第 8 章 数字信号处理典型算法程序设计
Post on 02-Jan-2016
114 Views
Preview:
DESCRIPTION
TRANSCRIPT
PowerPoint Presentation
FIR: : FIR FIRS XmemYmemPmad PmadPAR (RC)0 ((Xmem)(Ymem))16A (B)(A(3216))PARB (PAR1)PAR (RC)1RC
*AR1+% 202 520N=5EFB550EFB=1000h20BKAR1 1000hAR1step = +1index19(13h)index = index + stepindexBK20index = index + step BKindex=0AR1=1000hEFB EOBEFB3.2.5 2 N208 8.1 DSP
8 8.1.1f(t)h(t)
f(t)h(t)8 8.1.2 1.
f(k)
8
12301238 2.
,
8 3. 8 8.1.3.C54x 1.C54xdsplib TIC54xDSPLIBCCSDSPLIB C 8 DSPLIB oflag = short convol (DATA *x, DATA *h, DATA *r, ushort nr, ushort nh)xhr
8 , 0 j nr x hxL+M-1hMnrL+M-1rM-1
12Each section can be convolved with the finite- length impulse response and output sections are fitted together in an appropriate way.Block ConvolutionIf the input signal is of indefinite duration, the input signal to be processed is segmented into sections of length L.The processing of each section can then be implemented using the DFT.
13Block Convolution
overlap-add method (1)Segment into sections of length L;
(2) fill 0 into and some section of , do() L+P-1 points FFT ;
(3) calculate 14
P-1 points(4)add the points n=0P-2 in yr[n] to the last P-1 points in the former section yr-1[n]the output for this section is the points n=0L-1
overlap-add method
L=16(1)Segment into sections of length L;
(2) fill 0 into and some section of , then do L+P-1 points FFT ;
(3) calculate
1415
Circular Convolution as Linear Convolution with Aliasing
input16
overlap-save method (4) the output for this section is L-P+1 points of y[n] n=P-1,L-1
(1) segment into sections of length L, overlap P-1 points;
(2) fill 0 into and some section of , then do L points FFT
(3) calculate
L=25L-P+1 P-1pointsP-1pointsP-1pointsP-1+L8 C#define Frame 240 //nr#define FilterLength 8 //nhfor(i=0;i VECT PAGE 0 fir_coff :> EPROGPAGE 0 fir_bfr :>IDATA1PAGE 1 fir_vars :>IDATA1PAGE 1STACK :> EDATAPAGE 1} 8 15FIR0.6CCSFIRCCSfir.pjtfir.asm,vectors.asm fir.cmdfir.pjtprojectrebuild all file load program fir.out DSP
8 MATLABCCS1clear allx(1:20)=0x(2:2:1000,:)=400x=x'x=x(:)fid1=fopen('rec.dat','wt')fprintf(fid1,'1651 1 0 0 0\n');% a1=fprintf(fid1,'%d\n',x)fclose(fid1)
8 MATLABCCS1clear allx(1:20)=0x(2:2:1000,:)=400x=x'x=x(:)fid1=fopen('rec.dat','wt')fprintf(fid1,'1651 1 0 0 0\n');% a1=fprintf(fid1,'%d\n',x)fclose(fid1)
CCS.dat 1651 1 3000 0 C8MagicNumber16511- 2- 3- 4- 0x3000 0- 1- 0xC8(200)8 MATLABCCS2)File->Data->LoadMatlab rec.dat
3)AddressinputLengthC8200dPagedata4), Run8 5 viewgraph/time frequence
8 5) viewgraph/time frequence
8 5) viewgraph/time frequence
8 5) viewgraph/time frequence
8 8.3 IIRDSP IIR 8.3.1 IIR1. IIRIIR
8 IIR M=Nz
8 IIR
IIR (1)I()(2)II()(3)()(4)(5)(lattice)
8 2. IIR1)IIR
IIRIIRIIR
8 IIIR
8 IIIR
8 IIIIR x(n)y(n)w(n)- a1- a2b1b2
b0
8 2)IIRIIR :
Hi(z) 107Direct Form II
x[n]y[n]w[n]b0b1b2bN-1bNa1a2aN-1aNz1z1z1
108 (Cascade Form)
109Cascade Form
2nd OrderSystem2nd OrderSystem2nd OrderSystem110Cascade Form
x[n]y[n]z1z1a11a21b11b21b01z1z1a12a22b12b22b02z1z1a13a23b13b23b03123Assume Ns=38 : x(n)y(n)Hk(z)H1(z)CH2(z)IIR :
8 IIR: H2 (z)x(n)y(n)H1(z)Hk(z)C8 :
:IIR
8 IIR: yi(n)yi-1(n)ei(n)ei-1(n)-kiki
18 3. IIR 1
2,
3 8
1
2:
8 sjz
sz
sz 8
c s/ cs 8 (1)(2) 8 (1)
(2)Ha(s),s/ cHa(s)sH(s) 8 (3)H(s)H(z)H(s)H(z)
(2)(3)8
8 8-1BW=1rad/sfs=100Hz
= BW=1 rad/sT=1/ fs=0.01s
c
8 s/ c
s z
8 8-1BW=1rad/sfs=100Hz
= BW=1rad/sT=1/ fs=0.01s
c
8 s/ c
s z
8 8.3.2 IIRC54x 1.1)butter
[b,a] = buttern,Wn [b,a] = buttern,Wn,ftype Wnn0Wn1Wn=10.5fs 8 ftype = highWn
ftype = stopWn = [ W1 W2]W1< W
top related