SN28837

1/2-INCH PAL TIMER

SOCS031B – JULY 1991

7

POST OFFICE BOX 655303

BF

Vertical

Scale

ABIN

GT1/SH3

SH1,GT3/SH2,

GT2

S1,S2,S3

HGATE

CBLK

1262

1265

1260

1254

1255

1270

1278

1286

1294

1302

1310 1862

1870

1878

1886

1894

1902

1910

1918

1926

LSW

1875

1924

1925

1872

1298

1248

1248

1250

1300

1875

1248

1276

1872

1900

1937

1245

1312

1870

1314

1939

1314

1867

1248

1872

1298

1924

1276

1250

1874

1900

VGATE

VD2

BCP2

BCP1

CP2

CP1

SF1

F1

IDP

SCBLK

VD

CSYNC

1243

1242

1256

1874

1890

1875

1250

1892

1910

1890

1885

1880

1875

1925

1250

1250

1250

1248

1268

1872

1892

1875

1875

1890

1265

1268

1268

1286

1286

1300

1300

1892

1910

1925

EQ

VS

EQ

EQ

VS

EQ

1246

1238

2H

4th Field

1st Field

1875

Always Continuous

PS, T

GT

PI

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 3. Vertical Timing (First and Fourth Fields)