ÓïÒôÐźŵÄÊý×ÖÂ˲¨´¦Àí¡ª¡ª°ÍÌØÎÖ˼¡¢bartlett´°Â˲¨Æ÷Éè¼Æ
ͼ3.2ÔëÉùÐźÅʱÓòºÍƵÆ×ͼ
(2)Éè¼Æ°ÍÌØÎÖ˼µÍͨÂ˲¨Æ÷£¬MATLAB³ÌÐòÈçÏ¡£Â˲¨Æ÷ͼÈçͼ3.3Ëùʾ¡£ %µÍͨÂ˲¨
fp=3000;fs=3500;Fs=22050; rp=1;rs=10; wp=2*pi*fp/Fs; ws=2*pi*fs/Fs; Fs1=1;
wap=2*tan(wp/2); was=2*tan(ws/2);
[N,wc]=buttord(wap,was,rp,rs,'s'); [B,A]=butter(N,wc,'s'); [Bz,Az]=bilinear(B,A,Fs1); figure(4);
[h,w]=freqz(Bz,Az,512,Fs1*22050); plot(w,abs(h));
title('°ÍÌØÎÖ˹µÍͨÂ˲¨Æ÷');
xlabel('ƵÂÊ£¨HZ£©');ylabel('ºÄËð£¨dB£©'); gridon;
µÚ 9 Ò³ ¹² 56 Ò³
ÓïÒôÐźŵÄÊý×ÖÂ˲¨´¦Àí¡ª¡ª°ÍÌØÎÖ˼¡¢bartlett´°Â˲¨Æ÷Éè¼Æ
ͼ3.3°ÍÌØÎÖ˼µÍͨÂ˲¨Æ÷ͼ
3.2.2.2°ÍÌØÎÖ˼¸ßͨÂ˲¨Æ÷
(1)Ìí¼ÓµÍƵÔëÉùÐźÅzs0=0.05*cos(2*pi*100*t/22050)£¬MATLAB³ÌÐòÈçÏ¡£ÔëÉùÐźŵÄʱÓò¼°·ùƵͼÈçͼ3.4Ëùʾ¡£
t=0:length(x)-1;
zs0=0.05*cos(2*pi*100*t/22050); figure(2); subplot(2,1,1) plot(zs0)
title('ÔëÉùÐźŲ¨ÐÎ'); zs1=fft(zs0,1200);
%sound(zs,FS,bits); %»Ø·ÅÔëÒô subplot(2,1,2)
plot(f(1:600),abs(zs1(1:600))); title('ÔëÉùÐźÅƵÆ×');
µÚ 10 Ò³ ¹² 56 Ò³
ÓïÒôÐźŵÄÊý×ÖÂ˲¨´¦Àí¡ª¡ª°ÍÌØÎÖ˼¡¢bartlett´°Â˲¨Æ÷Éè¼Æ
ͼ3.4 ÔëÉùÐźÅʱÓòºÍƵÆ×ͼ
(2)Éè¼Æ°ÍÌØÎÖ˼¸ßͨÂ˲¨Æ÷£¬MATLAB³ÌÐòÈçÏ¡£Â˲¨Æ÷ͼÈçͼ3.5Ëùʾ¡£ %¸ßͨÂ˲¨
fp=600;fs=400;Fs=22050; rp=1;rs=10; wp=2*pi*fp/Fs; ws=2*pi*fs/Fs; T=1;Fs1=1; wap=2*tan(wp/2); was=2*tan(ws/2);
[N,wc]=buttord(wap,was,rp,rs,'s'); [B,A]=butter(N,wc,'high','s'); [Bz,Az]=bilinear(B,A,Fs1); figure(4);
[h,w]=freqz(Bz,Az,512,Fs1*22050); plot(w,abs(h));
µÚ 11 Ò³ ¹² 56 Ò³
ÓïÒôÐźŵÄÊý×ÖÂ˲¨´¦Àí¡ª¡ª°ÍÌØÎÖ˼¡¢bartlett´°Â˲¨Æ÷Éè¼Æ
title('°ÍÌØÎÖ˹¸ßͨÂ˲¨Æ÷');
xlabel('ƵÂÊ£¨HZ£©');ylabel('ºÄËð£¨dB£©'); grid on;
3.5 °ÍÌØÎÖ˼¸ßͨÂ˲¨Æ÷ͼ
3.2.2.3°ÍÌØÎÖ˼´øͨÂ˲¨Æ÷
(1)Ìí¼ÓµÍƵÔëÉùÐźÅ0.05*cos(2*pi*100*t/22050)£¬MATLAB³ÌÐòÈçÏ¡£ÔëÉùÐźŵÄʱÓò¼°·ùƵͼÈçͼ3.6Ëùʾ¡£
t=0:length(x)-1;
zs0=0.05*cos(2*pi*100*t/22050); figure(2); subplot(2,1,1) plot(zs0)
title('ÔëÉùÐźŲ¨ÐÎ'); zs1=fft(zs0,1200);
%sound(zs,FS,bits); %»Ø·ÅÔëÒô
µÚ 12 Ò³ ¹² 56 Ò³