log10(abs(H);grid;xlabel( 'omega/pi' );ylabel( ' 增益( dB) ' );title( ' 幅度响应' );axis(0 1 -200 10);H,w=phasez(b,1,512);figure(6);plot(w/pi,H/pi*180);grid;xlabel( 'omega/pi' );ylabel( 'phase(degree)' );title（ '相位响应'）;其中，f

10、p,fs是频带边界频率，FS是抽样频率，as是最小阻带衰 减，wc是截止频率。由于as=45所以设计时运用了 hamming窗和 blackman 窗。Hamming窗设计的滤波器频率响应波形如下:Hamming窗设计的滤波器幅度响应波形如下:Hamming窗设计的滤波器相位响应波形如下:Blackman窗设计的滤波器频率响应波形如下:Blackman窗设计的滤波器幅度响应波形如下:Figure 5File- Edit View Insert Tools Desktop Window jHelpDia a 二踮国I 度II 国2P)相聊幅度响应OBlackman窗设计的滤波器相位响应波形如下:

11、Bj Figure 6File Edit View Insert Tools Desktop Window Help-500-1000D巴盘|给黑,一是 口 口相位响应 o-1500200025003000-3500400000 10.20.3040 60.60.70 30.93H三、IIR低通滤波器设计1 .滤波器要求:specifications:0.2A , pUsing FDATool to design a low-pass IIR filter with the following0.4A ; the passband ripple -0.5dB, sthe stopband at

12、tenuation (30 A)dB.where A is the last nomber of your student number(1) Select a suitable structure ;(2) Using Butterworth or Chebyshev analog;(3) Sketch the frequency and phase response of the filters;(4) Give the impulse response hn.按照相应的要求，在FDA TOOL中填好相应的参数，就能设计 出需要的滤波器了。幅度相位波形如下：频率响应波形如下:四、FIR高通

13、滤波器设计1 .滤波器要求：Using fdatool to a high-pass FIR filter by Kaiser window, specificationsof the filter aref(3200 A) Hz, A=last three numbers of your student number;sf p (3600+B) Hz;B=the last three number of your student number ;passband ripple 0.5dB;min imum stopband attenuation (50+last number of the student number) dB;fT 20kHz.(1) Select a direct-form symmetric structure ;(2) Using Kaiser or other windows ;(3) Sketch the frequency and phase response of the filters;(4) Give the impulse response hn.同样的，按照相应的要求，在 FDA TOOL中填好相应的参数，就能设计出需要的滤波器了。幅度相位波形如下：频率响