4

521 - 01 - 05

PAL/NTSC THRESHOLD ADJUST

To adjust the P/N threshold using a potentiometer, monitor the

OUT voltage at pin 2 of the GS9010A. Start with a composite

connect a PAL source to the input and record the voltage at pin

Gating of the HSYNC input is available on the SWF pin. This

gating is used with the GS9010A to improve immunity to

missing TRS detection during power-up or in noisy system

applications.

Capacitor values for the GS9010A should be used as indicated

in Figure 3.

These capacitors have been optimised to

produce correct system operation.

GS9010 REPLACEMENT NOTE:

To ensure proper operation of the GS9010A, the resistor

network connected between the GS9010A OUT (pin 2) and

be as per this data sheet (Figure 3). Replacing a GS9010 with

a GS9010A will require modification to these component

values.

RE-TIMED DATA

RECOVERED CLOCK

RVCO

1k2

1k2

100nF

120

Ω

THRESHOLD

ADJUST

SERIAL

DATA IN

2

1

13

8

HSYNC

20k

SWF

+

-

OSCILLATOR

COMPOSITE /

COMPONENT

DETECTOR

PAL/NTSC

÷ 4

5

14

LOOP

FILTER

6

16

+5V

MODULUS

CONTROL

ƒ/2

CARRIER

DETECT

GS9005A/GS9015A

GS9000B/GS9000S

GS9010A

SERIAL

DIGITAL

PLL

DIGITAL

VIDEO

DECODER

+

-

18k

25k

Ω

All resistors in ohms, all capacitors in microfarads unless otherwise stated.

Fig. 1

Automatic Tuning Sub System Block Diagram