IIR滤波器matlab源程序

1 IIR 滤波器滤波器 matlab 源程序源程序 1 IIR 一阶低通滤波器一阶低通滤波器 clear fi 1 fs 10 Gc2 0 9 wc 2 pi fi fs omegac tan wc 2 alpha sqrt Gc2 sqrt 1 Gc2 omegac a 1 alpha 1 alpha b 1 a 2 w 0 pi 300 pi Hw2 alpha 2 alpha 2 tan w 2 2 plot w pi Hw2 grid hold on 2 一阶高通滤波器 一阶高通滤波器 clear fi 1 fs 10 Gc2 0 5 wc 2 pi fi fs omegac tan wc 2 alpha sqrt 1 Gc2 sqrt Gc2 omegac 2 a 1 alpha 1 alpha b 1 a 2 w 0 pi 300 pi Hw2 tan w 2 2 alpha 2 tan w 2 2 plot w pi Hw2 grid hold on 3 Notch 嵌波滤波器嵌波滤波器 clear Gb2 0 5 w0 0 35 pi deltaw 0 1 pi b 1 1 tan deltaw 2 sqrt 1 Gb2 sqrt Gb2 B 1 2 cos w0 1 b A 1 2 b cos w0 2 b 1 w 0 pi 500 pi H freqz B A w plot w pi abs H grid 4 Peak 滤波器滤波器 clear 3 Ac 3 Gb2 10 Ac 10 w0 0 35 pi deltaw 0 1 pi b 1 1 tan deltaw 2 sqrt Gb2 sqrt 1 Gb2 B 1 0 1 1 b A 1 2 b cos w0 2 b 1 w 0 pi 500 pi H freqz B A w plot w pi abs H grid 5 IIR 低通滤波 低通滤波 Butterworth IIR Lowpass Use Butterworth clear fs 20 fpass 4 fstop 5 Ap 0 5 As 10 wp 2 pi fpass fs ws 2 pi fstop fs omegap tan wp 2 omegas tan ws 2 ep sqrt 10 Ap 10 1 es sqrt 10 As 10 1 4 N ceil log es ep log omegas omegap omega0 omegap ep 1 N K floor N 2 for i 1 K theta i pi N 1 2 i 2 N end for i 1 K G i omega0 2 1 2 omega0 cos theta i omega0 2 end for i 1 K a1 i 2 omega0 2 1 1 2 omega0 cos theta i omega0 2 end for i 1 K a2 i 1 2 omega0 cos theta i omega0 2 1 2 omega0 cos theta i omega0 2 end if K N 2 G0 omega0 omega0 1 a0 omega0 1 omega0 1 end w 0 pi 300 pi Hw2 1 1 tan w 2 omega0 2 N plot w pi Hw2 grid 5 6 IIR 高通滤波 高通滤波 Butterworth IIR Hightpass Use Butterworth clear fs 20 fpass 5 fstop 4 Ap 0 5 As 10 wp 2 pi fpass fs ws 2 pi fstop fs omegap cot wp 2 omegas cot ws 2 ep sqrt 10 Ap 10 1 es sqrt 10 As 10 1 N ceil log es ep log omegas omegap omega0 omegap ep 1 N K floor N 2 for i 1 K theta i pi N 1 2 i 2 N end for i 1 K G i omega0 2 1 2 omega0 cos theta i omega0 2 end for i 1 K a1 i 2 omega0 2 1 1 2 omega0 cos theta i omega0 2 end 6 for i 1 K a2 i 1 2 omega0 cos theta i omega0 2 1 2 omega0 cos theta i omega0 2 end if K N 2 G0 omega0 omega0 1 a0 omega0 1 omega0 1 end w 0 eps pi 300 pi Hw2 1 1 cot w 2 omega0 2 N plot w pi Hw2 grid 7 IIR 带通滤波 带通滤波 Butterworth IIR Bandpass Use Butterworth clear fs 20 fpa 2 fpb 4 fsa 1 5 fsb 4 5 Ap 0 0877 As 16 9897 wpa 2 pi fpa fs wpb 2 pi fpb fs wsa 2 pi fsa fs wsb 2 pi fsb fs c sin wpa wpb sin wpa sin wpb omegap abs c cos wpb sin wpb omegasa c cos wsa sin wsa omegasb c cos wsb sin wsb omegas min abs omegasa abs omegasb 7 ep sqrt 10 Ap 10 1 es sqrt 10 As 10 1 N ceil log es ep log omegas omegap omega0 omegap ep 1 N K floor N 2 for i 1 K theta i pi N 1 2 i 2 N end for i 1 K G i omega0 2 1 2 omega0 cos theta i omega0 2 end for i 1 K a1 i 4 c omega0 cos theta i 1 1 2 omega0 cos theta i omega0 2 end for i 1 K a2 i 2 2 c 2 1 omega0 2 1 2 omega0 cos theta i omega0 2 end for i 1 K a3 i 4 c omega0 cos theta i 1 1 2 omega0 cos theta i omega0 2 end for i 1 K a4 i 1 2 omega0 cos theta i omega0 2 1 2 omega0 cos theta i omega0 2 end 8 if K N 2 G0 omega0 1 omega0 a0 1 2 c 1 omega0 a0 2 1 omega0 1 omega0 end w 0 eps pi 300 pi Hw2 1 1 c cos w omega0 sin w 2 N plot w pi Hw2 grid 8 IIR 带阻滤波 带阻滤波 Butterworth IIR Bandstop Use Butterworth clear fs 20 fpa 1 5 fpb 4 5 fsa 2 fsb 4 Ap 0 5 As 10 wpa 2 pi fpa fs wpb 2 pi fpb fs wsa 2 pi fsa fs wsb 2 pi fsb fs c sin wpa wpb sin wpa sin wpb omegap abs sin wpb c cos wpb omegasa sin wsa cos wsa c omegasb sin wsb cos wsb c omegas min abs omegasa abs omegasb ep sqrt 10 Ap 10 1 es sqrt 10 As 10 1 N ceil log es ep log omegas omegap omega0 omegap ep 1 N K floor N 2 theta zeros 1 K 9 for i 1 K theta i pi N 1 2 i 2 N end G zeros 1 K a1 zeros 1 K a2 zeros 1 K for i 1 K G i omega0 2 1 2 omega0 cos theta i omega0 2 end for i 1 K a1 i 2 omega0 2 1 1 2 omega0 cos theta i omega0 2 end for i 1 K a2 i 1 2 omega0 cos theta i omega0 2 1 2 omega0 cos theta i omega0 2 end if K N 2 G0 omega0 omega0 1 a0 omega0 1 omega0 1 end w 0 eps pi 300 pi Hw2 1 1 sin w omega0 c cos w 2 N plot w pi Hw2 grid 9 IIR 低通滤波 低通滤波 chebyshev 1 IIR Lowpass Use Chebyshev Type 1 10 clear fs 20 fpass 4 fstop 5 Ap 0 5 As 10 wp 2 pi fpass fs ws 2 pi fstop fs omegap tan wp 2 omegas tan ws 2 ep sqrt 10 Ap 10 1 es sqrt 10 As 10 1 e es ep w omegas omegap N ceil log e sqrt e 2 1 log w sqrt w 2 1 a log 1 ep sqrt 1 ep 2 1 N omega0 omegap sinh a K floor N 2 theta zeros 1 K omega zeros 1 K for i 1 K theta i pi N 1 2 i 2 N end for i 1 K omega i omegap sin theta i end G zeros 1 K a1 zeros 1 K a2 zeros 1 K for i 1 K G i omega0 2 omega i 2 1 2 omega0 cos theta i omega0 2 omega i 2 11 end for i 1 K a1 i 2 omega0 2 omega i 2 1 1 2 omega0 cos theta i omega0 2 omega i 2 end for i 1 K a2 i 1 2 omega0 cos theta i omega0 2 omega i 2 1 2 omega0 cos theta i omega0 2 omega i 2 end if K N 2 G0 omega0 omega0 1 a0 omega0 1 omega0 1 else H0 sqrt 1 1 ep 2 end f 0 1 300 10 Hf2 1 1 ep 2 cheby N tan pi f fs omegap 2 plot f abs Hf2 grid 9 IIR 低通滤波 低通滤波 chebyshev 1 IIR Lowpass Use Chebyshev Type 2 clear fs 20 fpass 4 fstop 5 Ap 0 5 As 10 12 wp 2 pi fpass fs ws 2 pi fstop fs omegap tan wp 2 omegas tan ws 2 ep sqrt 10 Ap 10 1 es sqrt 10 As 10 1 e es ep w omegas omegap N ceil log e sqrt e 2 1 log w sqrt w 2 1 a log es sqrt es 2 1 N omega0 omegas sinh a K floor N 2 for i 1 K theta i pi N 1 2 i 2 N end for i 1 K omega i omegas sin theta i end for i 1 K G i 1 omega i 2 1 2 omega0 1 cos theta i omega0 2 omega i 2 end for i 1 K a1 i 2 1 omega0 2 omega i 2 1 2 omega0 1 cos theta i omega0 2 omega i 2 end 13 for i 1 K a2 i 1 2 omega0 1 cos theta i omega0 2 omega i 2 1 2 omega0 1 cos theta i omega0 2 omega i 2 end for i 1 K b1 i 2 1 omega i 1 omega i end if K N