matlab数字带阻滤波器设计以及DSP设计(精)Word文档下载推荐.doc

matlab数字带阻滤波器设计以及DSP设计(精)Word文档下载推荐.doc

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rp=1;

rs=40;

wp1=0.11*pi;

wp2=0.81*pi;

ws1=0.31*pi;

ws2=0.61*pi;

%数字带阻滤波器技术指标>

wc1=（2/T）*tan（wp1/2）;

%频率预畸变>

wc2=（2/T）*tan（wp2/2）;

wr1=（2/T）*tan（ws1/2）;

wr2=（2/T）*tan（ws2/2）;

w0=sqrt（wc1*wc2）;

B=wc2-wc1;

wp=1;

%归一化通带截止频率>

ws=wp*（wr1*B）/（w0^2-wr1^2）;

%归一化阻带截止频率>

[N,wc]=buttord（wp,ws,rp,rs,'

s'

）;

%求滤波器阶数和3dB截止频率>

[Z,P,K]=buttap（N）;

[Md,Nd]=zp2tf（Z,P,K）;

%将零极点形式转换为传输形式>

[M,N]=lp2bs（Md,Nd,w0,B）;

%对低通滤波器进行频率变换，转换为带阻滤波器>

[h,w]=freqs（M,N）;

%模拟带阻滤波器的幅频响应>

xlabel（'

频率/Hz'

ylabel（'

幅度'

title（'

模拟带阻滤波器'

[b,a]=bilinear（M,N,15000）;

%对模拟滤波器双线性变换>

figure

（1）;

freqz（b,a）;

[H,W]=freqz（b,a）;

%绘出频率响应>

axis（[0,1,-100,20]）;

figure

（2）;

plot（W*fs/（2*pi）,abs（H））;

gridon;

幅值'

title（'

数字滤波器幅频响应

|H（ejOmega）|'

指标参数：

sl=0.5062rad,sl=0.5536rad,

pl=0.3750rad,pu=0.6750rad,

p=1dB,s=40dB

由MATLAB可得出系统函数系数：

Bz=[0.35210.18191.04160.35761.04160.18190.3521]

Az=[1.00000.35311.05470.30380.72320.06450.0095]

系统函数为：

H（Z）=（0.3521+0.1819*z-1+1.0416*z-2+0.3576*z-3+1.0416*z-4+0.1819*z+0.3521*z）/（1.0000+0.3531*z+1.0547*z+0.3038*z+

-4-5-60.7232*z+0.0645*z+0.0095*z）

DSP带阻源程序：

#include"

math.h"

#defineIIRNUMBER30

#defineSIGNAL1F2200

#defineSAMPLEF8000

#definePI3.1415926-5-6-1-2-3

floatInputWave（）;

floatIIR（）;

floatfAn[IIRNUMBER]=

{0.3521,0.0575735,0.649911,-0.0395743,0.0979831,-0.0727494,-0.190606,0.100419,0.113193,-0.0413053,0.00630108,-0.0526857,-0.0620213,0.0971701,0.0441409,-0.0611411,-0.00629462,-0.0124744,-0.00798267,0.0583348,-0.000312435,-0.0489819,0.0065404,0.0078924,0.00173493,0.023966,-0.0142577,-0.0264339,0.0152646,0.00930233,-0.00260476}

floatfXn[IIRNUMBER]={0.0};

floatfInput,fOutput;

floatfSignal1,fSignal2，fSignal3;

floatfStepSignal1,fStepSignal2，fStepSignal3;

floatf2PI;

inti;

floatfIn[256],fOut[256];

intnIn,nOut;

main（）

{

nIn=0;

nOut=0;

fInput=fOutput=0;

f2PI=2*PI;

fSignal1=0.0;

fSignal2=0.0;

fSignal3=0.0;

fStepSignal1=PI*0.4;

fStepSignal2=PI*0.55;

fStepSignal2=PI*0.7;

while

（1）

fInput=InputWave（）;

fIn[nIn]=fInput;

nIn++;

nIn%=256;

fOutput=IIR（）;

fOut[nOut]=fOutput;

nOut++;

//breakpoint

if（nOut>

=256）

nOut=0;

}

floatInputWave（）

{for（i=IIRNUMBER-1;

i>

0;

i--）

{fXn[i]=fXn[i-1];

fXn[0]=sin（（double）fSignal1）+sin（（double）fSignal2）+sin（（double）fSignal3）;

fSignal1+=fStepSignal1;

if（fSignal1>

=f2PI）fSignal1-=f2PI;

fSignal2+=fStepSignal2;

if（fSignal2>

=f2PI）fSignal2-=f2PI;

fSignal3+=fStepSignal3;

if（fSignal3>

=f2PI）fSignal3-=f2PI;

return（fXn[0]）;

floatIIR（）

{floatfSum;

fSum=0.0;

for（i=0;

i<

IIRNUMBER;

i++）

{fSum+=（fXn[i]*fAn[i]）;

return（fSum）;