数字信号处理大作业.doc

Experiment guide book of Measurement Technology & Digital Signal Processing姓名：付 伟 明 学号：SQ10058022055专业：机械电子工程上课时间：2011-32011-61、A finite-duration sequence of length L is given as ，Determine the N-point DFT of this sequence for NL using MATLAB. (L=10, N=100)Solution：代码 幅频、相频特性曲线图：x=ones(1,10); clear;Len = 10;Num = 100;for i=1:100 x(i)=2*pi*i/Num; y(i)=(1-exp(-j*x(i)*Len)/(1-exp(-j*x(i);endMag=abs(y);Ang=angle(y);subplot(2,1,1),plot(x,Mag,.-);%subplot(2,1,1),stem(w,Mag);xlabel();ylabel(Magnitude);title(Num=100);%grid on;subplot(2,1,2),plot(x,Ang,.-);%subplot(2,1,2),stem(w,Ang);xlabel();ylabel(Phase);title(Num=100);2、, Determine the 8 and 16-point DFT using MATLAB.Solution：代码clear;Len = 4; N1 = 8;N2 = 16;for i=1:8 w1(i)=2*pi*i/N1; X1(i)=(1-exp(-j*w1(i)*Len)/(1-exp(-j*w1(i);endfor k=1:16 w2(k)=2*pi*k/N2; X2(k)=(1-exp(-j*w2(k)*Len)/(1-exp(-j*w2(k);endMag1=abs(X1);Ang1=angle(X1);Mag2=abs(X2);Ang2=angle(X2);subplot(2,2,1),stem(w1,Mag1,.-);xlabel();ylabel(Magnitude);title(N=8);grid on;subplot(2,2,3),stem(w1,Ang1,.-);xlabel();ylabel(Phase);title(N=8);grid on;subplot(2,2,2),stem(w2,Mag2,.-);xlabel();ylabel(Magnitude);title(N=16);grid on;subplot(2,2,4),stem(w2,Ang2,.-);xlabel();ylabel(Phase);title(N=16);grid on;8 and 16-point DFT3、, Determine the 8, 32 and 64-point FFT using MATLAB.Solution：代码： clear; 8, 32 and 64-point FFT 相频与幅频特性：x=1 1 1 1 1 1;N1 = 8;N2 = 32;N3 = 64;for i=1:8 w1(i)=2*pi*i/N1;endfor j=1:32 w2(j)=2*pi*j/N2;endfor k=1:64 w3(k)=2*pi*k/N2;endX1=fft(x,N1);X2=fft(x,N2);X3=fft(x,N3);Mag1=abs(X1);Ang1=angle(X1);Mag2=abs(X2);Ang2=angle(X2);Mag3=abs(X3);Ang3=angle(X3);subplot(2,3,1),plot(w1,Mag1,.-);xlabel();ylabel(Magnitude);title(N=8);grid on;subplot(2,3,4),plot(w1,Ang1,.-);xlabel();ylabel(Phase);title(N=8);grid on;subplot(2,3,2),plot(w2,Mag2,.-);xlabel();ylabel(Magnitude);title(N=32);grid on;subplot(2,3,5),plot(w2,Ang2,.-);xlabel();ylabel(Phase);title(N=32);grid on;subplot(2,3,3),plot(w3,Mag3,.-);xlabel();ylabel(Magnitude);title(N=64);grid on;subplot(2,3,6),plot(w3,Ang3,.-);xlabel();ylabel(Phase);title(N=64);grid on;4、Determine a FIR lowpass filter with N=21 by rectangular and Hamming window using MATLAB. The passband edge frequency is 0.3. Solution：代码 clear;wp=0.3*pi;N=21;win1=boxcar(N+1); % rectangularwin2=hamming(N+1); % Hammingq1=fir1(N,wp/pi,win1);q2=fir1(N,wp/pi,win2);%plot(q1);h1=freqz(q1);h2=freqz(q2);mag1=abs(h1); % Magnitudemag2=abs(h2); %w=linspace(0,wp,512);subplot(2,1,1);plot(w,mag1);grid on;title(Rectanglar);xlabel(/);ylabel(Magnitude);subplot(2,1,2);plot(w,mag2);grid on;title(Hamming);xlabel(/);ylabel(Magnitude); 5、Determine a FIR lowpass filter with N=8 and 12 by rectangular window and frequency-sampling method using MATLAB. The passband edge frequency is 0.35.Solution：代码clear;wp = 0.35*pi;N1 = 8;N2 = 12;%= rectangular =win1 = boxcar(N1+1); % rectangularwin2 = boxcar(N2+1); % rectangularq1 = fir1(N1,wp/pi,win1);q2 = fir1(N2,wp/pi,win2);%plot(q1);h1 = freqz(q1);h2 = freqz(q2);mag1 = abs(h1); % Magnitudemag2 = abs(h2); %=%= frequency sampling =%=w = linspace(0,wp,512);subplot(2,1,1);plot(w,mag1);grid on;title(N = 8);xlabel(/);ylabel(Magnitude);subplot(2,1,2);plot(w,mag2);grid on;title(N = 12);xlabel(/);ylabel(Magnitude);6、Determine a FIR Chebyshew lowpass filter that the passband edge frequency is 500Hz and the stopband edge frequency is 600Hz using MATLAB. The sampling frequency is 2000Hz, its minimum passband attenuation is 3dB and minimum stopband attenuation is 40dB.Solution：代码%Windows-based %FIR filter designa = 1;F = 500 600;Fs = 2000;Rp = 3;Rs = 40;A = 1 0; Dev = (10(Rp/20)-1)/(10(Rp/20)+1) 10(-Rs/20);n,fo,ao,w = firpmord(F,A,Dev,Fs);h = firpm(n,fo,ao,w);freqz(h,a,512,Fs);7、Determine a IIR lowpass filter using MATLAB. The passband edge frequency is 1000Hz and the stopband edge frequency is 300Hz. The sampling frequency is 1000Hz, its minimum passband attenuation is 3dB and minimum stopband attenuation is 20dB.Solution：代码clear; fp = 1000;fs = 300;F_S = 10000;T = 1/F_S;Rp = 3;Rs = 20;W1p = fp/F_S*2;W1s = fs/F_S*2;N,Wn = buttord(W1p,W1s,Rp,Rs,s);b,a = butter(N,Wn);H,w =freqz(b,a,512,F_S);plot(w,abs(H);title(Butterworth Lowpass Filter, Magnitude,order=,num2str(N);8、Determine a IIR Chebyshew I lowpass filter that the passband edge frequency is 0.2rad/s and the stopband edge frequency is 0.3rad/s using MATLAB. The passband ripple is 1dB and stopband attenuation is 16dB.Solution： 代码：% Window-based IIR DF design IIR Chebyshew I lowpass filter：% Chebyshev I lowpass filter% dsired performentswp=0.2*pi;ws=0.3*