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7/21/2019 Analogna televiz
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Analog Analognana televitelevizzii ja ja● Uvod
● Analogni TV sustav
● Analiza slike s proredom
● Signali sinkronizacije● Kompozitni signal
● Dijelovi signala
● NTSC i PAL sustav
● Uzorkovanje TV signala
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TV sTV suusstavtav
A m p l i t u d e
Kamera Odašiljač
0
Scena Električni signal
Vizualni sustavPrijamnikTV slika
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Oko i osjet vidaOko i osjet vidaSclera
Optic nerve
Blind spot
Aqueous
humor
Vitreous humor
LensCorneaIris
Fovea
Retina
Glare limit
A d a p t a t i o n r a n g e
S u b j e c t i v e
b r i g h t n e s s
Scotopic
threshold
B b
Ba
Scotopic
Photopic
Log of intensity
0.5
1
2
4
8
1 1.5 2 3 4 6 8 1216 24
0.5
0.2
0.1
0.05
0.02
0.01
S e n s i b i l i t y t o c o n t r a s t
Temporal frequency (Hz)
S
p a t i a l f r
e q u e n
c y
( c y c l e
s / d e
g r e e )
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Analiza Analiza TV sTV slikelike
Broj linija po slici:
Ovisi o željenoj horizontalnoj rezoluciji
Broj slika u sekundi:
Nema treperenja > 50Osjećaj kretanja > 15
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VertiVertikalnakalna rezolucijarezolucija (1)(1)1 perioda
33.5 perioda po slici
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VertiVertikkalalnana rezolucijarezolucija (2)(2)
1 perioda
6.5 periodapo slici
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VertiVertikalnakalna rezolucijarezolucija (3)(3)
1 perioda
1.5 periodapo slici
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HorizontalHorizontalnana rezolucijarezolucija (1)(1)
1 perioda
33.5 periodapo slici
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HorizontalHorizontalna rezolucijana rezolucija (2)(2)
6.5 perioda
po slici1 slici
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HorizontalHorizontalnana rezolucijarezolucija (3)(3)
1 perioda
1.5 periodapo slici
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Princip proredaPrincip proreda TV sTV slikelike (1)(1)1/50s 1/50s 1/25s
1357
9111315
+ =
246
8101214
Neparna slika Parna slika Kompletna slika
C
BD
C A1
3
5
A
B
246
D
Neparne linije Parne linije Povratak linijeparne poluslike
Povratak linijeneparne poluslike
Broj linija: 625Broj slika : 25
Broj poluslika: 50dvije poluslike = 1 slika
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..1
3
5
7
9
11
13
15
17
19
2
4
6
8
1012
14
16
18
C
D B .
A
.
Princip proredaPrincip proreda TV sTV slikelike (2)(2)
Horizontalna analiza
Horizontalni povratni intervalVertikalni povratni interval
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TV signalTV signal -- B/WB/W
50
25
0
A m p l i t u d a
100
75
Maksimalna razin
sinkro signalHorizontalni
% Razina blokiranjapotisna razina
Razina bijelogVideo signal
Linija N
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SinkronizacijaSinkronizacija poluslikapoluslika
neparna
parna
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TV signal speTV signal spektar ktar -- B/WB/Wf h: Horizontalna (15.625)
f v: Vertikalna (50)
f 0f v 2f v f h 2f h
f 5 MHz0
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TV emitterTV emitter -- B/WB/W
Mic.
TV kamera
Audio
pojačalo.
FM
modulator
Nos..tona
RF
pojačalo.
Video
pojačalo
Si..
generator
kamerageneratora
Zbrajal
o
AM
modulator
Nosi.
slike
Video
R.F.
pojačalo.
Pojasni
filter
+
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0 1
1
0.5
0.5
R
e c e i v e
r
E m
i t t e r
X
Y
Y=X1/2.8
Y=X2.8
GaGammaa korekcijakorekcija
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TVTV prijamnikprijamnik -- B/WB/W
Tuner FI
Amplifier Detector
GACDelay
GAC
Video
Amplif.
Sound
detector
Sound
Amplif.
Sync
separator
Sync.
processing
Sync
processing
Line
oscilator
Field
oscilator
Line
output
Field
output
Limiter
Amplif.
TV t b jiTV sustav u boji
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R - Red G - Green B - Blue
TV sustav u bojiTV sustav u boji
+
RGB
Kamera Širina kanala je3 x 5 MHz = 15 Mhz
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Komponente signala bojeKomponente signala boje
RG
B
Y = 0.30R + 0.59G + 0.11B 5 MHz1 MHz
1 Mhz
Kamera u = 0.495 (B – Y)
v = 0.877 (R - Y)Širina kanala 7 Mhz
Y – Luminantni signal u = 0.495 (B – Y) v = 0.877 (R - Y)
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TVTV signal bojesignal boje (1)(1)
RG
B
Y = 0.30R + 0.59G + 0.11B 5 MHz1 MHz
1 Mhz
Kamera R - Y
B - YŠirina kanala 7 Mhz
R-Y = R - (0.30R + 0.59G + 0.11B) = 0.7R - 0.59G - 0.11B
B-Y = B - (0.30R + 0.59G + 0.11B) = -0.3R - 0.59G + 0.89B
Monitor Y
R - YB - Y
Y + R - Y = RY + G - Y = GY + B - Y = B
Prijamnik
G - Y = -(0.3/0.59)(R - Y) - (0.11/0.59)(B - Y)
TVTV i l b ji l b j (2)(2)
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1.0 1.01.0 1.0 1.0
1.01.01.01.0
1.0 1.0 1.01.0
1.0
0.20
0.20
0.20
0.20
0 0
0 0
0 0 0
0 0
0 0
0 0
0 0
0 0
0.5
0.5
0.5
0.30 0.15 0.65 0.59
0.11 0.70 0.41 0.89
0.700.35 0.35
-0.59
-0.11
-0.70
-0.59
0.11
-0.30 -0.15 -0.15
0.41
-0.11
0.30
-0.41
0.11
-0.30 -0.15 -0.15 -0.59
0.890.30
0.59
-0.89
W h i t e
G r a y
S a t u r a t e d
r e d
( v e r y b r i
S a t u r a t e d
r e d
( l e s s b r i
D e s a t u r a t e d r e d
S a t u r a t e d g
r e e n
S a t u r a t e d b l u e
S a t u r a t e d c y a n
S a t u r a t e d m
a g e n t a
S a t u r a t e d y
e l l o w
g
h t )
g h
t )
TVTV signal bojesignal boje(2)(2)
R
G
B
Y
R-Y
G-Y
B-Y
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NTSC signalNTSC signal
NTSC norme
I = 0.877 (R – Y) cos 33 – 0.493 (B – Y) sin 33
Q = 0.877 (R – Y) sin 33 + 0.493 (B – Y) cos 33
I Širina pojasa: 1.5 Mhz
Q Širina pojasa: 0.5 Mhz
Signale boje označavamo, (I,Q), (u,v) ili (R-Y, B-Y) ovisno o normama
B j i i li
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BojeBoje ii uu--v signalv signalii
0.1 0.2 0.3 0.4 0.5 0.6 0.7
-0.1-0.2-0.3-0.4-0.5-0.6-0.7
0.1
0.2
0.3
0.4
0.5
0.6
0.7
-0.1
-0.2
-0.3-0.4
-0.5
-0.6
-0.7
Magenta
61°
Blue
347°
Cyan
283°
Green
241°
Yellow
167°
Red
103°
U0.493 (B-Y)
V0.877 (R-Y)
Hue
saturation
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PrijenosPrijenos signala bojesignala boje -- NTSCNTSC
+90
DSBmodulator
nosilac boje +
Signal boje
I
Q
S(t) = I cos(ωst+33) + Q sin(ωst+33)
S(t)
DSB
modulator
3.58 Mhz
K kiK t ki i li l BVPSBVPS
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KromatskiKromatski signalsignal BVPSBVPS
1.00.89
0.70
0.59
0.410.30
0.11
0.0
W h i t e
C y a n
G r e e n
M a g e n t a
R e d
B l u e
B l a c k
Burst
10 ± 1 perioda
0 . 9 0
0 . 9 0
0 . 7 6
0 . 7 6
0 . 8 3
0 . 8 3
0 . 8 3
0 . 8 3
0 . 7 6
0 . 7 6
0 . 9 0
0 . 9 0
Luminantni signal
Kromatski signal
Y e l l o w
K it iKompo itni id i lideo signal BVPSBVPS
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KompozitniKompozitni video signalvideo signal BVPSBVPS
0 . 9 0
0 . 9
0
0 . 7 6
0 . 7 6
0 . 8 3
0 . 8 3
0 . 9 0
0 . 9
0
0 . 8 3
0 . 8 3
0 . 7 6
0 . 7 6
0
1.0
0.2
0.4
0.6
0.8
1.2
1.4
-0.2
-0.4-0.33
1.33
100 %
75%
20 %
0
C a r r i e r
a m p l i t u d e
RazineRazine kkompoompozitnogzitnog videovideo
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RazineRazine kkompoompozitnogzitnog videovideo
signalsignalaa
0 . 4 4
0 . 4 4
0 . 6 3
0 . 6 3
0 . 5
9
0 . 5 9
0 . 4 4
0 . 4 4
0 . 5 9
0 . 5 9
0 . 6 3
0 . 6 3
0
1.0
0.2
0.4
0.6
0.8
1.2
1.4
-0.2
-0.4-0.33
1.33
100 %
75 %
20 %
0
C a r r i e r a m p l i t u d e Black razina
Y e l l o w
W h i t e
C y a n C
y a n
M a g e
n t a
R e d
B l u e B
l a c k
White level
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Spektar BVPS signalaSpektar BVPS signala
0 1 2 3 4 5
Y
f (MHz)
0 1 2 3 4 5
0 1 2 3 4 5
0 1 2 3 4 5
4. 43 (nosioc boje - PAL)3.58 (nosioc boje – NTSC)
Širina pojasa (I,Q) ili (u,v) signala
Širina pojasa (I,Q) ili (u,v) signala
u
f (MHz)
v
f (MHz)
Kompozitni signal
f (MHz)
PALPAL s tustav (1)(1)
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PAL sPAL sustavustav (1)(1)
0.493 (B-Y)
0.877 (R-Y)
0.493 (B-Y)
-0.877 (R-Y)
Linija n
Linija n+1
φ
- φ
R – Y mijenja fazu izmjeničnolinijski i ispravlja faznupogrešku.
S(t) = (B-Y)sin(ωst) + (R-Y)cos(ωst)-
PAL sPAL s staustav (2)(2)
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PAL sPAL sustavustav (2)(2)
B-Y
R-Y
E n
E n+1
Odašiljač
B-Y
R-Y
E n
E n+1
Cn+1
C n
Prijamnik
ϕ
n+1C '
ϕ
UzorkovanjeUzorkovanje TV signalTV signalaa
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● Uzorkovanje po komponentama
Primjena: multimedia, digital TV
● Uzorkovanje BVPS
Primjena: TV prijamnik
kvaliteta slike
redukcija treperenja
UzorkovanjeUzorkovanje TV signalTV signalaa
U k j k tU k j k t
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Uzorkovanje komponenataUzorkovanje komponenata
ITU - 601 CIF QCIF
Uzorkovanje signala Y, u, v Y, u, v Y, u, v
Frekvencija uzorkova. Mhz. (Y) 13.5 - (u,v) 6.75 (Y) 6.75 - (u,v) 3.375 (Y) 6.75 - (u,v) 3.375
Struktura uzorkovanja orthogonal 1:1 orthogonal 1:1 orthogonal 1:1
Pixels / image (Y): 720 x 576 (Y): 352 x 288 (Y): 176 x 144
(u,v): 360 x 288 (u,v): 176 x 144 (u,v): 88 x 72
Bits/pixel 8 8 8