sy31.m

数字信号处理工具箱

wp=0.3*pi;ws=0.5*pi;
Rp=1;As=50;
M=15;
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)));
As=-round(max(db(ws/delta_w+1:1:501)))
subplot(2,2,1);plot(w/pi,db);xlabel('Frequency(单位：pi）');
ylabel('|H|:(db)');grid;axis([0 1 -100 10]);
subplot(2,2,2);plot(w/pi,pha);xlabel('Frequency(单位：pi）');ylabel('phase');
subplot(2,2,3);stem(n,h);ylabel('h(n)');axis([0 M-1 -0.1 0.5])
subplot(2,2,4);stem(n,w_ham);ylabel('win-hamming');axis([0 M-1 0 1.1]);
pause;
M=45;
n=[0:1:M-1];
wc=(ws+wp)/2;
hd=ideal_lp(wc,M);
w_ham=(hamming(M))';
h=hd.*w_ham;
[db1,mag1,pha1,grd1,w]=freqz_m(h,[1]);
subplot(2,2,1);plot(w/pi,db);xlabel('Frequency(单位：pi）');
ylabel('|H|:（db)');title('M=15');grid;axis([0 1 -100 10]);
subplot(2,2,2);plot(w/pi,pha);xlabel('Frequency(单位：pi）');ylabel('phase:M=15');
subplot(2,2,3);plot(w/pi,db1);xlabel('Frequency(单位：pi）');
ylabel('|H|:（db)');title('M=45');grid;axis([0 1 -100 10]);
subplot(2,2,4);plot(w/pi,pha1);xlabel('Frequency(单位：pi）');ylabel('phase:M=45');