1

l Introduction

l Analog TV systems

l Progressive and interlaced systems

l Synchronism signals

l Composite signal

l Components signal

l NTSC and PAL systems

l Sampling of the TV signal

2

Real world0

Am

plitu

de

Electrical signal

Camera Transmitter

ReceiverTV screenVisual system

3

Sclera

Optic nerve

Blind spot

Aqueoushumor

Vitreous humor

LensCorneaIris

Fovea

Retina

Glare limit

Ada

ptat

ion

rang

e

Subj

ectiv

e br

ight

ness

Scotopicthreshold

Bb

Ba

Scotopic

Photopic

Log of intensity

0.5

1

2

4

8

1 1.5 2 3 4 6 8 1216 240.5

0.2

0.1

0.05

0.02

0.01

Sens

ibili

ty to

con

trast

Temporal frequency (Hz)

Spati

al fre

quen

cy (

cycle

s/deg

ree)

4

Number of lines per image:

Depends on desired vertical definition

Number of images per second:

No flicker > 50Motion sensation > 15

5

1 cycle

33.5 cyclesper image height

6

1 cycle

6.5 cyclesper image height

7

1 cycle

1.5 cyclesper image height

8

1 cycle

33.5 cyclesper image width

9

1 cycle6.5 cycles

per image width

10

1 cycle

1.5 cyclesper image width

11

+ =

13579

111315

2468

101214

Odd field Even field Complete image

1/60s 1/60s 1/30s

13

5

A

B

A

D

C

B

246

D

C

Odd lines Odd field flyback Even lines Even field flyback

Number of lines: 525Number of images: 30

Number of fields: 602 fields = 1 image

12

Horizontal scanning Horizontal flyback Vertical flyback

..1

3

5

7

9

11

13

15

17

19

2

4

6

8

10

12

14

16

18

C

D B.

A

.

13

100

75

50

25

0

Am

plitu

de %

White level

Blanking level

Maximum level

Video signal

Horizontal synchronism

Line N

14

even

odd

15

fh: Line frequency (15.750)

fv: Field frequency (60)

fv 2fhfh2fv

0f

f0 5 MHz

16

Microphone

TV camera

Audio Amplif.

FMmodulator

Sound carrier

RF Amplif.

Video Amplif.

Sync.generation

camaratime

base

Video adder

+ sync

AMmodulator

Video carrier

Video R.F.

Amplif.

VestigialLateral band

filter

+

17

0 1

1

0.5

0.5

Receive

r

Emitter

X

Y

Y=X1/2.8

Y=X2.8

18

Tuner FIAmplifier

Detector

GACDelayGAC

VideoAmplif.

Sounddetector

Sound Amplif.

Syncseparator

Sync. processing

Sync processing

Line oscilator

Fieldoscilator

LineoutputFieldoutput

Limiter Amplif.

19

+

RGB

Camera Bandwidth is 3 x 5 MHz = 15 Mhz

B - BlueG - GreenR - Red

20

CameraRGB

Bandwidth is 7 Mhz

Y - Luminance

Y = 0.30R + 0.59G + 0.11Bu = 0.495 (B – Y)v = 0.877 (R - Y)

5 MHz1 MHz1 Mhz

u = 0.495 (B – Y) v = 0.877 (R - Y)

21

Y + R - Y = RY + G - Y = GY + B - Y = B

CameraRGB

Bandwidth is 7 Mhz

Y = 0.30R + 0.59G + 0.11BR - YB - Y

5 MHz1 MHz1 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

ReceiverY

R - YB - Y

G - Y = -(0.3/0.59)(R - Y) - (0.11/0.59)(B - Y)

Screen

22

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

0.89 0.30 0.59

-0.89

Whi

te

Gra

y Sat

urat

ed re

d (v

ery

brig

ht)

Sat

urat

ed r

ed(le

ss b

right

)

Des

atur

ated

red

Sat

urat

ed g

reen

Sat

urat

ed b

lue

Sat

urat

ed c

yan

Sat

urat

ed m

agen

ta

Sat

urat

ed y

ello

w

R

G

B

Y

R-Y

G-Y

B-Y

23

NTSC defines

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 Bandwidth: 1.5 Mhz

Q Bandwidth: 0.5 Mhz

Note: Next slides will use, (I,Q), (u,v) or (R-Y, B-Y) indistinctlySignals are not exactly the same, but concepts are.

There is a weighting factor applied

24

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°

Green241°

Yellow167°

Red103°

U 0.493 (B-Y)

V 0.877 (R-Y)

Hue

saturation

25

+90

Amplitudemodulation

subcarrieroscilator

+CHROMINANCE

I

Q

S(t) = I cos(ωst+33) + Q sin(ωst+33)

S(t)

Amplitudemodulator

3.58 Mhz

26

1.00.89

0.700.59

0.410.30

0.11

0.0

Whi

te

Cya

n

Gre

en

Mag

enta

Red

Blu

e

Bla

ck

Burst 10 ± 1 cycles

0.90

0.90

0.76

0.76

0.83

0.83

0.83

0.83

0.76

0.76

0.90

0.90

Luminance signal

Chrominance signal

Yel

low

27

0.90

0.90

0.76

0.76

0.83

0.83

0.90

0.90

0.83

0.83

0.76

0.76

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

Car

rier

am

plitu

de

28

0.44

0.44

0.63

0.63

0.59

0.590.44

0.44

0.59

0.59

0.63

0.63

0

1.0

0.20.40.60.8

1.21.4

-0.2-0.4-0.33

1.33

100 %

75 %

20 %

0

Car

rier

am

plitu

de Black level

Yel

low

Whi

te

Cya

n

Cya

n

Mag

enta

Red

Blu

e

Bla

ck

White level

29

f (MHz)0 1 2 3 4 5

f (MHz)0 1 2 3 4 5

f (MHz)0 1 2 3 4 5

f (MHz)0 1 2 3 4 5

4. 43 (color subcarrier - PAL)3.58 (color subcarrier – NTSC)

u

v

Composite signal

Y

Bandwidth depends on (I,Q) or (u,v) signals

Bandwidth depends on (I,Q) or (u,v) signals

30

0.493 (B-Y)

0.877 (R-Y)

0.493 (B-Y)

-0.877 (R-Y)

Line n

Line n+1

φ

- φ

S(t) = (B-Y)sin(ωst) + (R-Y)cos(ωst)-

R – Y is switched each line to compensate for thephase errors (hue)

31

B-Y

R-Y

E n

E n+1

EMITTER

B-Y

R-Y

En

E n+1

Cn+1

C n

RECEIVER

ϕ

n+1C '

ϕ

32

l Component sampling

Applications: multimedia, Digital TV

l Composite signal sampling

Applications at the TV receiver

Image enhancement

Flicker reduction

33

ITU - 601 CIF QCIF

Sampled signals Y, u, v Y, u, v Y, u, v

Sampling frequency Mhz. (Y) 13.5 - (u,v) 6.75 (Y) 6.75 - (u,v) 3.375 (Y) 6.75 - (u,v) 3.375

Sampling structure 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