June 1986

8

Philips Semiconductors

Product specification

PAL/NTSC/SECAM synchronization

processor for video recorders

TDA3755

Notes to the characteristics

1. Or not connected.

2. The sync separator input signal is shown in Fig.2.

3. The black level and the top sync level are detected internally and stored in capacitors at pin 2 and pin 3 respectively.

4. The vertical sync pulse output is disabled by mute.

5. In test picture mode the synthetic sync pulse is fed to output pin 1 and the vertical pulse consists of an uninterrupted

block pulse of 192

µs triggering at every transition of head pulse (HP) at pin 9. The timing of test picture and synthetic

sync pulse is shown in Fig.3.

7. The holding range and catching range are both determined by the resistor connected between pin 5 and pin 6.

8. The phase of the lower subcarrier is switched in accordance with the VHS standard. PNP emitter follower, internal

resistive load of 10 k

9. The output voltage at pin 5 is disabled during test picture mode.

10. The burst gating pulse is superimposed on an uninterrupted horizontal pulse. It is suppressed 16 times starting with

every transition of the head pulse at pin 9. If a vertical pulse is detected during that time the burst gating pulses are

additionally suppressed until line 12 and line 324 respectively. In any event the number of suppressed burst gating

pulses is even.

11. The timing of the upper part of the sandcastle pulse is determined by the components connected to pin 12 (Fig.4)

and is independent of supply voltage variations.

12. The fast phase correction pulses have to be in the burst gating reference pulse. For any HIGH to LOW transitions of

the correction pulse the phase is corrected by

−90° if the head pulse input is LOW and by +90° if the head pulse input

is HIGH.

13. Subcarrier phase switching is detailed in Table 1.

Subcarrier is 40,000

Table 1

Subcarrier phase switching

STILL

PAL

NTSC

PICTURE INPUT

HP = HIGH

HP = LOW

HP = HIGH

HP = LOW

HIGH

−90°−90°−90°−90°

not connected

0

°−90°+90°−90°

LOW

0

°

0

°+90°+90°