MATLAB滤波器设计.doc

MATLAB作业 第一题 已知:h(n)={-4, 1, -1, -2,5,5,-2,-1,1,-4},参照实验内容5的程序或自编程序确定并绘出第二种线性相位滤波器的单位冲激响应h(n)和振幅响应Hr(ω). 已知:h(n)={-4, 1, -1, -2,5,0, -5, 2, 1,-1, 4},参照实验内容5的程序或自编程序确定第三种线性相位滤波器的单位冲激响应h(n)和振幅响应Hr(ω). h=[-4,1,-1,-2 ,5,0,-5,2,1,-1,4]; N=length(h);n=0:N-1; [Hr,w,c,L]=Hr_Type3(h); amax=max(c)+1;;amin=min(c)-1; subplot(2,2,1);stem(n,h); axis([-1 2*L+1 amin amax]) xlabel(n);ylabel(h(n)); title(Impulse Response) subplot(223);stem(0:L,c); axis([-1 2*L+1 amin amax]) xlabel(n);ylabel(c(n)); title(a(n)coefficients) subplot(222); plot(w/pi,Hr);grid xlabel(Frequency in pi units);ylabel(Hr) title(Type-1 Amplitude Response) subplot(224);zplane(h,1); 已知:h(n)={-4, 1, -1, -2,5,-5,2,1,-1, 4},参照实验内容5的程序或自编程序确定第四种线性相位滤波器的单位冲激响应h(n)和振幅响应Hr(ω). h=[-4,1,-1,-2 ,5,-5,2,1,-1,4]; N=length(h);n=0:N-1; [Hr,w,d,L]=Hr_Type4(h); amax=max(d)+1;;amin=min(d)-1; subplot(2,2,1);stem(n,h); axis([-1 2*L+1 amin amax]) xlabel(n);ylabel(h(n)); title(Impulse Response) subplot(223);stem(1:L,d); axis([-1 2*L+1 amin amax]) xlabel(n);ylabel(d(n)); title(a(n)coefficients) subplot(222); plot(w/pi,Hr);grid xlabel(Frequency in pi units);ylabel(Hr) title(Type-1 Amplitude Response) subplot(224);zplane(h,1); 第二题利用窗函数设计FIR滤波器2:参照实验内容7的程序或自编程序来实现 设计具有指标 ωp=0.4π, Rp=0.25dB, ωs=0.2π, As=50dB的高通数字FIR滤波器。选择合适的窗函数，确定并画出滤波器的冲激响应和频率响应。 % Highpass filter design - Hamming window wp = 0.4*pi; ws = 0.2*pi; tr_width = wp - ws; M = ceil(6.6*pi/tr_width) + 1; n=[0:1:M-1]; wc = (ws+wp)/2; hd = ideal_lp(wc,M); w_ham = (hamming(M)); h = hd .* w_ham; [db,mag,pha,grd,w] = freqz_m(h,[1]); delta_w = 2*pi/1000; Rp = -(min(db(1:1:wp/delta_w+1))) % Passband Ripple As = -round(max(db(ws/delta_w+1:1:501))) % Min Stopband attenuation % plots subplot(1,1,1) subplot(2,2,1); stem(n,hd); title(Ideal Impulse Response) axis([0 M-1 -0.1 0.3]); xlabel(n); ylabel(hd(n)) subplot(2,2,2); stem(n,w_ham);title(Hamming Window) axis([0 M-1 0 1.1]); xlabel(n); ylabel(w(n)) subplot(2,2,3); stem(n,h);title(Actual Impulse Response) axis([0 M-1 -0.1 0.3]); xlab