SN28837

1/2-INCH PAL TIMER

SOCS031B – JULY 1991

8

POST OFFICE BOX 655303

2H

625

0

Vertical

Scale

0

0

2488

2492

2496 0

4

8

12 16

20 24 28 32

36 40 44 48 52

56 60 612 616 620 624

628

625

3rd Field

2nd Field

632 636 640 644 648 652 656 660 664 668 672 676

50

675

2496

16

620

640

15

625

18

36

50

625

642

660

675

18

36

642

660

0

15

2498

16

640

676

050

625

625

675

2498

48

622

674

2498

26

622

650

2493

2495

62 64

618 620

687 689

2492

64

617

689

CSYNC

CBLK

BF

VD

LSW

SCBLK

IDP

FI

SFI

CP1

CP2

BCP1

BCP2

VD2

VGATE

Always Continuous

HGATE

PI

GT

2498

48

622

674

PS,T

AB IN

0

26

624

624

650

0

26

624

650

S1,S2,S3

SH1, GT1/SH3,

GT3/SH2

GT2

EQ

EQ

VS

EQ

EQ

VS

NOTES: A. GPS is low and VD is fed back to GP.

B. When GPS is high, VGATE is always low.

C. 1 field = 312 1/2 horizontal lines = 625 vertical counts. 1 frame = 625 horizontal lines = 1250 vertical counts. Period of each count

of vertical counter = 32

µs.

Figure 4. Vertical Timing (Second and Third Fields)