FIR Project

MC LC

Phn Trang

Li m u ...................................................................................................................... 2

Li cm n ........................................................................................................................ 3

I. Yu cu b lc v l thuyt tng qut ........................................................................ 4

1. Yu cu v b lc FIR ......................................................................................... 4

2. L thuyt b lc FIR ............................................................................................ 4

II. M phng MATLAB v vit chng trnh CCS ..................................................... 10

1. M phng Matlab bi ton b lc FIR ............................................................... 10

2. Yu cu phn mm v phn cng ...................................................................... 14

3. Vit chng trnh trn CCS 6.1 ......................................................................... 16

III. Kt qu ....................................................................................................................... 23

IV. Ti liu tham kho .................................................................................................... 24

Bo co bi tp ln X l tn hiu tng t v s GVHD: PGS.TS L Tin Thng Nhm 1

2

LI M U

X l tn hiu s (Digital Signal Processing DSP) tr thnh mn hc c s cho nhiu

ngnh khoa hc, k thut: in- in t, Vin thng,Trong , php x l c bn nht

ca DSP l lc, v cc h thng c cp n nhiu nht trong x l tn hiu s l cc

b lc s (Digital Filter). Nu xt v p ng xung c th chia cc b lc s thnh 2 loi

chnh l b lc c p ng xung hu hn FIR (Finite Impulse Response) cn gi l lc

khng quy, v b lc c p ng cung v hn IIR (Infinite Impulse Response) cn gi

l lc quy. Xt v p ng tn s bin c th chia cc b lc, FIR hay IIR, thnh 4

loi c bn: thng thp, thng cao, thng di v chn di. Cc b lc ny c th c thit

k bng nhng phng php sau y: phng php ca s ( Window Design Techniques),

phng php ly mu tn s (Frequency Sampling Design Techniques) v phng php

xp x ti u cn bng gn sng (Optimal Equiripple Design Techniques).

Trong bo co bi tp ln ny, nhm xin php c trnh by vic thit k b lc thng

thp FIR bc 3 thc hin trn phn cng TMS320C5515 ca Texas Instrument (TI)

nm vng l thuyt v b lc FIR cng nh lm quen vi KIT TMS320C5515 v cc phn

mm h tr Code Composer Studio (CCS), MATLAB


3

LI CM N

Trn thc t khng c s thnh cng no m khng gn lin vi nhng s h tr, gip

t hay nhiu, d trc tip hay gin tip ca ngi khc. Trong sut thi gian thc hin bo

co ny, nhm em nhn c s quan tm, gip ca qu Thy c v bn b.

Vi lng bit n su sc nht, nhm xin chn thnh cm n PGS.TS L Tin Thng

hng dn nhm trong vic tip cn n cc vn X l s tn hiu hon thnh bo

co ny.

Project c thc hin trong gn sut hc k 2, bc u gip nhm tm hiu thm v

mt s kin thc cn hn ch v cn nhiu b ng. Do vy, khng trnh khi nhng thiu

st l iu chc chn, nhm rt mong nhn c nhng kin ng gp qu bu ca qu

Thy c v cc bn hc cng lp nhng kin thc ca nhm trong lnh vc ny c

hon thin hn.


4

I. Yu cu b lc v l thuyt tng qut

1. Yu cu v b lc FIR

Trong project ny, yu cu thit k b lc thng thp FIR bc 3, c tn s ct =3000.

Thit k trn KIT TMS 320C5515.

2. L thuyt b lc FIR

Cc h thng LTI ri rc c th phn loi thnh h thng FIR ( Finite Impulse Response)

v IRR ( Infinite Impulse Response), l n c p ng xung h(n) hu hn hay v hn.

Trong bi bo co ny, ta ch cp n b lc FIR.

y l dng b lc c p ng xung h(n) c gi tr trn khong thi gian hu hn 0 v bng 0 cc gi tr khc:

= {0, 1, 2, , , 0,0,0, . }

trong M c xem nh l bc ca b lc. Tng ng vi n, chiu di ca vector p

ng xung ca b lc FIR = {0, 1, 2, , } l = + 1.

Cc h s ca p ng xung {0, 1, 2, , } c gi theo nhiu cch khc nhau h s lc ( filter coeficients, filter weights, hay filter taps).

Ta bit y(n) l tch chp (convolution) ca chui u vo x(n) vi chui b lc h(n),

c vit di dng:

() = (0)() + (1)( 1) + (2)( 2)

Hay vit rt gn li l:

() = ()( ) ()

V vy vi b lc FIR, c phng trnh n gin nh sau:

() = ()( )

=0

Hay khai trin ra l:

() = 0() + 1( 1) + + ( )

Nh vy, phng trnh I/O nhn c t tng c trng s ca cc mu u vo hin to v

M mu trc ( 1), ( 2), , ( )


5

V mt l thuyt, da trn c im ca p ng tn s, x l tn hiu s quan tm n 4

loi b lc l tng sau y:

a. B lc thng thp l tng

p ng bin - tn s : |()| = {

1, || 0,

Khi p ng xung ca b lc thng thp l tng vi tr nhm l:

() =

sin( )

b. B lc thng cao l tng

p ng bin - tn s : |()| = {

1, || 0,


() = ( )

sin( )

c. B lc thng di l tng

p ng bin - tn s : |()| = {

1, 1 || 20 ,


() = 2

sin2( ) 1

sin1( )

d. B lc chn di l tng

p ng bin - tn s : |()| = {

0, 1 || 21 ,


() = ( ) 2

sin2( ) +1

sin1( )

Chng ta c nhn xt l p ng cung ca cc b lc l tng ni trn c chiu di v hn,

xut pht t ch s n +, v khng nhn qu, dn n khng th thc hin c v mt vt l. Khi tng hp b lc thc t, ta phi chp nhn p ng xung phi xut pt t

ch s 0 p ng iu kin nhn qu. Khi , p ng tn s ca b lc thc t c phn

qu t di thng n di chn, hoc ngc li, v c gi l di chuyn tip (transition


6

band). ng thi phi c s gn sng (ripple) c di thng v di chn hoc t nht ti

mt trong hai, di thng hoc di chn.

Vic thit k b lc l qu trnh tm ra cc tham s, hay dy p ng xung ca b lc, tha

mn cc yu cu ch tiu k thut cho trc, c th l mt s hoc tt c cc tham s tuyt

i (absolute specification) sau:

Tn s ct di thng

Tn s ct di chn

gn sng di thng 1

gn sng di chn 2

Trn thc t, cc tham s thng c cho di dng tng i(relative specification) tnh

theo n v decibels di dng sau y:

gn sng di thng theo dB c tnh bng cng thc:

= 20 log1 11 + 1

[]

suy gm di chn theo dB c tnh bng cng thc:

= 20 log2

1 + 1[]

B lc FIR c mt s u im v mt thc hin nh sau:

- p ng pha l tuyn tnh

- Tng i d thit k v lun lun l h thng n nh

- Thc hin c vi hiu qu cao

- C th thc hin c trn c s p dng bin i Fourier ri rc

Hm p ng pha - tn s ca b lc FIR c dng sau:

() = , ,

V hm p ng tn s ca b lc FIR c cho di dng ln v pha nh sau:

() = () , ()

Da trn tnh cht i xng hay phn i xng ca dy p ng xung v chiu di N ca

dy p ng xung, ngi ta phn loi b lc FIR lm 4 loi sau y:

a. B lc FIR loi 1:

h(n) i xng, N l, = 0, = 1

2


7

() =

[ ()

12

=0]

12

vi (0) = (1

2) , (

1

2)

() = 2 ( 1

2 ) , 1

1

2

dn n: () = ()1

2=0 , () =

1

2

b. B lc FIR loi 2:

h(n) i xng, N chn, = 0, =

2

() =

[ ()cos (

1

2)

2

=0]

12

vi () = 2 (

2 ) , 1

2

dn n: () = ()cos ( 1

2)

2=0 , () =

1

2

c. B lc FIR loi 3:

h(n) i xng, N l, =

2, =

1

2

() =

[ ()

12

=0] (

2

12 )

vi () = 2 (1

2 ) , 1

1

2

dn n: () = ()1

2=0 , () =

2

1

2


8

d. B lc FIR loi 4:

h(n) i xng, N chn, =

2, =

2

() =

[ ()sin(

1

2)

2

=0] (

2

12 )

vi () = 2 (

2 ) , 1

2

dn n: () = ()sin( 1

2)

2=0 , () =

2

1

2

C 3 phng php tng hp b lc FIR pha tuyn tnh, l: Phng php ca s. Phng php ly mu tn s Phng php lp

Trong phn ny ta xt phng php thit k da trn phng php ca s.

T tng c bn ca phng php ca s l tm ra p ng xung ca b lc l tng

risau ct xn hai u ( hay nhn vi mt hm ca s) dy p ng xung sao cho

ta thu c mt b lc FIR pha tuyn tnh, ng thi l nhn qu. im nhn mnh

phng php ny l tm ra p ng xung thch hp ca b lc l tng v la chn hm

ca s thch hp. V mt l tng, b lc thng thp l tng pha tuyn tnh c li di

thng bng 1 v p ng tn s bng 0 trn ton di chn, tc l:

() = {

, || 0 ,

, vi

Th ta s thu c dy p ng xung

() =

sin( )

C tnh cht i xng ti

Vi cc b lc s l tng khc, bao gm thng cao, thng di, v chn di, dy ca p

ng xung cng c dng tng t nh vy v c th suy ra t dng p ng xung ca b lc

thng thp l tng ni trn.

thu c p ng xung ca b loc FIR v mt thc t, phng php ca s dng k

thut nhn hm p ng xung ca b lc l tng () vi mt hm ca s w(n), vi


9

w(n) l mt hm i xng vi trong khong t 0 n N-1 v bng 0 trong khong cn

li. Kt qu l hm p ng xung ca b lc thc t h(n) l i xng hoc phn i xng

vi = 1

2 trong khong [0,N-1].

Cc ca s thng dng:

Ca s ch nht Ca s tam gic Ca s Hamming Ca s Hanning Ca s Blackman Ca s Kaiser


10

II. M phng MATLAB v lp trnh trn CCS

1. M phng Matlab bi ton b lc FIR

Trc khi thit k b lc FIR da trn yu cu t ra, nhm thc hin thit k b lc FIR

trn Matlab bng cng c fdatool ca n. Sau tin hnh m phng trn Simulink da

vo b lc FIR c thit k vi mt s mu tn hiu.

Tng quan v cng c thit k b lc s FDATool

Cng c thit k b lc s (FDATool) cung cp cho ta nhng k thut in tin thit k,

phn tch, m phng cc b lc s. N cho php nng cao kh nng x l h thng trong

thi gian thc nh vi b lc thch nghi, b lc a nhim v s chuyn i gia chng.

hp cng c h tr thit k b lc FIR gm:

+ Tramg b cho thit k b lc FIR bao gm cc chc nng gim thiu v th t, v gn

song, v pha, v bang k bn, v im n bang, li xp x, song hi v gn song ln

nht ca thit k.

+ Thit k vi b lc FIR gn nh, ti u vi nhng thit k pha phi tuyn v gim thiu

c li.

+ Thit k b lc FIR na bng tn c trang b bao gm: phng php ca s, phng

php hnh vung

Tin hnh thit k b lc FIR vi fdatool

+ G lnh >>fdatool trn command window, hin ra ca s lm vic Filter Design &

Analysis Tool.

+ Trong ca s lm vic, thit k b lc FIR theo yu cu, s dng phng php ca s

(Design/Window)


11

Hnh 1. B lc thng thp FIR dng phng php ca s trong Design v Response

Hnh 2. Chn bc b lc trong Filter v s dng ca s hnh ch nht bng cch chn

Rectangular Window trong Options


12

Hnh 3. Trong Frequency chn Fc- tn s ct ca b lc FIR v tn s ly mu- Fs

Cui cng, nhn Design Filter hon thnh vic thit k b lc.

Ta thy p ng tn s ca b lc hin th trn ca s Filter

Hnh 4. p ng tn s ca b lc hin th trn ca s Filter

V p ng xung ca FIR c xut ra bng cch chn File/ Export

Trong Command Window s hin ra bng Num cha cc gi tr ca h(n)


13

Hnh 5. Cc gi tr ca h(n)

Do vy, ta c () = {0.2406, 0.2594, 0.2594, 0.2406}

Da vo thit k b lc FIR trn, m phng bng code Matlab nh sau

Tn hiu u vo ( ) 5sin(1000 ) 3 os(4000 ) 6sin(20000 ) 8cos(32000 )x t t c t t t

f1=500; f2=2000; f3=10000; f4=16000; fs=40000; T=1/fs; L=1000; t=(0:L-1)*T;

NFFT = 2^nextpow2(L); x=5*sin(2*pi*f1*t)+3*cos(2*pi*f2*t)+6*sin(2*pi*f3*t)+8*cos(2*pi*f4*t); X=fft(x,NFFT)/L; f=fs/2*linspace(0,1,NFFT/2+1); subplot(2,2,1); plot(f,2*abs(X(1:NFFT/2+1))); title('Input signal X(t)'); xlabel('f[Hz]'); ylabel('Magnitude of X(t)');

h4=[0.2406 0.2694 0.2594 0.2406]; y=conv(x,h4); Ly=L+length(h4)-1; NFFTy=2^nextpow2(Ly); Y=fft(y,NFFTy)/Ly; fy=fs/2*linspace(0,1,NFFTy/2+1); subplot(2,2,2); plot(fy,2*abs(Y(1:NFFTy/2+1))); title('Output signal Y(t) after X(t) pass throw Lowpass FIlter 3kHz');

xlabel('f[Hz]'); ylabel('Magnitude of Y(t)');


14

Ph bin ca tn hiu u ra v u vo nh sau

Hnh 6. Ph bin ca tn hiu vo v ra

Cho thy vi b lc thng thp FIR tn s ct 3kHz, ti cc tn s cao 10kHz v 16kHz

u b trit tiu gn nh hon ton. V vy c th s dng b lc FIR h = {0.2406, 0.2694,

0.2594, 0.2406}.

2. Yu cu phn mm v phn cng

Phn mm v phn cng

Cc phn mm v phn cng cn thit cho bi tp ln bao gm

B TMS320C5515 eZdsp USB Stick Development Tool do TI sn xut

Phn mm giao tip gia PC vi b KIT Code Composer StudioTM (CCS)

Phn mm tnh ton MATLAB ( thc hin vic m phng)

My tnh Laptop, USB, phn mm h tr pht song.

Gii thiu v KIT TMS320C5515 eZdsp USB Stick Development Tool

Hnh 7. KIT TMS320C5515 eZdsp USB Stick Development Tool


15

Cc thnh phn chnh ca b KIT

C55x CPU v cc b nh lin quan

Phn cng tng tc FFT

Bn b iu khin DMA v giao din b nh bn ngoi

Module qun l in

Cc thit b ngoi vi I/O bao gm I2S, I2C, SPI, UART, Timers, EMIF, 10 bit SAR

ADC, iu khin LCD, USB 2.0.

Hnh 8. S khi chc nng b KIT

Phn mm giao tip gia PC vi b KIT Code Composer StudioTM (CCS)


16

Hnh 9. Phn mm giao tip gia PC vi b KIT Code Composer StudioTM (CCS)

Code Composer Studio l mi trng pht trin tch hp c TI xy dng nhm h tr

khch hng trong vic tip cn v pht trin ng dng vi cc sn phm ca TI. IDE ny

c mi trng lm vic kh thn thin, c kt hp vi Programer v Debugger.

3. Lp trnh trn CCS 6.1

Trong project ny, nhm s dng tn hiu u vo nh trn

( ) 5sin(1000 ) 3 os(4000 ) 6sin(20000 ) 8cos(32000 )x t t c t t t

V c to ra t matlab nh sau

f1=500; f2=2000; f3=10000; f4=16000; fs=40000; T=1/fs; L=1000; t=(0:L-1)*T;

% Tao tin hieu x(n) cac tan so f1, f2, f3, f4 x=5*sin(2*pi*f1*t)+3*cos(2*pi*f2*t)+6*sin(2*pi*f3*t)+8*cos(2*pi*f4*t);

% Tao file du lieu vao dang binary id = fopen('F:\Project\x.bin','wb'); fwrite( id, x, 'float') ; fclose(id) ;


17

Sau khi chy trong matlab, nhm c file x.bin lm ng vo ca KIT TMS320C5515.

Trong CCS 6.1, to Project mi lp trnh cho KIT vi cc thng s b FIR tn s ct

3kHZ nh trn:

h = {0.2406, 0.2694, 0.2594, 0.2406}

Trong main.c

#include

#include

#include "usbstk5515.h"

#include "convolution.h"

#include "overlap.h"

#define M 3

#define Lx 1000

int main( void )

{

float h[M+1] = { 0.2406, 0.2694, 0.2694, 0.2406 } ;

float *x , *y, *ytemp ;

x = ( float* ) malloc( Lx * sizeof ( float* ) ) ;

y = ( float* ) malloc( ( M + Lx )* sizeof ( float* ) ) ;

ytemp = ( float*) malloc( M * sizeof ( float* ) ) ;

if( ( x == NULL ) || ( y == NULL ) || ( ytemp == NULL ) )

{

printf(" Error : Memory full \n") ;

exit ( 1 ) ;

}

overlap( M, h, Lx, x, y, ytemp ) ;

printf(" OK \n " ) ;

return 0 ;

}


18

Trong overlap.c

#include

#include

#include "overlap.h"

#include "usbstk5515.h"

#include "convolution.h"

void overlap( unsigned short M, float *h ,

unsigned short Lx, float *x ,

float *y , float *ytemp )

{

FILE *pfile_in, *pfile_out ; // open files input

and output

Uint8 *pdata_in, *pdata_out ; // buffer_data

Uint32 i, k ; // count var

Uint32 *p_y_Uint32 = ( Uint32* )y ,tempt ; // tranmitter

Uint32 *p_x_Uint32 = ( Uint32* )x, data[4] ; // receiver

float sizefile ;//Int32 sizefile ; // sizefile of input

(byte)

Uint32 number_block ; // How many blocks have input file got ?

//--------------------------------------------------------------------

-------------//

// Open file input and output

//--------------------------------------------------------------------

-------------//

pfile_in = fopen("D:\\CCS\\workspace\\LowpassFilter\\x.bin","rb");

pfile_out = fopen("D:\\CCS\\workspace\\LowpassFilter\\y.bin","wb");

if ( ( pfile_in == NULL ) || ( pfile_out == NULL ) )

{


19

printf(" Error : can't open files \n");

exit(1) ;

}

//--------------------------------------------------------------------

-------------//

// Buffer Data

//--------------------------------------------------------------------

-------------//

pdata_in = ( Uint8* ) malloc( 4 * Lx * sizeof( Uint8 ) ) ;

pdata_out = ( Uint8* ) malloc( 4 * Lx * sizeof( Uint8 ) );

if ( ( pdata_in == NULL )|| ( pdata_out == NULL ) )

{

printf(" Error : memory are full \n") ;

exit(1);

}

//--------------------------------------------------------------------

-------------//

// xem file x.bin co bao nhieu byte

//--------------------------------------------------------------------

-------------//

fseek( pfile_in, 0L , SEEK_END ) ;

sizefile = (float)ftell ( pfile_in ) ; // sizefile dang byte

fseek( pfile_in, 0L, SEEK_SET ) ;

//--------------------------------------------------------------------------

-------//

// Processing

//--------------------------------------------------------------------

-------------//

for ( i = 0 ; i < M ; i++ )

ytemp[i] = 0 ;

for ( number_block = 0 ; number_block < sizefile /( 4*Lx ) ;

number_block++ )

{

fread( pdata_in, sizeof(Uint8), 4 * Lx, pfile_in ) ;

for ( i = 0 ; i < Lx ; i++ )

{


20

if ( number_block % 50 == 0 ) printf(" %ld \n ", number_block ) ;

//--------------------------------------------------------------

-------------------//

fread( pdata_in, sizeof(Uint8), 4 * Lx, pfile_in ) ;

for ( i = 0 ; i < Lx ; i++ )

{

data[0] = (Uint32)( *( pdata_in + 4*i ) ) ;

data[1] = (Uint32)( *( pdata_in + 4*i + 1 ) ) > 16 ) ;


21

*( pdata_out + 4*i + 3 ) = (Uint8) ( ( tempt & 0xFF000000 ) >> 24 ) ;

}

fwrite( pdata_out, sizeof(Uint8), 4 * Lx, pfile_out) ;

}

//--------------------------------------------------------------------

-------------//

//--------------------------------------------------------------------

-------------//

fread( pdata_in, sizeof(Uint8), (sizefile - number_block * Lx * 4 ) ,

pfile_in ) ;

for ( i = 0 ; i < Lx ; i++ )

{

if ( i < (sizefile/4 - number_block * Lx ) )

{

data[0] = (Uint32)( *( pdata_in + 4*i ) ) ;

data[1] = (Uint32)( *( pdata_in + 4*i + 1 ) )


22

for ( k = 0 ; k < M ; k++ )

{

y[ k ] += ytemp[ k ] ;

ytemp[ k ] = y[ k + Lx ] ;

}

//--------------------------------------------------------------------

-------------//

for (i = 0; i < Lx ; i++ )

{

tempt = *( p_y_Uint32 + i ) ;

*( pdata_out + 4*i ) = (Uint8) ( tempt & 0x000000FF

) ;

*( pdata_out + 4*i + 1 ) = (Uint8) ( ( tempt & 0x0000FF00 ) >>

8 ) ;


16 ) ;

*( pdata_out + 4*i + 3 ) = (Uint8) ( ( tempt & 0xFF000000 ) >>

24 ) ;

}

fwrite( pdata_out, sizeof(Uint8), 4 * Lx, pfile_out) ;

//--------------------------------------------------------------------

-------------//

for (i = 0; i < M ; i++ )

{

tempt = *( ytemp + i ) ;

*( pdata_out + 4*i ) = (Uint8) ( tempt & 0x000000FF

) ;


8 ) ;


16 ) ;

*( pdata_out + 4*i + 3 ) = (Uint8) ( ( tempt & 0xFF000000 ) >>

24 ) ;

}


23

III. Kt qu

Kt qu thc hin c

Nhm tm hiu l thuyt b FIR v mt s l thuyt lin quan trong bi tp ln

ny.

Tm c b lc c p ng ph hp vi yu cu ca project

Thc hin code trong CCS v build thnh cng

M phng MATLAB c kt qu ph hp vi yu cu

fwrite( pdata_out, sizeof(Uint8), 4 * M , pfile_out) ;

//--------------------------------------------------------------------

-------------//

// Close

//--------------------------------------------------------------------

-------------//

free(pdata_in);

free(pdata_out) ;

fclose(pfile_in) ;

fclose(pfile_out) ;


24

IV. Ti liu tham kho

Gio trnh X l s tn hiu v wavelet L Tin Thng.

Gio trnh: Digital Design of Signal Processing Systems - Shoab Ahmed Khan.

Gio trnh: Digital Signal Processing Using MATLAB, 3rd Edition

Vinay K.Ingle v John G.Proakis

Cc ti liu, ebook c thu thp trn mng Internet.

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