thiet ke mach loc so iir su dung matlab

7/23/2019 thiet ke mach loc so iir su dung matlab

1/92

TRNG I HC K THUT CNG NGHIPTHI NGUYN

KHOA IN T

B MN. K THUT IN T

N MN HC

H THNG IN T IN HNH

Sinh vin : 1. Nguyn Th Hin MSSV:DTK1151030237

2. Ng Th Xun MSSV:DTK1151030315

3. Nguyn Hng Qun MSSV:DTK0851030193

Gio vin hng dn : TS. Nguyn Phng Huy

Thi Nguyn2015


2/92

TRNG HKTCN CNG HO X HI CH NGHA VIT NAM

KHOA IN T c lp - T do -Hnh phc

N MN HC

MN HC CC H THNG IN T IN HNH

B MN K THUT IN TSinh vin: 1. NGUYN TH HIN Lp: K47KDT02

2. NG TH XUN Lp: K47KDT02

3.NGUYN HNG QUN Lp:K44KDT

Ngnh : K thut in t

Ngy giao Ngy hon thnh

1.Tn ti: Thit k v thi cng b lc s IIR s dng FPGA

2. Ni dung thuyt minh tnh ton

3. Cc bn v, chng trnh v th

Thng qua phn

Xc nh yu cu

Thng qua phn

thit k

Thng qua phn

xy dng h thng

ng cho bo

v

TRNG B MN

(K v ghi r h tn)

GIO VIN HNG DN

(K v ghi r h tn)


3/92

NHN XT CA GIO VIN HNG DN

...........................................................................................................................................................................................................................

...........................................................................................................................................................................................................................

...........................................................................................................................................................................................................................

...........................................................................................................................................................................................................................

Thi Nguyn, ngy.thng..nm 2015

GIO VIN HNG DN

(K ghi r h tn)


4/92

i

MC LC

MC LC............................................................................................................................. i

DANH MC HNH NH.................................................................................................... v

DANH MC BNG BIU ................................................................................................. iv

DANH MC CC T VIT TT...................................................................................... v

PH LC............................................................................................................................ vi

LI M U...................................................................................................................... 1

1 CHNG 1. TNG QUAN V THIT K LC S................................................ 2

1.1

Tn hiu s v h thng x l tn hiu s ................................................................ 2

1.1.1 Khi nim v tn hiu v h x l tn hiu....................................................... 2

1.1.2

H x l s....................................................................................................... 2

1.1.3 Tn hiu v h x l s trong min phc z....................................................... 3

Php bin i z.......................................................................................... 3

Hm h thng H(z).................................................................................... 4

1.1.4

Tn hiu s v h x l s trong min tn s ................................................ 5

Bin i Fourier......................................................................................... 5

Hm h thng H(ej)................................................................................ 7

1.1.5 Thc hin h thng s...................................................................................... 7

H thng khng quy............................................................................. 7

H thng quy........................................................................................ 8

1.2

Tng quan v b lc s........................................................................................... 9

1.2.1 Khi nim lc s v b lc s.......................................................................... 9

1.2.2

ng dng ca lc s......................................................................................... 9

1.2.3 Phn loi b lc s........................................................................................... 9


5/92

ii

1.2.4

c tuyn tn s ca b lc s l tng.......................................................... 9

B lc thng thp l tng...................................................................... 10

B lc thng cao l tng....................................................................... 10

B lc thng di l tng........................................................................ 11

B lc chn di l tng......................................................................... 12

1.2.5 c tuyn tn s b lc thc t...................................................................... 13

1.2.6

Cc tham s ca b lc thc t....................................................................... 13

1.3 Phng php thit k b lc s c p ng xung chiu di v hn IIR t b lc

tng t s dng cng c matlab................................................................................... 14

1.3.1

Gii thiu Matlab........................................................................................... 14

1.3.2 S dng Filter Design and Analysis Tool (FDATool) .................................. 14

Filter Design and Analysis Tool (FDATool ................................................................... 14

1.3.3 S dng M file vi cc lnh h tr................................................................ 16

1.3.4

Cc b lc tng t........................................................................................ 18

B lc Buterworth................................................................................... 18

B lc Chebyshev.................................................................................... 21

B lc Elliptic.......................................................................................... 25

Cc p ng pha ca blc in hnh ..................................................... 26

1.3.5 Cc phng php chuyn i t b lc tng t sang b lc s................... 27

Phng php bt bin xung.................................................................... 27

Phng php bin i song tuyn........................................................... 29

Phng php tng ng vi phn......................................................... 31

1.3.6

Cc bc tnh ton v tng hp b lc s IIR............................................... 31

V d minh ha........................................................................................ 32

1.3.7

Php bin i bng tn ................................................................................... 39


6/92

iii

1.4

Cu trc ca blc IIR ......................................................................................... 42

1.4.1 Cu trc blc sIIR dang trc tip ............................................................. 42

1.4.2

Cu trc b lc s IIR dng ni tip.............................................................. 44

1.4.3 Cu trc b lc s IIR dng song song.......................................................... 46

1.4.4

Cu trc b lc IIR dng dn (mt co)......................................................... 48

2

CHNG 2. THIT K MCH TCH HP S S DNG CNG NGH FPGA

48

2.1 Tng quan v cng ngh FPGA............................................................................ 48

2.1.1 Gii thiu v FPGA........................................................................................ 48

2.1.2

Kin trc chung ca mt FPGA..................................................................... 49

Khi logic c bn lp trnh c............................................................. 50

H thng mch lin kt............................................................................ 51

Cc phn t thit k sn khc.................................................................. 51

2.2

Ngn ng lp trnh VHDL.................................................................................... 51

2.2.1 Cc u im ca VHDL................................................................................. 52

2.2.2

Cu trc mt m hnh h thng s dng ngn ng VHDL............................ 53

2.3 Cc thao tc lp trnh trn Altium Designed. ........................................................ 53

2.4

NanoBoard NB2DSK01 ........................................................................................ 55

2.4.1 Kin trc tng quan........................................................................................ 55

2.4.2

Thng s k thut NB2DSK01...................................................................... 55

3 CHNG 3. THIT K B LC S S DNG FPGA....................................... 57

3.1

Bi ton thit k.................................................................................................... 57

3.2

Tnh ton thit k.................................................................................................. 58

3.3 Thut ton v chng trnh Matlab....................................................................... 59

3.3.1 Lu thut ton........................................................................................ 60


7/92

iv

3.3.2

Chng trnh matlab...................................................................................... 61

Cc hm s dng trong chng trnh...................................................... 61

Chng trnh............................................................................................ 65

kt qu..................................................................................................... 70

3.3.3

M phng bng Simulink ............................................................................... 74

3.4 Thc hin b lc s dng FPGA........................................................................... 77

4

CHNG 4: NH GI KT LUN..................................................................... 78

4.1 Ch tiu k thut .................................................................................................... 78

4.2

Cht lng b lc thc t...................................................................................... 78

4.3 Kt lun................................................................................................................. 78

5

TI LIU THAM KHO.......................................................................................... 79


8/92

v

DANH MC HNH NH

Hnh 1-1 S m t h x l s trong min thi gian ri rc n......................................... 3

Hnh 1-2 S khi h x l s TTBBNQ theo hm h thng H(z).................................. 5

Hnh 1-3 p ng xung h(n) ca h thng tuyn tnh bt bin........................................... 7

Hnh 1-4 S khi ca h thng khng qui................................................................. 8

Hnh 1-5 S khi ca h thng qui............................................................................ 8

Hnh 1-6 S khi ca b lc s trong min thi gian ri rc......................................... 9

Hnh 1-7 th p ng bin ca b lc s thng thp l tng................................ 10

Hnh 1-8 th p ng bin ca b lc s thng cao l tng................................. 11

Hnh 1-9 th p ng bin ca b lc s thng di l tng.................................. 12

Hnh 1-10 th p ng bin ca b lc s chn di l tng.................................. 12

Hnh 1-11 c tnh bin tn s ca b lc thng thp thc t.................................... 13

Hnh 1-12 Giao din ca FDATool................................................................................... 15

Hnh 1-13 p ng bin c chun ha ca lc Butterworth thng thp.................. 18

Hnh 1-14 Chebyshev loi 1 c bc l (N=5).................................................................... 23

Hnh 1-15 Bnh phng p ng bin ca lc thng thp Chebyshev -2 ..................... 24

Hnh 1-16Hai dng thca p ng bnh phng-bin (N lv N chn) .............. 25

Hnh 1-17 nh x mt phng phc trong php bin i bt bin xung............................ 27

Hnh 1-18nh xmt phng phc trong php bin i song tuyn tnh ......................... 29

Hnh 1-19 Kt qu thu c khi tnh ton bng cng c matlab...................................... 37

Hnh 1-20 Kt qu thu c trn mn hnh comand sau khi chy chng trnh matlab.. 38

Hnh 1-21Cc thng skthut ca cc blc chn tn ................................................ 40


9/92

vi

Hnh 1-22 Cu trc b lc IIR trc tip loi 1 .................................................................. 42

Hnh 1-23 Cu trc trc tip loi II(M=N)........................................................................ 43

Hnh 1-24 Cu trc b lc IIR chuyn v trc tip loi II ................................................. 44

Hnh 1-25 Cu trc ni tip cc h thng bc II v th hin mi mt lc bc II.............. 46

Hnh 1-26 Cu trc song song ca hthng IIR............................................................... 47

Hnh 1-27 Cu trc ca mt mt bc II trong th hin h thng IIR song song............... 47

Hnh 1-28 Cu trc dng trc tip ca h ton cc........................................................... 48

Hnh 2-1 Cu trc tng th ca mt FPGA....................................................................... 50

Hnh 2-2 Khi Logic......................................................................................................... 50

Hnh 2-3 Cc thao tc to project mi trong Altium designed..................................... 53

Hnh 2-4 Cc thao tc add file chng trnh VHDL.................................................... 54

Hnh 2-5 Thao tc bin dch chng trnh ........................................................................ 54

Hnh 2-6 Hnh nh ca NanoBoard NB2DSK01.............................................................. 57

Hnh 3-2 im cc v im khng................................................................................... 71

Hnh 3-3 p ng bin v p ng xung dng tn hiu tng t v s.................... 72

Hnh 3-4 p ng bin v p ng pha ........................................................................ 72

Hnh 3-5 Dng ph ca tn hiu vo ra.............................................................................. 73

Hnh 3-6 Hnh nh m phng b lc bng Simulink........................................................ 74

Hnh 3-7 Tn hiu u vo ................................................................................................. 76

Hnh 3-8 Tn hiu u ra................................................................................................... 77


10/92

iv

DANH MC BNG BIU

Bng 1-1 Cc tnh cht ca php bin i z hai pha.......................................................... 3

Bng 1-2 Cc tnh cht c bn ca bin i Fourier vi tn hiu ri rc............................ 5

Bng 1-3 Bin i tn cho cc b lc................................................................................ 41


11/92

v

DANH MC CC TVIT TT

Cc t vit tt Din gii

TTBBNQ Tuyn tnh bt bin nhn qu

FDATool Filter Design and Analysis Tool

LP Low pass

HP High pass

BP Bandpass

BS Bandstop

IIR Infinite impulse response filter

FPGA Field-programmable gate array

VHSIC Very high speed itergrated circuit

LUT Look-Up Table

CLB Configurable Logic Blocks

CPLD Complex Programmable Logic Device

VHDL Very high speed itergrated circuit Hardware Description Language

IEEE Institude of Electrical and Electronics Engineers

JTAG Join Test Action Group

LED Light emitting diode


12/92

vi

PHLC

Cc hm matlab s dng trong chng

trnh

Din gii

[C,B,A] = dir2cas(b,a) Chuyn i dng trc tip thnh dng ghp

tng

[db,mag,pha,grd,w] = freqz_m(b,a) Tnh bin tng i (dB), bin tuyt

i, pha, nhm tr, di mu tn st hm

h thng H(z) c h s t thc l b, h smu thc l a

[b,a]= bilinear(cs,ds,Fs) Bin i song tuyn chuyn Ha(s) thnh

H(z)

b = cc h s t thc ca H(z)

a = cc h s mu thc ca H(z)

cs = cc h s t thc ca Ha(s)ds = cc h s mu thc ca Ha(s)

Fs = tn s ly mu

[b,a]=u_buttap(N,Omegac) (s dng bn

trong hm afd_butt)

thit k mt b lc Analog Butterworth

cha chun ho vi c ty , bc N

[ha,x,t] = impulse(cs,ds) p ng xung ha(t) ca blc Analog

Hm y = filter(b,a,x) Lc tn hiu x qua h thng H(z) c h s t

thc l b, h s mu thc l a.


13/92

vii

y l tn hiu thu c sau khi lc

[cs,ds]=afd_butt(OmegaP,OmegaS,Rp,As) thit k blc thng thp analog

Butterworth, cho bi cc ch tiu ca n

fft(x,n) Phn tch ph tn hiu vo ra

[bz,az] = zmapping(bZ,aZ,Nz,Dz) Chuyn i bng tn thu c ccblc

chn tn khc tblc thng thp sthit

k c

freqz(b,a) v p ng bin (dB) v p ng pha

()


14/92

1

LI MU

Tn hiu hu nh xut hin tt c cc ngnh khoa hc v k thut , v d nh trong

m hc, sinh hc, thng tin lin lc, h thng iu khin, rada, vt l hc, a cht hc v

kh tng hc. C hai dng tn hiu c bit n. l tn hiu lin tctheo thi gian v

tn hiu ri rc theo thi gian.

Mt tn hiu ri rc, cng nh mt tn hiu lin tc, c th c biu din bi mt

hm ca tn s v c bit n nh l ph tn ca tn hiu. Lc s l mt qu trnh m

ph tn ca tn hiu c thb thay i, bin dng ty thuc vo mt s c tnh mong

mun. N c th dn n s khuch i hoc suy gim trong mt di tn s, b i hoc c

lp mt thnh phn tn s c th, S dng b lc s c rt nhiu tc dng, v d nh:

loi i thnh phn tn hiu khng mong mun nh nhiu, loi b mo xuyn gia cc knhtruyn dn hoc sai lch trong o lng, phn tch hai hoc nhiu tn hiu ring bit

c trn ln theo ch nh nhm cc i ha s s dng knh truyn, phn tch cc tn

hiu trong cc thnh phn tn s ca chng, nn tn hiu, truyn tn hiu ri rc theo

thi gian sang tn hiu lin tc theo thi gian.

B lc s l mt h thng s c th c s dng lc cc tn hiu ri rc theo thi

gian. C nhiu phng php nghin cu, tng hp cng nh thit k b lc s, in hnh

l hai phng php thit k b lc s c p ng xung hu hn (FIR) v phng php thit

k b lc s c p ng xung v hn (IIR).

n ny trnh by phng php thit k b lc s c p ng xung v hn (IIR).

Qu trnh lm v tm hiu gip chng em bit c tng quan v FPGA, u im ca vic

s dng VHDL khi thit k FPGA, nhng vn c bn v VHDL cng nh cc phn tch,

tnh ton da trn nn tng ca ngn ngMatLab

Em xin chn thnh cm n thy gio TS.Nguyn Phng Huy tn tnh gip

chng em hon thnh n ny.

Trong qu trnh thc hin lng kin thc cn rt hn ch v trong thi gian ngn nnchng em cn nhiu thiu st mong thy c v cc bn sinh vin ng gp kin n

ca ca chng em c hon thin hn.

Chng em xin chn thnh cm n!


15/92

2

1 CHNG 1. TNG QUAN VTHIT KLC S

1.1

Tn hiu sv hthng xl tn hiu s

1.1.1

Khi nim vtn hiu vhxl tn hiu Tn hiul biu hin vt l ca thng tin. V mt ton hc tn hiu c coi l hm

ca mt hay nhiu bin c lp.

V d: Tn hiu m thanh l s bin thin ca p sut theo thi gian P(t) hoc cng c th

coi tn hiu m thanh l s bin thin p sut theo khng gian P(x,y,z)

Phn loi tn hiu: Theo dng ca bin thi gian tv gi tr hm s x(t), ngi ta

phn loi tn hiu nh sau:

-

Tn hiu lin tc x(t)l tn hiu c bin thi gian lin tc.- Tn hiu ri rc x(nT)l tn hiu c bin thi gian gin on t = nT.

-

Tn hiu lng tl tn hiu ch nhn cc gi tr xc nh bng s nguyn ln

mt gi tr c s gi l gi tr lng t.

- Tn hiu tng tl tn hiu lin tc c gi tr lin tc hoc lng t.

-

Tn hiu xungl tn hiu c gi tr hm s gin onloi mt. Tn hiu xung

c th l tn hiu lin tc hoc ri rc.

- Tn hiu sl nhm xung c m ho theo gi tr lng t ca tn hiu ti cc

thi im ri rc cch u nhau.Mi xung ca tn hiu s biu th mt bit ca t m, n ch c hai mc in p, mc

in p thp l gi tr logic "0", mc cao l gi tr logic "1".

X l tn hiul thc hin cc tc ng ln tn hiu nh khuch i, suy gim, chn

lc, bin i, khi phc... gi tr v dng ca tn hiu.

H x l tn hiul cc mch in, cc thit b, cc h thng dng x l tn hiu.

1.1.2 Hxl s

Mt h thng x l s tn hiu s xc lp mi quan h gia tn hiu vo v tn hiu ra:y[n] = T(x[n]) m t h x l s trong min thi gian ri rc

x[n] y[n]T(x[n])


16/92

3

Hnh 1-1 S m thxl strong min thi gian ri rc n

1.1.3 Tn hiu vhxl strong min phc z

Php bin i z

Php bin izc s dng cho cc dy s. Bin izthun chuyn cc dy s

nguyn n thnh hm bin s phc z, bin i zngc chuyn thnh cc hm bin s

phcz thnh dy bin s nguyn n. Tn hiu v h thng ri rc s c biu din trong

min phcz. Phng php kho st gin tip trong min zc bit quan trng trong vic

phn tch tn hiu v h thng ri rc v n cho nhng kt qu kh quan, m nu kho st

trc tip trong min bin s c lp t nhin s khng c c.

Bng 1-1 Cctnh cht ca php bin i z hai pha

Hm gc (min n) Hm nh (min z) Min hi t

( )x n ( )X z x xR z R

( )y n ( )Y z y yR z R

. ( ) . ( )a x n b y n . ( ) . ( )a X z b Y z Max ,x yR R z min ,x yR R

( )x n k ( )kz X z x xR z R

( )na x n 1( )X a z x xa R z a R

( )x n 1( )X z 1 1

x x

zR R

. ( )n x n ( )

.dX z

z

dz

x xR z R

( ) ( )x n y n ( ) . ( )X z Y z Max ,x yR R z min ,x yR R


17/92

4

( ) . ( )x n y n 11 ( ). ( ). .

2C

zX Y v v dv

j v

Max ,x yR R z min ,x yR R

( )x n ( )X z x xR z R

( )xyr m 1( ) ( ). ( )xyR z X z Y z

Max ,x yR R z min ,x yR R

Hm hthng H(z)

nh ngha: Hm h thngH(z) ca h x l s TTBBNQ l bin izca c tnh xung

h(n):0

( ) [ ( )] ( ). n

n

H z ZT h n h n z

ViRC[H(z)]: z > Rh-Phn ngy(n) ca h x l s TTBBNQ c tnh theo tch chp:

y(n) =x(n)* h(n)

C th tm c: X(z) =ZT[x(n)]v H(z) =ZT[h(n)]

Do , theo tnh cht tch chp ca bin i z c:

Y(z) =ZT[y(n)]=x(n)* h(n) =X(z).H(z) (1.1.3.1)

T suy ra: ( )( )( )

Y zH zX z

(1.1.3.2)

Theo (1.1.3.2), hm h thngH(z) ca h x l s TTBBNQ l t s ca phn ng

Y(z) v tc ngX(z), do hm h thngH(z) cn c gi l hm truyn tzca h x

l s TTBBNQ.

Biu thc (1.1.3.2) cho php tm hm h thngH(z) ca h x l s TTBBNQ khi bit

tc ngX(z) v phn ng Y(z), cn biu thc (1.1.3.1) cho php tm phn ngy(n) ca h

x l s TTBBNQ khi bit hm h thng H(z) v tc ngX(z).

Ly bin iz ngc hm h thng H(z) ca h x l s TTBBNQ, nhn c c

tnh xung h(z) ca h:

h(n)= IZT[H(z)] ViRC[H(z)]: z > Rh-


18/92

5

T quan h vo ra (1.1.3.1), c th m t h x l s TTBBNQ theo s khi hnh

1.2 do hm h thngH(z) c trng cho cu trc phn cng hoc thut ton phn mm

ca h x l s trong minz.

X(z) y(z)

Hnh 1-2S khi hxl sTTBBNQ theo hm hthng H(z)

1.1.4 Tn hiu svhxl strong min tn s

Cng nh phng php bin i tn hiu s v h x l s sang min phcz, phng

php bin i sang min tn s cng l mt phng php gin tip phn tch tn hiu

v h x l s cho ta gc nhn mi v tn hiu s v h x l s trong min tn s lin tc.Bin i Fourier

Bng 1-2 Cc tnh cht c bn ca bin i Fourier vi tn hiu ri rc

Tnh cht Min bin s n Min tn s lin tc

K hiu ( )x n

1( )x n

2( )x n

( )jX e

1( )jX e

2 ( )jX e

Cp bin i Fourier 1( ) ( )

2

j j nx n X e e d

( ) ( )j j n

n

X e x n e

Tuyn tnh 1 2( )ax n bx n 1 2( ) ( )j jaX e bX e

Tr0( )x n n 0 ( )

j n je X e

i xng ( )x n thc *( ) ( )j jX e X e

Re ( ) Re ( )j jX e X e

H(z)


19/92

6

Im ( ) Im ( )j jX e X e

( ) ( )j jX e X e

arg ( ) arg ( )j jX e X e

Lin hp phc ( )x n ( )jX e

Bin s o ( )x n ( )jX e

Tch chp 1 2( )x n x n 1 2( ). ( )j jX e X e

Tch (i s) 1 2. ( )x n x n ( ') '1 2

1

( ) ( )d '2

j j

X e X e

Vi phn trong min

nx(n) ( )d

jdX ej

Tr tn s 0e ( )j n x n 0( )jX e

iu ch0( )cosx n n 0 0( ) ( )

1 1

2 2

j jX e X e

Quan h Parseval1 2( ) ( )

n

x n x n

2( )

n

x n

1 2

1( ) ( ) d

2

j jX e X e

2

1

1( ) d

2

jX e

Tng quang1 2 1 2

( ) (m) (m )x x

m

r n x x n

1 2( ). ( )j jX e X e

nh l Weiner

Kintchine

( )xxr n 2R ( ) ( ) ( )j j jxx xxe S e X e


20/92

7

Hm hthng H(ej)

Nh bit p ng xung h(n) ca h thng tuyn tnh bt bin chnh l p ng (hay

p ng ra) ca h thng vi kch thch (hay kch thch vo) ( ) ( )x n n , nh minh hanhhnh 1.1.3 di y:

( ) ( )x n n y(n)=h(n)

Hnh 1-3p ng xung h(n) ca hthng tuyn tnh bt bin

Vi u vo kch thch

( ) j nx n e vi n

Th p ng ra ( )y n ca h thng s c tnh:

( )( ) ( ) ( ) ( ) ( )j n m j m j n

m m m

y n h m x n m h m e h m e e

t:

(e ) ( )j j m

m

H h m e

Ta c:

( ) (e ).j j ny n H e

(e )jH c gi l p ng tn s ca h thng.

1.1.5 Thc hin hthng s

Hthng khng quy

L h thng c trng bi phng trnh sai phn tuyn tnh h s hng bc N= 0

H n

1:)()( 00

arnxbnyM

r

r


21/92

8

H thng khng qui cn gi l h thng c p ng xung di hu hn FIR

(Finite Impulse Response )

H thng khng qui lun n nh do :

Hnh 1-4S khi ca hthng khng qui

Hthng quy

L h thng c trng bi phng trnh sai phn tuyn tnh h shng bc N > 0

H thng qui cn gi l h thng c p ng xung di v hn IIR (Infinite

Impulse Response )

H thng qui c th n nh hoc khng n nh

Hnh 1-5 S khi ca hthng qui

)(00

M

r

r

r

brhS

)()(00

rnxbknyaM

r

r

N

k

k


22/92

9

1.2 Tng quan vblc s

1.2.1 Khi nim lc svblc s

B lc s l mt h thng lm bin dng s phn b tn s cc thnh phn ca mt tn

hiu theo cc ch tiu cho trcB lc s l mt HT-TT-BB trong min thi gian ri rc s khi c dng

X(n)

Hnh 1-6S khi ca blc strong min thi gian ri rc

Trong min tn s c c trngbi p ng tn s: H(ejw)

H(ejw) =DTT [h(n)] = Y(ejw)/ X(ejw)

Lc s l cc thao tc lmbin dng s phn b tn s cc thnh phn ca mt tn

hiu theo cc ch tiu cho nh mt h thng s

1.2.2 ng dng ca lc s

B lc s c rt nhiu ng dng nh: loi i thnh phn tn hiu khng mong

mun, loi b mo xuyn gia cc knh truyn dn hoc sai lch trong o lng, phn

tch hai hoc nhiu tn hiu ring bit c trn ln theo ch nh nhm cc i ha ss dng knh truyn, phn tch cc tn hiu trong cc thnh phn tn s ca chng,

nn tn hiu, truyn tn hiu ri rc theo thi gian sang tn hiu lin tc theo thi gian

1.2.3 Phn loi blc s

Da vo p ng tn s, c th chia b lc ra lm cc loi sau:

- B lc s thng thp

- B lc s thng cao

-

B lc s thng di- B lc s chn di

1.2.4c tuyn tn sca blc sl tng

Vic thit k cc b lc s thc t u i t l thuyt cc b lc s l tng. Ta s tin

hnh nghin cu bn b lc s tiu biunh:

H(n) Y(n)=x(n)*h(n)


23/92

10

B lc s thng thp

B lc s thng cao

B lc s thng di

B lc s chn di

Lc y ta hiu l lc tn s chnh, v vy m tt c cc c trng ca lc tn s u

c cho theo p ng bin .

Blc thng thp l tng

nh ngha: B lc thng thp l tng c c tnh bin tn s khi , nh sau:

1 [ , ]( )

0 [ , ] [ , ]

c cj

hp

c c

KhiH e

Khi v

Hnh 1-7thp ng bin ca blc sthng thp l tng

Cc tham s thc ca b lc thng thp l tng :

- Tn s ct : c

- Di thng : [0, c ]

- Di chn : [ c ,]

B lc thng thp l tng cho tn hiu s c ph nm trong di tn c

i qua,

chn khng chi tn hiu s trong di tn c i qua.

Blc thng cao l tng

nh ngha:B lc thng cao l tng c c tnh bin tn s khi , nh sau:


24/92

11

1 [ , ] [ , ]( )

0 [ , ]

c cj

hp

c c

Khi vH e

Khi

Hnh 1-8thp ng bin ca blc sthng cao l tng

Cc tham s thc ca b lc thng cao l tng:

- Tn s ct : c

- Di chn: [0, c ]

- Di thng : [ c ,]

B lc thng cao l tng cho tn hiu s c ph nm trong di tn c i qua,

chn khng cho tn hiu trong di tn c

i qua.

Blc thng di l tng

nh ngha:B lc di thng l tng c c tnh bin tn s khi , nh sau:

2 1

1 2

1( )

0

c c

j

c c

cn la

H e

i


25/92

12

Hnh 1-9thp ng bin ca blc sthng di l tng.

Cc tham s ca b lc di thng l tng:

- Tn s ct : 1, 2c c

- Di thng : [ 1, 2c c ]

- Di chn : f [0, 1c ] v [ 2c ,]

B lc di thng l tng cho tn hiu s c ph nm trong di tn s 1 2c c

i qua,chn khng cho tn hiu ngoi di tn i qua.

Blc chn di l tng

nh ngha:B lc di chn l tng c c tnh bin tn s khi , nh sau:

2

1 2

2

( )

1

0

c

c cj

c

H

c

e

n lai

Hnh 1-10thp ng bin ca blc schn di l tng.


26/92

13

1.2.5c tuyn tn sblc thc t

Tt c b lc s l tng c c tnh bin tn s dng ch nht, nn c tnh xung

ca chng u l dy khng nhn qu c di v hn, v th khng th thc hin c

cc b lc l tng .

c tnh bin tn s ca b lc s thc t thng c nhp nh trong di thng

v di chn , vi haibin l sn dc nh hnh 1.11

Hnh 1-11 c tnh bin tn sca blc thng thp thc t

1.2.6 Cc tham sca blc thc t

c trng cho b lc thc t, ngi ta s dng cc tham s sau :

1. Loi b lc : Thng thp, thng cao, di thng, di chn

2. Tn s gii hn gii thng c (hayfc).

3. Tn s gii hn di chn p (hayfp).

4. rng di qu cpp (hay pf )

5. nhp nh trong di thng 1 . Trong di thng, c tnh bin tn s

)( jbp eH phi tha mn iu kin 11 )( j

bp eH 11

6. nhp nh trong di chn 2 . Trong di chn c tnh bin tn s )( jbp eH

phi tho mn iu kin : )( jbp eH 2

B lc thc t c p , 1 v 2 cng nh th c tuyn bin tn s cng gn ging

dng ch nht , nn chn lc tn hiu cng t t.


27/92

14

1.3 Phng php thit kblc sc p ng xung chiu di v hn IIR tblc

tng tsdng cng cmatlab

1.3.1 Gii thiu Matlab

Matlab l t vit tt ca Matrix Laboratory Matlab l mt ngn ng lp trnh cp caodng thng dch, n l mi trng tnh ton s c thit k bi cng ty MathWorks. Matlab

cho php thc hin cc php tnh ton s, ma trn, v th hm s hay biu din thng tin

(di dng 2D hay 3D), thc hin cc thut ton v giao tip vi cc chng trnh ca cc

ngn ng khc mt cch d dng.

1.3.2 Sdng Fil ter Design and Analysis Tool (FDATool)

Filter Design and Analysis Tool (FDATool) l mt giao din ha ngi dng (GUI)

trong hp cng c x l tn hiu cho vic thit k v phn tch cc b lc.

Cng c thit k b lc (FDATool) cung cp cho ta nhngk thut tin tin thit

k, phn tch , m phng cc b lc . Vi nhng k thut tin tin trong kin trc v thit

k b lc, N cho php nng cao kh nng x l h thng s trong thi gian thc nh vi

b lc thch nghi,b lc a nhim v s chuyni gia chng.

FDAtool h tr thit k b lc IIR nh sau:

-

Thit k b lc thng ton gii vi c quyn truyn nhm, cho php bn lm cn

bng gia cc nhm truyn, kt qu thu c p tuyn tuyn tnh pha trn ton

gii.

- Thit k b lc IIR vi khun mu nh cho php thit k ti u cc b lc IIR

thng thp thng cao thng gii v chn gii.

- Thit k cng bc b lc IIR khun mu nh,cho php t trc bn knh ln

nht ca cc im cc dn n ci thin mnh m hiu ng lng t ca b lc.

Ngoi ra cn s dng giao din ca FDATool: DATool cho ta mt giao din thit k

b lc s rt mnh v thun tin cho ngi s dng, mt ci rt hay ca n l ta c th

chuyn i t thit k b lc trn giao din thnh ngn ng lp trnh t ta c th nggi v s dng n trong nhng thit k pht trin cao hn.C th ni rng: Thit k b lc

trn giao din ca FDATool v mt chc nng th gn nh ging vi thit k b lc bng

ngn ng lp trnh tr mt s hm chc nng c bit m FDATool khng th c c,b


28/92

15

vo l s rt trc quan v d hiu. Sau y ta bt u khi ng cho FDATool: T ca

s lnh ca windows ta g: FDATool v Eter

Mt giao din c hin ra nh sau:

Hnh 1-12 Giao din ca FDATool

Trn thanh tiu ta c:

- File: cng c cho tp tin

- Edit: cng c son tho

-

Analysis: cng c phn tch

-

View : cng c hin th- Window: Tng thch vi h iu hnh Windows

-

Help: cng c tr gip trong khung: Current filter information (thng tin v b lc)

-

Store Filter: lu b lc vo kho

- Filter manager: Qun l cc b lc c lu gi. Trong khung


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16

- Filter specifications (thuyt minh v b lc)

Trong khung Response type (kiu p ng) bao gm cc p ng:

- lowpass (b lc thng thp ).

-

Highpass (blc thng cao)- Bandpass ( b lc thng gii )

- Bandstop ( b lc chn gii )

- Differentiator (b vi phn)

1.3.3 Sdng M f ile vi cc lnh htr

Trong MATLAB, M-file l cc file chng trnh c son tho v lu dng vn

bn. C hai loi M-file l Script file (file lnh) v Function file (file hm). C hai u c

phn tn m rng l ".m ". MATLAB c rt nhiu M-file chun c xy dng sn. Ngi

dng cng c th to cc M file mi tu theo nhu cu s dng.

Lp trnh dng SCRIPT FILE

Thay v nhp v thc thitng cu lnh ti ca s Command window, ta c th son

v lu tt c cc cu lnh cn thit gii bi ton vo mt Script file. Sau ch cn g

tn file thc thi ton b chng trnh.

M ca s Editor:

-

Cch 1: Trong command window g lnh edit- Cch 2: Vo menu File >New >M-File

-

Cch 3: Nhp chut vo icon

Lu: Vo menu File > Save > t tn tp tin > nhp nt save.

Tp tin Scrift file c phn m rng l ".m", v c lu vo th mc hin hnh. Nu

khng c s la chn khc th th mc hin hnh c mc nh l th mc work ca

MATLAB. Tn tp tin phi bt du bng k t ch, khng c khong trng gia cc k t

(ging nh quy nh v tn bin). Gi thc hin SCRIPT FILE:

-

Cch 1: Trong ca s son tho nhp chut vo nt run trn thanh toolb ar.

-

Cch 2: Tr v mn hnh Command window v g tn file (khng c phn m

rng .m), sau nhn Enter thc thi.


30/92

17

Lu l d gi thc hin theo cch 1 hay cch 2 th MATLAB cng u

M mt M-file ang c xem li hay chnh sa:

- Cch 1: Trong ca sEditor hoc Command window, vo menu File >open

-

Cch 2: Vo ca s Workspace, nhp p chut vo tn M-file cn m.

- Cch 3: Ti Command window, g lnh edit ('ng dn \tn file')

Lp trnh dng FUNCTION FILE

M ca s Editor:

- Cch 1: Trong ca s son tho nhp chut vo nt run trn thanh toolbar.

-

Cch 2: Tr v mn hnh Command window v g tn file (khng c phn m

rng .m), sau nhn Enter thc thi.

Lu l d gi thc hin theo cch 1 hay cch 2 th MATLAB cng u xut kt qutnh ton ti ca s Command Window.

Son tho:

Cu trc chun ca mt hm:

function [danh sch tham s ra] = tn hm (danh sch tham s vo)

Cch lu: Nh cch lu ca Scrift file. Khi lu hm, MATLAb s ly tn hm lm

tn file, ngi lp trnh khng nn sa li tn ny trnh ln ln khi gi thc hin hm.

Mt M-file c th cha nhiu hm. Hm chnh (main function) trong M-file ny phi

c t tn trng vi tn ca M-file. Cc hm khc c khai bo thng qua cu lnh

function c vit sau hm u tin. Cc hm con (local function) ch c s dng bi

hm chnh, tc l ngoi hm chnh ra th khng c hm no khc c th gi c chng.

Tnh nng ny cung cp mt gii php hu hiu gii quyt tng phn ca hm chnh mt

cch ring r, tothun li cho vic lp mt file hm duy nht gii bi ton phc tp.

Tng t vi b lc sFIR, tng hp b lc sIIRch xt n qu trnh xc nh cch s b lc sao cho tha mn cc ch tiu k thut trong min tn s: 1 2, , ,p s .

Ni dung cc phng php tng hp b lc s IIRtrn c s lc tng t, tc l

tng hp b lc tng t trc, sau dng cc phng php chuyn i tng ng mt

cch gn ng t b lc tng t sang b lc s.


31/92

18

1.3.4 Cc blc tng t

Blc Buterwor th

Lc Butterworth l lc tng t ph bin nht. N c bng phng ln nht ti tn

s ( = 0) v tng u trong di thng v di chn. N khng c gn sng, bngthng chuyn tip (gia di thng v di chn) th ngn v p ng pha khng tuyn

tnh (Chebyshev v elliptic cng c p ng pha khng tuyn tnh). Hnh 1.1 ch p

ng bin tn s c chun ha ca lc Butterworth. Bc b lc cao hn gn vi

p ng l tng

Hnh 1-13p ng bin c chun ha ca lc Butterworth thng thp

Biu thc tng qut ca hm truyn vi bc N ca lc lc Butterworth l :

1 21

1 1( )

( )( )...( )( )a N

a a aN aii

H ss p s p s ps p

Hm c N im cc v khng c im khng. Vi mt lc thng thp c hai i slc thit k l bc N v tn s ct (hoc -3 dB) c. Bnh phng bin hm truyn l

2

2

1H ( )

1 ( / )a N

c

ss j

Bnh phng ca p ng bin tn s c c bng cch thay s bng j:


32/92

19

2

2

1| H (j ) |

1 ( / )a N

c

Lc Butterworth c phng ln nht v p ng bin ca n bng khng ti tn

s =0. V lc Butterworth khng c gn sng, i s p v sc xem l s suy

gim. Nhng im cc ca p ng bnh phng hm truyn c cho bi

2

1/21 0 ( 1)

N

N

c

c

ss j

j

Ta din t -1 v j nh thnh phn phc:

2 11 j ie

/2jj e

V vy nhng cc l: (2 j N 1) / 2Njp eai

, i=1,2,3,2N

ln ca tt c cc cc l cv gc pha l: (2 1)

2ai

i N

N

Kt qu ny ch rng cc cphn b u trn mt ng trn c tm ti gc v

bn

knh l tn s ct ctrong mt phng s

Hm thi hnh trn matlab

Hm [z,p,k] = buttap(N)

- thit kmt blc Analog Butterworth chun ho (c= 1) bc N.

- z: zeros; p: poles; k: gain value.

Hm [b,a] = u_buttap(N,Omegac)

- thit kmt blc Analog Butterworth cha chun ho vi C ty ,

bc N.

- Cung cp mt cu trc dng trc tip vi: b l tthc, a l mu thc.

Hm [C,B,A] = sdir2cas(b,a)

-

Chuyn i dng trc tip thnh dng ghp tng.

Ccphng trnh thit k:


33/92

20

B lc thng thp c trng bi cc thng s p,Rp,s v As. V vy u im ca

thit k trong trng hp b lc Butterwoth l thu c bc N v tn s ct c.

Chng ta mong mun:

Ti =p: 21010 log |H ( ) |a pj R hay 10 2

110log

1

pN

p

c

R

Ti =s: 21010 log | H ( ) |a sj A hay 10 21

10log

1

sN

s

c

A

Gii 2 phng trnh trn ta thu c:

Bc N

/10 /10

10

10

10log (10 1) / 10 12log /

p sR A

p s

N

Tn s ct c

-

p ng thng s k thut ti p:

/102

10 1s

p

cAN

- p ng thng s k thut ti s:


34/92

21

/102 10 1ss

cAN

Thi hnh trn matlab:

Hm [b,a] = afd_butt(Wp,Ws,Rp,As)thit kblc thng thp analog Butterworth, cho bi cc chtiu ca n.

Hm [db,mag,pha,w] = freqs_m(b,a,wmax)

p ng bin tuyt i cng nh tng i theo thang dB v p ng pha.

Hm [ha,x,t] = impulse(b,a)

p ng xung Ha(t) ca blc Analog.

Blc Chebyshev

p ng bin ca lc Chebyshev (cng gi l lc Cauer) c mt chuyn tip

hpso vi Butterworth c cng bc lc, v n gn sng ( gn sng ging nhau t nh

ny sang nh khc) trong cng di thng hoc di chn (Chebyshev loi 2).Vi gn

sng zero, lc Chebyshev tr thnh lc Butterworth

Chebyshev-1

Bnhphng ca hm truyn v p ng bin tn s ca Chebyshev-1 bc N l:

2

*2

1| (s) |

1 / /a

N c N c

HC s j C s j

2

2 2

1| H (j ) |

1 /a

N cC

Vi (X),X /N cC l a thc Chebyshev-1 ca loi u tin ca bc N, c l

tns ct thuc i s gn sng. Hm truyn ca lc Chebyshev bc N cng c Ncc,nhng khng nm trn ng trn mt phng s nh trong trng hp ca Butterworth

nhng nm trn ellipse. Biu thc ca a thc Chebyshev-1 c bc khng v cao hn l:

0 1C X

1C X X


35/92

22

22 2 1C X X

33 4 3C X X X

4 24 8 8 1C X X X

5 35 16 20 5C X X X X

.

.

. 1 22N N N XC X XC X C

Hnh1.13 v p ng bin bnh phng chun ha ca lc Chebyshev-1 ca bc

l.

Nh ta thy, n gn sng trong di thng v u trong di chn. Ti tn s bng 0,

bin chun ha l 1.Vi lc Chebyshev-1 c bc chn gi tr ny l

21/ 1 . S

gn sng bng nhau vi bc. gn sng xut hin gia mc cao 1 v mc thp 21/ 1

. Khong cch gia hai mc l bnh phng di thng gn sng nh n 2(1 )p .

T trn ta c ti cnh di thng p ng:

2

2 2

11

1 / p

N pC

V ti cnh di chn p ng l:

2

2 2

1

1 / s

N p cC

Chebyshev loi 1 c bc l (trong trng hp ny N = 5). Vi bc chn, p ng bt

u ti mc thp 21/ 1 nhng sau mt vi dao ng, s t n mc cao 1 trc khi

ri nhanh

2

11

1 p


36/92

23

Hnh 1-14 Chebyshev loi 1 c bc l(N=5)

Hm truyn ca lc Chebyshev-1 ch c cc nm bn tri ca mt ellipse c tm ti

gc, trc chnh dc theo trc o j, v trc o dc theo trc thc . Kch thc ca

ellipse ph thuc i s gn sng. gn sng cng nh chuyn tip cng rng.

-

Thi hnh trn Matlab:

Hm [z,p,k] = cheb1ap(N,Rp)

-

thit kmt b lc analog chun ho Chebyshev-I analog c bc N v gn sng di

thng Rp.

-

z mng cc im khng- p mng cc im cc trong p

-

Gi trli k

Hm [b,a] = u_chb1ap(N,Rp,Omegac): Trli Ha(s) theo dng trc tip.

- Cc phng php thit k:

- Cho p, s, Rp v As, ba tham sc yu cu xc nh mt blc Chebyshev-I

-

Ta c:

0.1

10 1pR

/2010 s

AA


37/92

24

2

2

1Ag

210

2

10

10log 1

10log 1r r

g gN

Thi hnh trn Matlab dng hm [b,a] = afd_chb1(Wp,Ws,Rp,As)

Chebyshev-2

Lc Chebyshev loi 2 (Chebyshev-2) hm truyn c c cc v khng. p ng bin

bt u ti 1 v gim u trong di thng, v gn sng trong di chn. Bnh phngpng bin c cho bi biu thc:

2 2

2

2 2

/| |

1 /

N c

a

N s

CH j

C

vi

21

s

s

Hnh 1-15Bnh phng p ng bin ca lc thng thp Chebyshev-2

- Thi hnh trn Matlab:

Function [z,p,k] = cheb2ap(N,As);

Normalized Chebyshev-II


38/92

25

Function [b,a] = u_chb2ap(N,As,Omegac)

Unnormalized Chebyshev-II

Function [b,a] = afd_chb2(Wp,Ws,Rp,As)

Blc El li ptic

Lc Chebyshev c mt chuyn tip ngn hn lc Butterworth v n cho php

gn sng trong c di thng v di chn v v vy c chuyn tip nh nht gia cc

lai lc c cng bc lc. Biu thc ca hm truyn v p ng tn s ca lc elliptic

th ging vi lc Chebyshev

2

2 2

1| |

1 /a

N p

H jU

Vi :

-

N : bc

- : gn sng di thng

- UN : l hm Jacobian elliptic bc-N

Hnh 1-16Hai dng thca p ng bnh phng-bin (N lv N chn)

Tnh ton cho b lc bc N:

2

1

2

1

1

1

K K KN

K K K K

Vi :


39/92

26

p

s

K

12 1

KA

/2

2 20(x)

1 sin

dK

x

- Thi hnh trn Matlab:

Hm [z,p,k]=ellipap(N,Rp,As);Normalized elliptic analog prototype

Hm [b,a] = u_ellipap(N,Rp,As,Omegac)Unnormalized elliptic analog prototype

Hm[b,a] = afd_elip(Wp,Ws,Rp,As)

Analog Lowpass Filter Design: EllipticThit k ca lc elliptic th phc tp hn lc Chebyshev

Cc p ng pha ca blc in hnh

-

Blc Elliptic cho tnh nng ti u vp ng bnh phng-bin nhng c p

ng pha phi tuyn hn trong di thng (khng thch hp cho nhiu ng dng).

-

Ngay ckhi chng ta quyt nh khng lo lng g n p ng pha trong thit k,

pha vn givai tr quan trng trn ton hthng.-

i vi cc blc Buttworth , c p ng bin bng phng ti a v i hi bc

N cao hn (nhiu im cc hn) t c cng mt chtiu di chn. Tuy nhin

chng c mt p ng pha khng tuyn tnh trong di thng.

- Cc blc Chebyshev c cc c tnh pha nm gia.

- V vy trong cc ng dng thc tchng ta xem xt cc blc Butterworth cng

nh Chebyshev, cng thm cc blc elliptic.

-

Vic la chn phthuc vo cbc ca blc (thng nh hng n tc x

l

v phc tp thi hnh) v cc c tnh pha (iu khin mo).


40/92

27

1.3.5 Cc phng php chuyn i tblc tng tsang blc s

Cc phng php chnh chuyn t blc tng t sang s:

- Phng php bt bin xung.

-

Phng php bin i song tuyn.- Phng php tng ng vi phn.

Phng php bt bin xung

Ni dung ca phng php l xc nh p ng xung h(n) ca b lc s bng cch ly

mu p ng xung ca b lc tng t ha(t):

( ) ( )s a t nTsh nT h t

Gi thit hm truyn tHa(s) ca b lc tng t c dng:

1

( )N

ia

i ci

kH s

s s

Hm truyn tH(z) ca b lc s c chuyn tng ng theo phng php bt

bin xung s l:

11

(z)1 ci s

Ni

s Ti

kH

e z

Hnh 1-17 nh xmt phng phc trong php bin i bt bin xung

-

Cc tnh cht:

= Re(s):

< 0, nh xvo |z| < 1 (bn trong ng trn n v)

= 0, nh xvo |z| = 1 (trn ng trn n v)

> 0, nh xvo |z| > 1 (bn ngoi ng trn n v)


41/92

28

nh xnhiu s ln mt z : nh xmany-to-one

Mi di bn-v hn bn tri (nm bn mt phng tri) nh xvo bn trong

ng trn n v

Tnh nhn quv n nh l khng thay i;

Aliasing (sai sly mu) xut hin nu blc khng c bng tn-hu hn

-

Thtc thit k:

Vi cc chtiu cho wp, ws, Rp, As, chng ta mun xc nh H(z) bng cch thit

k

trc tin mt blc analog tng ng v sau nh xchng thnh blc smong

mun. Cc bc nh sau:

1. Chn T v xc nh cc tn sanalog: pp

T

, ss

T

2. Thit kmt blc analog Ha(s) sdng cc c tnh ca mt trong ba blcin

hnh trong phn trc.

3. Sdng php khai trin ring phn, khai trin Ha(s) thnh: 1

( )N

ia

i ci

kH s

s s

4. Bin i cc im cc analog thnh cc im cc s thu c blc

s:

11

(z)1 ci s

Ni

s Ti

kHe z

- Thi hnh Matlab:

Hm [b,a] = imp_invr(c,d,T) b = cc hstthc ca H(Z)

a = cc hsmu thc ca H(Z)

c = cc hstthc ca Ha(S)

d = cc hsmu thc ca Ha(S) T = chu kly mu

- Cc thun li v bt li ca nh xbt bin xung :

- y l mt thit kn nh v cc tn s v c quan htuyn tnh.

- Bt tin: Gp phi aliasing (sai sly mu) p ng tn sanalog, v i khi


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aliasing ny l ko chp nhn c.

-Nh vy, phng php thit kny chtin sdng khi blc analog cbng

tn-hu hn bin i thnh blc thng thp hoc thng di khng c dao ng

trong di chn.

Phng php bin i song tuyn

Ni dung ca phng php l php nh x mt phngsca b lc tng t sang mt

phngzca b lc s.

Hm truyn t ca b lc s H(z) c th nhn c t hm truyn t b lc tng

tHa(s), nu ta thay:

1

1

2(1 )

(1 )s

zs T z

Hay quan h gia cc hm truyn tHa(s) vH(z) l:

1

1

2(1 )

(1 )

( ) (s)s

za sT z

H z H

Hnh 1-18nh xmt phng phc trong php bin i song tuyn tnh

- Cc nhn xt:

< 0, nh xvo |z| < 1 (bn trong ng trn n v)

= 0, nh xvo |z| = 1 (trn ng trn n v)

> 0, nh xvo |z| > 1 (bn ngoi ng trn n v)

- Ton bmt phng-na tri nh xvo bn trong vng trn n v. y l php

bin i n nh.


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- Trc o nh xln ng trn n vl nh x1-1. Do khng c aliasing trong

min tn s.

- Quan hca theo lphi tuyn: 1 2

2 tan tan

2 2

T

T

- Thtc thit k:

Vi cc chtiu cho ca blc swp, ws, Rp, As, chng ta cn xc nh H(z). Cc

bc nh sau:

1. Chn mt gi trT tu, v c tht T = 1.

2. Chuyn i cc tn sct p v s, ngha l tnh ton p v s sdng:

2

tan 2

p

pT

2

tan 2ss

T

3. Thit kmt blc thng thp Ha(s) ph hp cc chtiu ny.

4. Cui cng ly:1

1

2 1(z)

1a

zH H

T z

V nhn c H(z) l mt hm hu t

theo z-1

- Thi hnh Matlab:

Hm [b,a] = bilinear(c,d,Fs)

b = cc hstthc ca H(Z)

a = cc hsmu thc ca H(Z)

c = cc hstthc ca Ha(S)

d = cc hsmu thc ca Ha(S)

Fs = tn sly mu

Cc thun li ca bin i song tuyn tnh:

-

L mt thit kn nh.- Khng baliasing (sai sly mu).

-

Khng rng buc vkiu blc c thbin i c.


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Phng php tng ng vi phn

Hm truyn t ca b lc s H(z) c th nhn c t hm truyn t b lc tng

tHa(s), nu ta thay:1

1 sz

sT

Hay quan h gia cc hm truyn tHa(s) vH(z) l:

11( ) ( )s

za sT

H z H s

- Sau khi kho st cc tip cn khc nhau thit kcc blc tng t, chng ta

sn sng bin i chng thnh blc s.

- Cc php bin i ny t c bng cch bo ton cc aspects khc nhau ca cc

blc tng tv lc s.

Bin i bt bin xung

Bo ton hnh dang ca p ng xung tlc tng tthnh lc s

Kthut xp xsai phn hu hn

Chuyn i biu din mt phng trnh vi phn thnh mt phng trnh

sai phn tng ng

Bt bin bc nhy

Bo ton hnh dng ca p ng bc nhy

Bt bin tuyn tnh

Bo ton biu din hm hthng tmin tng tsang min s

Trong phn ny chcp n bin i bt bin xung v bin i song tuyn

tnh

1.3.6 Cc bc tnh ton vtng hp blc sI I R

Bc 1: Xc nh ccch tiu ca b lc s :- Tn s di thng : fp

- tn s di chn :fs

- gn sng di thng : 1

- gn sng di chn : 2


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32

Bc 2: chn phng php chuyn i t b lc tng t sang tng s:

- Bt bin xung

- Bin i song tuyn

- tng ng vi phn

=> chnphng php binisong tuyn

Bc 3:thit k b lc tng t theo cc phng php:

- butterworth

- chebyshev 1

-chebyshev 2

- eliptique

-bessel

=> chnphng php chebyshev 2

Bc 4: Chuyn H(s) sang H(z) v H(jw)

Bc 5: T hm truyn a ra s cu trc ca b lc sau a vo FPGA

V dminh ha

bi: thit k mch lc sIIR t b lc tng t Chebyshevvi cc thng s:

-

Tn s di thng : fp=40hz- Tn s di chn : fs=50hz

- gn di thng : 1=0.3

- gn sng di chn: 2=0.34

Chng trnhtnh ton trn cng c matlab:

clear all;clc

%% Chi tieu bo loc can thiet ke

Fs=1000; % tan so lay mau

As=40; % tan so gioi han dai thong

Rp=50; % tan so gioi han dai chan

xmp=0.3; % gon song dai thong


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xms=0.34; % gon song dai chan

%%

Ts=1/Fs; % chu ky lay mau

Ap=abs(20*log10(1-xmp)); % gon song dai thong (dB)

As=abs(20*log10(xms)); % gon song dai chan (dB)

wp=fp/(Fs/2); % fp chuan hoa theo 1

ws=fs/(Fs/2); % fs chuan hoa theo 1

wpr=fp*pi/(Fs/2); % fp chuan hoa thep pi

wsr=fs*pi/(Fs/2); % fs chuan hoa theo pi

w=0:pi/1023:pi; % vecto tan so

%% Chon kieu bo loc

filter_type = 'butter'; % butter, cheby1, cheby2

switchfilter_type

case'butter'

[n,wc] = buttord(wp,ws,Ap,As); % xc inh bac cua bo loc

[b1,a1] = butter(n,wc); % xc inh he so cua pt Hz b: tu a: mau

case'cheby1'

[n,wc] = cheb1ord(wp,ws,Ap,As);

[b1,a1] = cheby1(n,Ap,wc);

case'cheby2'

[n,wc] = cheb2ord(wp,ws,Ap,As);

[b1,a1] = cheby2(n,As,wc);

end

%%

Hejw=freqz(b1,a1,w); % xc inh ap ung tan so Hejw


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cswprarr=1;

whilew(cswprarr+1)


48/92

35

plot([0 fp],[1-xmp 1-xmp],'r--') % ve duong bao

plot([fp fp],[0 1-xmp],'r--')

plot([fs fs],[xms 1+xmp],'r--')

plot([fs Fs/2],[xms xms],'r--')

% Ve dap ung pha

subplot(222);hold on;grid on

plot(w/pi*Fs/2,unwrap(angle(Hejw))) % xac dinh dap ung pha, angle:goc pha

title('Dap ung pha')

xlabel('Tan so (Hz)');ylabel('Goc pha')

% Ve dap ung bien do (dB)


plot(w/pi*Fs/2,20*log10(abs(Hejw))) %ve duong

title('Dap ung bien do')

xlabel('Tan so (Hz)');ylabel('H(ejw) (dB)')

Log10AxisBottom=-As-50;

axis([0 Fs/2 Log10AxisBottom 1])

% Ve dap ung xung

[h,t]=impz(b1,a1,25); % tinh ra dap ung xung 25: do dai xung can ve


stem(t,real(h)) % ve xung(diem)

title('Dap ung xung h(n)')

xlabel('n');ylabel('h(n)')

%%

figure(2) %tao cua so moi de ve do thi

% Bieu dien diem khong va diem cuc


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subplot(211);zplane(b1,a1)

title('Diem khong va diem cuc');

% Tre nhom va tre pha (thoi gian truyen nhom)

gd = grpdelay(b1,a1,length(w));

gd(1) = []; % Avoid NaNs

TempH1 = Hejw; Tempw = w;

Tempw(1) = []; % Avoid 'Divide by zero'

TempH1(1) = []; % To be the same size as Tempw

pd = -unwrap(angle(TempH1))./Tempw;

subplot(212);plot(Tempw,gd,Tempw,pd,':')

xlabel('Tan so (rad/sec)');

ylabel('Delay (Samples)');

legend('Tre nhom','Tre pha');

title('Tre nhom va tre pha');

axis ([0 pi -1 20]);

Kt qu thu csau khi chy chng trnh trn:


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Hnh 1-19Kt quthu c khi tnh ton bng cng cmatlab


51/92

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Hnh 1-20 Kt quthu c trn mn hnh comand sau khi chy chng trnh matlab

-3 -2 -1 0 1 2 3

-1

-0.5

0

0.5

1

Real Part

Imagin

aryPart

Diem khong va diem cuc

0 0.5 1 1.5 2 2.5 3

0

5

10

15

20

Tan so (rad/sec)

Delay

(Samples)

Tre nhom va tre pha

Tre nhom

Tre pha

0 50 1000

0.5

1

1.5Dap ung bien do

Tan so (Hz)

H(ejw)

0 50 100-3

-2

-1

0

1Dap ung pha

Tan so (Hz)

Gocpha

0 50 100

-40

-20

0

Dap ung bien do

Tan so (Hz)

H(ejw)(dB)

0 10 20 30-0.2

0

0.2

0.4

0.6Dap ung xung h(n)

n

h(n)


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1.3.7 Php bin i bng tn

Mc ch ca phng php ny l thit kcc blc chn tn khc nhau:

- Cc blc thng cao

-

Cc blc thng di- Cc blc chn di

Bng cch sdng cc kt quca lc thng thp v php bin i bng tn.

-

Php bin i bng tn :

Gi HLP(Z) l blc sprototype lowpass cho, v gi H(z) l blc schn tn

c mong mun. Xc nh mt nh xtheo cng thc:

1 1

( )z G z

such that 1 1|LP z G zH z H Z

GisHLP(Z) l mt blc n nh v nhn qu, ta mun rng H(z) cng n nh v

nhn qu. iu ny dn n cc yu cu sau:

1.

G(.) phi l mt hm hu ttheo 1sao cho H(z) l thi hnh c.

2. ng trn n vca mt phng-Z phi nh xln ng trn n vca mt

phng-z.

3.

cho cc blc n nh, bn trong ng trn n vca mt phng-Z cng phinh xln bn trong ng trn n vca mt phng-z.


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Hnh 1-21Cc thng skthut ca cc blc chn tn

t v l bin tn sca Z v z, Z =

v z=

trn ng trn n vtngng ca chng. p ng 2 yu cu u tin, tc l:

1| Z | | G(e ) | 1j v (e )e | G(e ) | jj j Ge

Cng thc tng qut ca hm G(.) thomn cc yu cu trn l mt hm hu tca

kiu ton-thng (all-pass type) c cho bi:

11 1

1'

1

Z ( )

1

nk

k k

zG z

z

vi | | 1k (p ng yu cu 3)

Bng cch chn mt xp xbc n v cc hschng ta c ththu c cc nh

xkhc nhau. Cng thc c sdng rng ri nht cho cc php bin i ny c cho

trong bng sau:


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41

Bng 1-3 Bin i tn cho cc blc

- c kt li cc bc thit kblc sc hn tn

1.

Cc chtiu blc s-chn tn (LP, HP, BP, BS).

2. Chtiu blc sthng thp tnh tcc chtiu trn.

3. Chtiu blc Analog prototype.

4.

Tnh ton v thit kblc thng thp Analog prototype (4 kiu).

5. Dng cc php bin i chuyn thnh blc thng thp s.

6. Bin i bng tn blc sLP thnh blc s-chn tn mong mun


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1.4 Cu trc ca blc IIR

Cng ging nh hFIR hIIR cng c mt sloi cu trc khc nhau nh: dng trc

tip, dng ni tip, cu trc dn v cu trc dn thang ngoi ra cn them cu trc song

song,by gita xt ln lt tng lo cu trc.

1.4.1 Cu trc blc sI IR dang trc tip

Hm truyn t hu tc trng cho blc IIR:

0

1

H(z)

1

Mr

r

r

Nk

k

k

b z

a z

C thxem nh gm 2 hni tip, ngha l:

1 2(z)H ( )H z H Z

y1

H (z) cha cc im khng v 2H ( )Z cha cc im cc tc l:

0

1(z)M

r

r

r

b zH

v1

2H ( 1)N

k

k

k

a zZ

Hnh 1-22 Cu trc blc IIR trc tip loi 1

Cu trc ny i hi M+N+1 nh.


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Hnh 1-23 Cu trc trc tip loi II(M=N)

Nu blc ton cc H2(z) t trc blc ton khng H1(z), sc cu trc ti uhn gi l cu trc trc tip loi II nh trong hnh 1-23 cu trc ny i hi M+N+1 php

nhn, M+N php cng v cc i ca M,N nh, v cu trc trc tip loi II ti thiu ha

c nhnn n c xem l chnh tc

nh l chuyn vpht biu rng:

-

Thay thnt cng bng nt nhnh v ngc li

- o hng ca tt ccc hstruyn t nhnh v cc nhnh

- i chtn hiu vo v tn hiu ra cho nhau

Th hm truyn t sginguyn khng i. Cu trc thu c c tn l cu trc

chuyn vhay dng chuyn v

Ta hy p dng nh l chuyn vi vi cu trc trc tip loi II. Trc ht, ta o

hng tt ccc lung tn hiu trong hnh 1-23, tip n ta i cc nt thnh bcng v


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cc bcng thnh cc nt. Cui cng ta i u vo, u ra cho nhau. Cc thao tc ny cho

ta cu trc trc tip loi II chuyn vnh sau:

Hnh 1-24 Cu trc blc IIR chuyn vtrc tip loi II

Cui cng ta thy rng cu trc chuyn vtrc tip loi II i hi sphp nhn, php

cng v s nhging nh cu trc trc tip loi II ban u.

1.4.2 Cu trc blc sI I R dng ni tip

Gi s ta xt mt h IIR bc cao c hm truyn t :

0

1

H(z)

1

M r

r

r

Nk

k

k

b z

a z

(1.4.2.1)


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Khng mt tnh tng qut nu ta gi thit N M. C th phn tch h thnh cc h

con bc hai ni tip, v th c th biu din Hz didng:

1

( )k

k

k

H z G H z

y k l phn nguyn ca1

,2

ZN H c dng tng qut :

1 2

1 2

1 2

1 2

1

1k k

k

k k

b z b z H z

a z a z

(1.4.2.2)

V G l tham s khuch i c nh, xc nh theo (1.4.2.1) l G= 0b . Cng ging

trng hp h FIR theo cu trc ni tip, tham s khuch i G c th c phn b bng

nhau chok mt lc sao cho G = 1 2 3......... kG G G G

Cc h s kia v kib . Trong cc h con bc hai l thc, iu ny ni ln rng, khi hnh

thnh cc h con bc hai hay cc tha s bc hai trong (1.4.2.2) ta phi nhm cc cp cc

khng lin hp vi nhau

Nu M > N, mt h thng con bc hai s c cc h s t bng khng, ngha l hoc

2 0kb hoc 1 0kb hoc c 1 2 0k kb b i vi mt s k no y .

Hn na nu N l l, mt trong cc h con, chng hnk

H zphi c2

0k

a , v th h

thng con l bc nht. duy tr tnh modul khi thc hin, thng thng ngi ta dng h

thng con bc hai c bn trong cu trc ni tip v c mt vi h s ly gi tr khng mt

s h s con

Mi h s con bc hai vi hm truyn t c dng (1.4.2.2) c th c th hin theo

dng trc tip loi II.V c nhiu cch ghp cp cc cc v khng ca Hz thnh cc mt bc

hai ni tip v c mts xp th t cc h thng con, nn c th thu c cc cu trc ni

tip l tng ng i vi cp chnh xc nht nh, cc th hin khc nhau mt cch ng

k khi c thc hin vi cc php s hc c chnh x nht nh

Dng tng qut ca cu trc ni tip c minh ha hnh 1-25


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Hnh 1-25 Cu trc ni tip cc hthng bc II v thhin mi mt lc bc II

1.4.3 Cu trc blc sI I R dng song song

Cu trc dng song song ca b lc IIR c th c hnh thnh t biu din phn thc

ca H( z ) khng mt tnh tng qut nu ta li gi thit rngN M v cc cc l phn bit.

Sau , theo thc hin khai trin phn thc ca H(z), ta li c :

11 1

Nk

z k k

AH C

p z

(1.4.3.1)

y ta c kp l cc cc kA l cc h s (phn d ) trong khai trin phn thc v

hng s C = NN

b

a, cu trc do (1.4.3.1) to ra c trnh by hnh 1-27.N gm mt dy

cc b lc n cc song song .

Ni chung , mt s cc ca Hz c th l gi tr phc.

Trong trng hp nh th cc h s 1 1 0k kb a kA tng ng l phc. trnh vic

nhn s phc, ta c th ghp cc cp cc phc lin hp phc hnh thnh cc h con hai

cc. Ngoi ra, ta c th lin kt mt cch ty cc cp cc gi tr thc to ra cc h con

hai cc. Mi h con ny c dng :


60/92

47

0

1

1

1 2

1 2

( )1

k k

k

k k

b b zH z

a z a z

y, cc h s kib v kia l tham s h thng ly gi tr thc. By gi hm trn c

th c biu din l :

1

( )N

k k

k

H z C H z

(1.4.3.2)

Vi k l phn nguyn ca (N+1)/2 khi N l l, mt trong ( )kH z tht s l mt h cc

( ngha l 1 1 0k kb a )

C bit, cc mt bc hai, l cc khi c bn ca H(z), c th c thc hin theo dng

trc tip hoc theo dng chuyn v trc tip minh ha trong hnh 1-27

Hnh 1-26 Cu trc song song ca hthng IIR

Hnh 1-27 Cu trc ca mt mt bc II trong thhin hthng IIR song song


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1.4.4 Cu trc blc I I R dng dn (mt co)

Gi s ta bt u vi h ton cc c hm truyn t :

1

1

1 1( )

( )1 ( )N

Nk

k

H z

A za z z

Cu trc dng trc tip ca h thng ny nh sau

Hnh 1-28 Cu trc dng trc tip ca hton cc

2 CHNG2. THIT KMCH TCH HP SSDNG

CNG NGHFPGA

2.1 Tng quan vcng nghFPGA

2.1.1 Gii thiu vFPGA

FPGA l vit tt ca "Field Programmable Gate Array", l vi mch dng cu

trc mng phn t logic m ngi dng c th lp trnh c, c th thc hin cc tnh

nng logic thng qua my tnh ca mnh vi gi r, v c th xa i vit li nhiu ln.

Xilinx l cng ty u tin bn ra FPGA v lun chim th phn ln nht. Ngoi ra cn c

Alterna, Lattice, Actel, QuickLogic. Nhiu nh sn xut hin ang cungcp rt nhiu cu

trc vphng php x l khc nhau. V vy, vic chn mt cu trc v mt phng php

x l c th p ng c cc yu cu v chc nng v n nh, i vi mt hthngtrong thc t l vn mang tnh quyt nh. Thit b logiclp trnh c c pht

minh ln u vo cui thp k 1970 v ngay lp tc tr ln ph bin trong ngnh

cng nghip bn dn. Ngoi kh nng lp trnh a dng, cng ngh ny cn c thi gian


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49

snxut nh nn c kh nng cnh tranh thng mi rt ln. Hn na, vic thit k vi

n kh d dng v n c kh nng lp trnh li nhiu ln.

FPGA c thit k u tim bi Ross Freeman, ngi sng lp cng ty Xilinx

vo nm 1984, kin trc mi ca FPGA cho php tnh hp s lng tng i ln cc phn

tbn dn vo 1 vi mch so vi kin trc trc l CPLD (Complex Programmable

Logic Device).im tng ng ca CPLD v FPGA l ch chng u bao gm mt s

lngtng i ln cc phn t logic kh trnh. Tuy nhin mt tch hp th khc nhau,

mt cng logic ca CPLD nm trong khong t vi nghn n hng chc nghn, trong

khi vi FPGA th mt tch hp c hng chc nghn cho n vi triu.

FPGA v CPLD c rt nhiu im khc bit tuy nhin kin trc l im khc bit chnh

gia CPLD v FPGA. CPLD c kin trc gii hn mt mc no , n baogm mt

hoc nhiu di logic sum-of-products kh trnh v c cung cp mt stng i nhcc thanh ghi c ng b. iu ny lm cho CPLD tr nn khng c mm do lm,

nhng b li tr timing li d don hn v tc kt ni logic cng caohn FPGA. Vi

FPGA, th kin trc theo mt cch khc tri hn hn CPLD bi v FPGA s dng cc lin

kt ni. iu ny khng nhng to cho n mm do hn rt nhiu mcn lm tng phc

tp trong tht k.

2.1.2 Kin trc chung ca mt FPGA

Cu trc tng th ca FPGA bao gm:- Cc khi logic c bn lp trnh c.

- H thng mch lin kt.

- Cc khi vo/ra.

- Cc phn t thit k sn khc.


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Hnh 2-1Cu trc tng thca mt FPGA

Khi logic c bn lp trnh c

Hnh 2-2Khi Logic

FPGA cha trong n rt nhiukhi logic c th ti cu hnh CLB (Configurable Logic

Blocks) c lin kt vi nhau thnh bng cc lin kt kh trnh

(Programmable Interconnect). Cc khi vo ra c phn b xung quanh chip to thnh

cc lin kt vibn ngoi. Bn trong khi logic CLB c bng LUT (Look-Up Table) v cc

phn t nh(FlipFlop hoc b cht). LUT (Look up table) l khi logic c th thc hin

bt k hm logic no t 4 u vo, kt qu ca hm ny ty vo mc

ch m gi ra ngoi khi logictrc tip hay thng qua phn t nh flip-flop.

Trong ti liu hng dn ca cc dng FPGA ca Xilinx cn s dng khi

nimSLICE, 1 Slice to thnh t gm 4 khi logic, s lng cc Slices thay i t vinghn n vi chc nghn ty theo loi FPGA.

Nu nhn cu trc tng th ca mng LUT th ngoi 4 u vo k trn cn h trthm

2 u vo b xung t cc khi logic phn b trc v sau n nng tng s u voca LUT

ln 6 chn. Cu trc ny l nhm tng tc cc b s hc logic.


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Hthng mch lin kt

Mng lin kt trong FPGA c cu thnh t cc ng kt ni theo hai

phngngang v ng, ty theo tng loi FPGA m cc ng kt ni c chia thnh

cc nhm khc nhau, v d trong XC4000 ca Xilinx c 3 loi kt ni: ngn, di v rt di.

Cc ng kt ni c ni vi nhau thng qua cc khi chuyn mch lp trnh

c(programable switch), trong mt khi chuyn mch cha mt s lng nt chuyn

lptrnh c m bo cho cc dng lin kt phc tp khc nhau.

Cc phn tthit ksn khc

Ngoi cc khi logic ty theo cc loi FPGA khc nhau m c cc phn t tch

hp thm khc nhau, v d thit k nhng ng dng SoC, trong dng Virtex 4,5 ca

Xilinx c cha nhn x l PowerPC, hay trong Atmel FPSLIC tch hp nhn ARV, hay

cho nhng ng dng x l tn hiu s DSP trong FPGA c tch hp cc DSP Slide lbnhn cng tc cao, thc hin hm A*B+C, v d dng Virtex ca Xilinx cha t

vi chc n hng trm DSP slices vi A, B, C 18-bit. .

2.2 Ngn nglp trnh VHDL

Ngn ng m t phn cng (HDL) l ngn ng lp trnh phn mm dng mhnh

hat ng mong mun ca phn cng. C hai kha cnh m HDL to iu kin m t

phn cng: m hnh hnh vi tru tng v m hnh cu trc phn cng.M hnh hnh vi

tru tng. Ngn ng m t phn cng to iu kin d dng chovic m t tru tnghnh vi ca phn cng i vi cc mc ch c t (ch r chi tit k thut). Hnh vi ny

khng ch b chi phi bi cc kha cnh cu trc hoc thit k ca h phn cng.

M hnh cu trc phn cng. Cu trc phn cng c kh nng c m hnh

trong ngn ng m t phn cng m khng cn quan tm n hnh vi thit k.

Nm 1980 b Quc phng M (DOD) mun thc hin vic thit k mch t dn

chng,mun theo ui mt h phng php thit k tng qut v c th s dng li c

vi cccng ngh mi. R rng c nhu cu cho mt ngn ng lp trnh chun m tchcnng v cu trc ca cc mch s i vi vic thit k vi mch (IC). Sau DOD

ti tr cho mt d n thuc chng trnh vi mch c tc rt cao VHSIC (very high

speed integrated circuit) to ra ngn ng m t phn cng chun. Kt qu l d n ny


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to ra ngn ng m t phn cng VHSIC hay thng c gi l VHDL (VHSIC

Hardware Description Language -Ngn ng miu t phn cng VHSIC) nh hin nay.

VHDL c xem nh l s kt hp ca cc ngn ng sau: ngn ng tun t, ngn

ng ng thi, netlist, nh thi, m phng. Do cu trc VHDL cho php th hin cch

thc thc hin theo kiu song song hay tun t ca mt h thng s c hoc khng c

timing. N cng cho php v m hnh mt h thng bng cc lin kt ni ca cc thnh

phn.

VHDL c dnh cho tng hp mch (synthesis) cng nh m phng

mch(simulation). D VHDL c th m phng mt cch y , nhng khng phi tt c

cc cu trc u c VHDL tng hp.

2.2.1 Cc u im ca VHDL

- Chng trnh trong VHDL c th c vit theo nhiu cu trc khc nhau:

Ngunhin, tun t, ni chn, nh thi ch r, ngn ng sinh dng sng.

- VHDL l mt ngn ng phn cp, h thng s c th c m phng nh mt ktni

cc khi m cc khi ny c thc hin bi cc khi con khc nh hn.

-

Cung cp mt cch mm do cc phng thc thit k trnxung, di ln, hoct

hp c hai.

- Cung cp c hai mode ng b v khng ng b.

-

Linh hot trong k thut m phng s nh s dng biu trng thi, thut ton,cchm Boolean.

- C tnh i chng: VHDL c pht trin di s bo tr ca chnh ph M vhin

nay l mt tiu chun ca IEEE. VHDL c s h tr ca nhiu nh sn xutthit

b cng nh nhiu nh cung cp cng c thit k m phng h thng.

-

VHDL cung cp 3 kiu mu vit khc nhau: structural, dataflow v behavioral.

- Khng gii hn v ln ca thit k khi s dng ngn ng.

-

VHDL hon ton c lp vi cng ngh ch to phn cng. Mt m t h thngdng

VHDL thit k mc cng c th c chuyn thnh cc bn tng hp mch khcnhau tu thuc cng ngh ch to phn cng mi ra i nc th c pdng ngay

cho cc h thng thit k .

-

Kh nng nh ngha kiu d liu mi cung cp mt cng c hu hiu cho thit kv

m phng cng ngh mi vi mt mc rt cao.


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2.2.2 Cu trc mt m hnh hthng sdng ngn ngVHDL

VHDL l ngn ng m t phn cng do vy m n c th c s dng lm

m hnh ca mt h thng s. H thng s c th n gin l cc cng logic hay phc tp

nhmt h thng hon chnh. Cc khi xy dng nn ngn ng VHDL gi l cc khi

thitk. C 3 khi thit k chnh:

- Khai bo Entity (Thc th)

- Khai bo Architecture (Kin trc)

- Khai bo Configuration (Cu hnh)

- i khi ta s dng cc gi (Packages) v m hnh kim tra hot ng ca h thng

(Testbench).

2.3

Cc thao tc lp trnh trn Altium Designed.

To Project mi:File / New / Project / FPGA Project

Hnh 2-3 Cc thao tc to project mi trong Altium designed

.

Add fi le Vhdl

Kch chut phi => Add New to Project / VHDL Document


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Hnh 2-4 Cc thao tc add file chng trnh VHDL.

Vit chng trnh

Bin dch chng trnh

Hnh 2-5 Thao tc bin dch chng trnh


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2.4 NanoBoard NB2DSK01

B cng c pht trin FPGA, vi x l, h nhng Altium Desktop Nanoboard NB2,

c kh nng cu hnh phn cng ph hp vi nhu cu v mc ch thit k

2.4.1

Kin trc tng quanPhn cng, kit NanoBoard NB2DSK01 pht trin c kh nng cu hnh tn dng sc

mnh ca nhng chip kh trnh gi r, dung lng cao - cho php pht trin v trin khai

h thng nhanh chng.

H tr cc chc nng thit k FPGA v hon ton ng b vi h thng thit k in t hp

nht Altium Designer.

Gim st thi gian thc cng sut tiu th v nh gi phn tch cho ton b h thng

T ng nhn dng v cu hnh cc bo mch FPGA con v cc bo mch ngoi vi Vi NB2, khng cn cn thit phi thit k trong mi trng m phng hoc phi lm nhiu

mch mu trong qu trnh pht trin, thay vo l cng vic thit k, lp trnh m phng

online trn chip.

Mt s kin trc ni bt ca NanoBoard NB2DSK01

-

ng dng ring r ,cm pht vo bo mch ngoi vi , hon thnh h thng linh ng

-

Cm pht vo bo mch con , iu ny cho php c c mc tiu rng ca FPGA v

thit b b x l trong my tnh- PC tc cao ni lin vi nhau thng qua USB 2.0 , iu ny cho php vic ti

xung v chnh li

-

Gn lin m sc ca ngi ni ti m thanh ra

- Tch hp TFT tip xc vi mn nh lm cho ng dng c tng tc d dng

2.4.2 Thng skthut NB2DSK01

- H tr nhiu FPGA v vi x l ca cc hng sn xut chip khc nhau thng qua gii

php s dng cc bo mch con c th tho ra, lp vo- T ng nhn bo mch con v cc bo mch ngoi vi, cu hnh plug-and-play

- ng truyn kt ni vi my tnh tc cao qua cng USB 2.0 cho php np v

debug nhanh hn
http://techdocs.altium.com/display/HWARE/Desktop+NanoBoard+NB2DSK01http://techdocs.altium.com/display/HWARE/Desktop+NanoBoard+NB2DSK01


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- B iu khin NanoTalk qun l thi gian thc truyn thng ring vi Altium

Designer, bo mch v cc NanoBoard firmware s dng mt b iu khin Xilinx

Spartan-3 (XC3S1500-4FG676C) vi PROM cu hnh Flash, h tr chun JTAG

- Tch hp mn hnh cm ng mu TFT, tng tc trc tip vi b iu khin

NanoBoard v firmware-

u cm i User Board h tr JTAG tng tc v pht trin vi cc bo mch

khc

- u cm Master-Slave pht trin chui NanoBoard, cho php pht trin h thng

a FPGA

- ng h xung nhp c th iu chnh,t 6 n 200 MHz, cho cc FPGA

- ngh thi gian thc SPI Real-Time Clock vi pin 3V back-up

-

H m thanh analog Stereo vi b khuch i cht lng cao on-board, mixer, u

vo/ra v loa stereo

- Bn knh ADC 8 bit v DAC 10 bit, tng thch I2C

- u c th SD h tr thm cc cng vo ra, kh nng np vo nhiu file s

dng

- Ngun 5V DC i c th ni cho mt chui cc Nanoboard. Cc im test trn

board, 4 im t

-

B nh trong bo mch cho b iu khin NanoTalk bao gm hai SRAM 256K x

16chung bus, hai SDRAM 256M (16M x 16) chung bus, mt b nh Flash

3.0V256M (32M x 16) chung bus, hai SRAM 256K x 16 c lp

- Mt sgiao tip truyn thng chun: ni tip RS-232, CAN, PS/2 mini-DIN

-

Cc n LED v cng tc a mc ch

- Cc nt n kiu PDA, c thnh ngha sdng nh cc u vo chc nng trong

thit k

-

Nt Home/ ResetHome cho php firmware iu khin TFT panel; Reset skhi

ng li chc nng Nanoboard

- H cm bin cng sut cho php gim st cng sut tiu thca hthng v ca

chip.

-

Bnhnhn dng bo mch (Board ID)H1-Wire ID cho php nhn dng cc bo

mch FPGA conv cc bo mch ngoi vi.


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Hnh 2-6 Hnh nh ca NanoBoard NB2DSK01

3

CHNG 3. THIT KBLC SSDNG FPGA

3.1 Bi ton thit k

Thit k v thi cng b lc s IIR s dng FPGAvi cc thng s:

- Tn sct di thng: p =0.5

- Tn sct di chn: s =0.6

-

Suy hao di chn: As=50 dB

- gn di thng: Rp =0.5 dB

Lachn hng thit k: Thit k da vo b lc Butterworth v php bin i

song tuyn.

C hai hng thit k:

- Hng th nht: s dng trc tip cc thng s k thut yu cu thit k blc

s thng thp Analog Butterworth, sau bin i song tuyn tnh thu c b

lc s thng thp.

-

Hng th2: Sdng mt blc sthng thp thit k trc (dng blc

Butterworth v bin i song tuyn), sau thc hin php chuyn i bng tn thu

c blc thng thp sc thng skthuttheo yu cu.


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Di y sthit k theo hng thnht, cn hng thhai thc hin tng t, sau

sdng cng thc trong phn Php bin i bng tn (cui Phn II) chuyn

i Lowpass sang Lowpass.

3.2 Tnh ton thit k

Chn chu k ly mu T=1

Chuyn i p , s (tnh ton p,s)

2 0.5tan 2 tan 2

2 2

p

pT

(rad/s)

2 0.6tan 2 tan 2.750

2 2s

sT

(rad/s)

Thit k blc Ha (s) tha mn ch tiu ny:

- Tnh bc ca b lc:

Bc b lc: /10 /10 0.5/10 50/1010 10

10 10

log 10 1 / 10 1 log 10 1 / 10 122

2log ( / ) 2log (2 / 2.750)

p sR A

p s

N

- Tn s ct:

2*22 0.5/10/1022

2.110 110 1p

p

c RN

(rad/s)

Hay 2*22 50/10/102

2.7502.1

10 110 1ss

cAN

(rad/s)

Ta c : c=2.1 (rad/s)

p ng bin : 22 2*22

44

44

1 1 1| (j ) |

1111 2.12.1

a N

c

H

2

/44 44

44 44

1 1(s)H ( ) | ( ) | |

1 11 / 1

2.1 2.1

a a a s jH s H j

s j s


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Hnh 3-1 Hnh nh m phng nghim ca mu thc Ha(s)Ha(-s) trn matlab

222.1( ) (s)

12 13 ... 32 33a aH j H

s s s s

Trong s12,s13,,s33l nghim ca mu thc Ha(s)Ha(-s) na mt phng bn tri

Xc nh H(z): 1 1

1 1

2 1 12

1 1a a

z zH z H H

T z z

Nh vy ta nhn c H(z) l mt hm hu t theo Z-1

3.3

Thut ton v chng trnh Matlab


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3.3.1 Lu thut ton

Be in

Nhp cc ch

tiu

11000;Ts

s

FF

2tan

2

p

pT

2tan

2s

sT

Bin i song tuyn thu c H(z)

-Dng trc tip : [b,a]=bilinear(cs,ds,Fs)-Dng ghp tng : [C,B,A]=dir2cas(b,a)

Tnh ( )aH s

[cs,ds]=afd_butt ,( , , )p s s pA R

Tnh p ng bin

[db,mag,pha,grd,w]=freqz_m(b,a)

Tnh gi tr

As

v R thc t

- Vmt phng nghim

phc s-plane v z-plane.

- Vp ng bin ,

pha ca blc thit k.

END

M rng

a tn hiu vo x vi

max2

sFf

Filter

(va thit k)

Tn hiu u ra y

Phn tch phtn hiu x

v y dng bin i FFT

V th

-Tn hiu vo theo thi gian

-Tn hiu ra theo thi gian-Ph tn hiu

-


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3.3.2 Chng trnh matlab

Cc hm sdng trong chng trnh

-

Hm [cs,ds] = afd_butt(OmegaP,OmegaS,Rp,As)

thit k blc thng thp analog Butterworth, cho bi cc ch tiu ca n.

>> function [b,a] = afd_butt(Wp,Ws,Rp,As);

% Analog Lowpass Filter Design: Butterworth

% -----------------------------------------% [b,a] = afd_butt(Wp,Ws,Rp,As);

% b = Numerator coefficients of Ha(s)

% a = Denominator coefficients of Ha(s)

% Wp = Passband edge frequency in rad/sec; Wp > 0

% Ws = Stopband edge frequency in rad/sec; Ws > Wp > 0

% Rp = Passband ripple in +dB; (Rp > 0)

% As = Stopband attenuation in +dB; (As > 0)

%

if Wp


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fprintf('\n*** Butterworth Filter Order = %2.0f \n',N)

OmegaC = Wp/((10^(Rp/10)-1)^(1/(2*N)));

[b,a]=u_buttap(N,OmegaC);

-

Hm[b,a] = u_buttap(N,Omegac) (sdng bn trong hm afd_butt)

thit k mt b lc Analog Butterworth cha chun ho vi c ty bc N

function [b,a] = u_buttap(N,Omegac);

% Unnormalized Butterworth Analog Lowpass Filter Prototype

% --------------------------------------------------------% [b,a] = u_buttap(N,Omegac);

% b = numerator polynomial coefficients of Ha(s)

% a = denominator polynomial coefficients of Ha(s)

% N = Order of the Butterworth Filter

% Omegac = Cutoff frequency in radians/sec

%

[z,p,k] = buttap(N);

p = p*Omegac;

k = k*Omegac^N;

B = real(poly(z));

b0 = k;

b = k*B;

a = real(poly(p));

-

Hm [b,a] = bilinear(cs,ds,Fs)

Bin i song tuyn chuyn Ha(s) thnh H(z)

b = cc h s t thc ca H(z)

a = cc h s mu thc ca H(z)

cs = cc h s t thc ca Ha(s)


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ds = cc h s mu thc ca Ha(s)

Fs = tn s ly mu

- Hm [db,mag,pha,grd,w] = freqz_m(b,a);

Tnh bin tng i (dB), bin tuyt i, pha, nhm tr, di mu tn s t hm hthng H(z) c h s t thc l b, h s mu thc l a .

function [db,mag,pha,grd,w]=freqz_m(b,a);

% Modified version of freqz subroutine

%..................................

% [db,mag,pha,grd,w]=freqz_m(b,a);

% db=Relative magnitude in dB computed over 0 to piradians% mag=absolute magnitude computed over 0 to pi radians

% grd= Group delay over 0 to pi radians

% w=501 frequency samples between 0 to pi radians

% b=numerator polynomial of H(z) (for FIR: a=h)

% a=demonitor polynomial of H(z) (for FIR: a=[1])

%[H,w]=freqz(b,a,1000,'whole');

H=(H(1:1:501))';w=(w(1:1:501))';

mag=abs(H);

db=20*log10((mag+eps)/max(mag));

pha=angle(H);

grd=grpdelay(b,a,w)- Hm[C,B,A] = dir2cas(b,a): Chuyn i dng trc tip thnh dng ghp tng.

function [b0,B,A] = dir2cas(b,a);

%DIRECT-form to CASCADE-form conversion (cplxpair version)


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%.........................................................

%[b0,B,A]=dir2cas(b,a)

%b0=gain coefficient

%B= K by 3 matrix of real coefficient

%A= K by 3 matrix of real coefficient

%b = numerator polynomial coefficient of DIRECT form

%a = numerator polynomial coefficient of DIRECT form

% compute gain coefficient b0

b0 = b(1); b = b/b0;

a0 = a(1); a = a/a0;

b0 = b0/a0;

M = length(b);N = length(a);

if N > M

b=[b zeros(1,N-M)];

elseif M > N

a=[a zeros(1,M-N)];N=M;

else

NM=0;

end

%

K=floor(N/2);B = zeros(K,3);A = zeros(K,3);

if K*2 == N;

b=[b 0];

a=[a 0];

end


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%

broots = cplxpair(roots(b));

aroots = cplxpair(roots(a));

for i=1:2:2*K

Brow = broots(i:1:i+1,:);

Brow = real(poly(Brow));

B(fix((i+1)/2),:) = Brow;

Arow = aroots(i:1:i+1,:);

Arow = real(poly(Arow));

A(fix((i+1)/2),:) = Arow;

End

Mt s hm khc:

Hm [bz,az] = zmapping(bZ,aZ,Nz,Dz): Chuyn i bng tn thu c cc

blc chn tn khc tblc thng thp sthit k c.

Hm [ha,x,t] = impulse(cs,ds): p ng xung ha(t) ca blc Analog

Hm y = filter(b,a,x)- Lc tn hiu x qua h thng H(z) c h st thc l b, hsmu thc l a.

-

y l tn hiu thu c sau khi lc

Hm fft(x,n)

- Bin i Fourier nhanh tn hiu x vi n im.

-

y ng dng phn tch ph tn hiu vo ra.

Hm zplane(num,den): v im zeros v im poles trn mt phng phc

Hm freqz(b,a): v p ng bin (dB) v p ng pha ()

Chng trnh

clear all

close all

clc


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% Nhp cc thng skthut

wp = input(' - Tan so cat canh dai thong wp =' );

ws = input(' - Tan so cat canh dai chan ws =');

As = input(' - Suy hao dai chan As =');

Rp = input(' - Do gon song dai thong Rp =');

%% Thit kthng thp

%%

Fs = 1000;

T = 1/Fs;

f_pass = wp*Fs/2/pi;

f_stop = ws*Fs/2/pi;

fprintf('\nDai chuyen tiep: [%5.1f,%5.1f]Hz\n',f_pass,f_stop);

OmegaP = (2/T)*tan(wp/2);

OmegaS = (2/T)*tan(ws/2);

[cs,ds] = afd_butt(OmegaP,OmegaS,Rp,As);

%% Bin i song tuyn

%%

[b,a] = bilinear(cs,ds,Fs);

[db,mag,pha,grd,w]=freqz_m(b,a);

[C,B,A] = dir2cas(b,a)

delta_w=pi/500;

Asd = floor(-max(db(ws/delta_w+1:500)))

Rpd = -min(db(1:wp/delta_w+1))

%% Dap ung xung

[ha,x,t] = impulse(cs,ds);


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[delta,n] = impseq(0,0,50);

h=filter(b,a,delta);

%% Cc tn hiu vo

%%

nth = 0:1/Fs:2;

f1=150; f2=200; f3=280; f4=350;

TH1 = 2*sin(2*pi*f1*nth);

TH2 = 2*cos(2*pi*f2*nth);

TH3 = 2*sin(2*pi*f3*nth);

TH4 = 2*cos(2*pi*f4*nth);

TH = TH1+TH2+TH3+TH4;

%% Lc tn hiu

y = filter(b,a,TH); % y l tn hiu ra

%% Phn tch phtn hiu

spec_in=abs(fft(TH,512)); spec_in = spec_in(1:257); % chly 1 na

spec_out=abs(fft(y,512)); spec_out = spec_out(1:257);

f = Fs*[0:256]/512;

%% Mat phang nghiem phuc

figure(1)

subplot(2,1,1); zplane(cs,ds); title('s-plane','fontsize',12);

subplot(2,1,2); zplane(b,a); title('z-plane','fontsize',12);

%% Vp ng bin

figure(2);

subplot(2,2,1);

plot(w/pi,mag,'Linewidth',2);grid


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title('Magnitude Response','fontsize',12);

ylabel('|H|'); xlabel('w/pi');

axis([0 1 -0.1 1.1]);

set(gca,'XTickMode','manual','XTick',[0;wp/pi;ws/pi;1]);

set(gca,'YTickMode','manual','YTick',[0;1]);

subplot(2,2,2);

plot(w/pi,db,'Linewidth',2);grid ;

title('Magnitude in dB','fontsize',12);

ylabel('Decibels'); xlabel('w/pi');

axis([0 1 -Asd-3 2]);

set(gca,'XTickMode','manual','XTick',[0;wp/pi;ws/pi;1]);

set(gca,'YTickMode','manual','YTick',[-Asd;0]);

subplot(2,2,3);

plot(t,ha);grid;

title('Impulse Response Analog','fontsize',12);

axis([0 50*T floor(min(ha))-50 ceil(max(ha))+50]);

subplot(2,2,4)

stem(n,h);grid

title('Impulse Response Digital','fontsize',12);

axis([0 50*T -0.5 0.5]);

figure(3)

freqz(b,a); %Ve dap ung bien do va dap ung pha trn 1 cua so

%% Vtn hiu u vo, u ra

figure(3)

Sam = 100;


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subplot(2,2,1)

plot(nth(1:Sam),TH(1:Sam));

title('Input Signal','fontsize',12);

axis([0 nth(Sam) min(TH)-0.5 max(TH)+0.5]);

subplot(2,2,2)

plot(nth(1:Sam),y(1:Sam));

title('Output Signal','fontsize',12);

axis([0 nth(Sam) min(TH)-0.5 max(TH)+0.5]);

% Vphtn hiu

subplot(2,2,3)

plot(f,spec_in);%grid

title('Spectrum of the Input Signal','fontsize',12);

xlabel('Frequency (Hz)');

ylabel('Magnitude');

axis([0 Fs/2 -1 max(spec_in)+2]);

set(gca,'XTickMode','manual','XTick',[0;f1;f2;f3;f4;Fs/2]);

subplot(2,2,4)

plot(f,spec_out);%grid

title('Spectrum of the Output Signal','fontsize',12);

xlabel('Frequency (Hz)');

ylabel('Magnitude');

axis([0 Fs/2 -1 max(spec_in)+2]);

set(gca,'XTickMode','manual','XTick',[0;f1;f2;f3;f4;Fs/2]);


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kt qu

- Tan so cat canh dai thong wp = 0.5*pi

- Tan so cat canh dai chan ws = 0.6*pi

Documents

thiet ke mach loc so iir su dung matlab