F1

TCS

SAND

0

4.67

8.5

1.5

33.5

64

continuous internal 1MHz clock

Phase lock off

All timings in

Phase lock

Figure 3 : Synchronization Timing

LSP

EP

BP

TCS

(interlaced)

TCS

(interlaced)

TCS

(non-interlaced)

0

0

0

2.33

4.66

32 34.33

32

27.33

59.33 64

64

64

All timings in

µs

621

(308)

622

(309)

623

(310)

624

(311)

625

(312)

12

345

6

309

310

311

312

313

314

(1)

315

(2)

316

(3)

317

(4)

318

(5)

319

(6)

308

309

310

311

312

1

2

3

4

5

6

The number positions indicate the end of lines.

The Teletext composite synchronization signal (TCS), whether interlacing is present or not, comprise

three components.

a) the line-synchronization pulses (LSP).

b) the equalization pulses (EP)

c) the frame-synchronization pulses (BP).

The timing reference is specified by the descending edge of the signal LSP, with a tolerance spread of

± 100ns.

Figure 4 : Composite Sync. Waveforms

STV5342

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