knjiga dos i

8/2/2019 Knjiga DOS I

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Analogna

obdelava

signala

Analogni

vhodni signal

(zvezni)

Analogni

izhodni signal

A/Dpretvorba

Analognivhod

Analognisignal

Digitalni

signalni

procesor

D/Apretvorba

Digitalni

vhodni signal

Digitalni

izhodni signal


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y

x

z

s1

s2

s3

s(t)


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t

1

2

te -te2

t

1

)(tu

0

stopnica

tt

te


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0t

)(t


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0 1-1

0

Re os

Im os


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)(txa

)cos(QAFTp /1

0t


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Fs

=1/T

x(n) = xa(nT)x

a(t)

zvezni -

analogni signal

asovno

diskretni signal

xa(t) x(n) x(n)

xa(t)

nt


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F

f wp

2

1

p2

1-

2

sF

2sF-

sF

sF


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Tp2

)(WSW

NN

S S2W WSS2W 0

NN NS W S

T

1

)(WvzX

S

)(WaX

W


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WNN

NN NS W S

)()( Wvzs XX

S

)(WaX

WNS W0

)( NSN c W

c

)(WrH

W0

T

c

WNN

)(WrX

- -n nTtts )()( d)(

WrH

)(txa )(txr

)(WvzX

W


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T 2T 3T 4T-T-2T-3T-4T

h tr( )1

t

0 p /T-p /T

Hr

( )

W

0 T

x n[ ]

2T 3T

0 T 2T 3T

0 T 2T 3T

0 T 2T 3T

Pretvorbe izniza v vlak

Idealno nizko

sito ( )Hr wx n[ ] x ts( ) x tr( )

Periodavzorenja T

a)

b)

c)


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x ta( )

t

x ta( )

x ts( )

t

T

x tr( )

T 2T 3T 4T 5T

t


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A/D)(txa

T

)(txa

)(nTxa

)(nxBZadr evalnovezje


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)(0 tx)(txs)(txc

- )()( nTtts d

)(0 th

Zadr evalno

vezje

)(txc)(0 tx

tT5 T7T3T

T5T7 T3 T

A/D)( nx)(txa )(nx )( nxBKvanti-

zator

Koder

T


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)( xQx =

DD2 D

3

D4

2

D2

3D

27

D2

5D x

23

D-2

5D-

27

D-


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T

n

nnx 9.0)( =ttx 9.0)( =

n

)(nxqt

a tx 9.0)( =

DObmoje

kvantizacijeKorakkvantizacije


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A/D)(ny)(txa )(nx )(nyrDiskretni

sistemD/A

T T


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H)(ny)(nx


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H][][ 21 nbxnax + ][][][ 21 nbynayny +

][1 nx

][2 nx

][ny


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LTI

H

][nx ][ny

]1[ -nx ]1[ -nyLTIH


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H1

Hzaporedna

)(1 ny)(nx )(ny

Hvzporedna

)(1 ny

)(nx

)(2 ny

)(ny

a) b)

H2

H1

H2


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2

1

3

4

5

-1-2-3-4-1

1

2

3 4 5k

h(k)

2

1

3

4

5

-1-2-3-4-1

1 2 3 4 5k

h(k)

2

1

3

4

5

-1

-2

-3-4-1

1 2 3 4 5k

h(-k)

0n 2

1

3

4

5

-1-2-3-4-1

1 2 3 4 5k

)(0 kv

2

1

3

4

5

-1

-2-3-4 -1 1 2 3 4 5

k

h(1-k)

1n2

1

3

4

5

-1-2-3-4 -1 1 2 3 4 5

k

)(1 kv

2

1

3

4

5

-1-2

-3

-4-1

1 2 3 4 5k

h(-1-k)

1n 2

1

3

4

5

-1-2-3-4-1

1 2 3 4 5k

)(1 kv-

preslikava


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)(1 ny

)(nx

)(2 ny

)(nyh

1

h2


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n

)(ny

)1( -nypomnilnika

enota

Z-1

n1

1

)(ny

b) rekurziven

F[x(n), x(n-1),

..., x(n-M)]

)(nx)(ny)(nx

a) nerekurziven

Z-1

F[y(n-1), y(n-2),

..., x(n),..., x(n-M)]


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)(nx b0

b1

-a1

Z-1

)(nvZ-1

)(ny

H1

H2

)(nx b0

b1

-a1

Z-1

)(nwZ-1

)(ny

H1

H2

)(nx b0

b1

-a1

Z-1

)(nw )(ny

x(n-1)


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)(nx b0

b1

-a1

Z-1

)(nvZ-1

)(ny

H1

H2

Z-1

bM-1

bM

-aN-1

-aN

Z-1


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)(nx b0

-a1

Z-1

)(nw )(ny

w(n-1) b1

w(n-M)b

M-a

N-2

Z-1

-aN-1Z-1

-aN


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)(nx b0

-a1

Z-1

)(nw )(ny

b1Z

-1

b2

-a2

b0

Z-1)(nx

)(nyb

1

Z-1

b

2


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)(nx )(ny-a

2-a

1

Z-1 Z-1

b0


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Z-1)(nx

)(ny

Z-1

Z-1

1

1M +

Z-1)(nx

)(ny

Z-1

Z-1

1

1

+MZ-1

)1( -Mnx

)1( -ny


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)(tx

2

pT

2

pT-t

)(txp

2

pTpTpT

2

pT-t


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)(tx

2

t- 0t

2

t

A

)(FX

t1

t2

t1-t

2- 0F


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)(wX

wp0 cc

c

p

pw c

0c

p- n

)(nx


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)(1 wX

1N

)(3 wX

3N

)(7 wX

7N

)(15 wX

15N

)(50

wX

50N

)(70

wX

70N


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0 5 10 15 20

0 5 10 15 20

n

n

)(5.0)( nunx n=

)()5.0()( nunx n-

5.0,cos21

1)(

2=+ aaaSxx w

5.0,cos21

1)(

2-+ aaaSxx w

p p2

p-2

p0

p p2

p-2

p0

4

1

2

3

4

2

3

1

a) b)


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)(nx

0 1 2 3 L-2 L-1n


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|)(| wX

p p2

p-2

p0

4

1

2

3

5

w

)(w

2

p-p

p p2

p- 2p

2p

p

w


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xI(n)

Re

Im

|x(n)

|

xR

(n)

x(n)


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Re

Im

|X(w)|

XR

(w )

XI(w ) X(w )

X*(w )

X(w )


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)(wX

)( 0-Xp 2/ p2/ p22 0 w

wp p p22 0 0 02 w+02 w+


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