TC90A49P/F

2001-03-06 9/17

9.

Color killer circuit

When the input video signal is a monochrome image, this circuit enables effective use of the luminance signal

information regardless of whether there is a burst signal. It does this by preventing the chroma signal output

from the comb filter from being subtracted from the luminance signal.

While the VBI signal is active it is better not to use the comb function. Setting the KILLER pin to High at this

time enables the use of character multiplex and other signals from the Y output unchanged.

10. RESET / TEST pin

voltage from Low to High triggers a reset. Normal use is Low.

11. I

2

C bus interface

Data transfer format

S

Slave address (8 bit)

A

DATA1

A

DATA2

A

DATA3

A

P

S : start condition

A : acknowledge

P : end condition

Slave address : B4 (HEX)

12. I

2

C bus control contents : When a reset signal is input, all the following bits are

zero-cleared.

MSB

bit7

bit6

bit5

bit4

bit3

bit2

bit1

LSB

bit0

DATA1

PDSOFF

CB

DATA2

DATA3

TRAP

CHTRAP

Fixed to 0

CBPF

Fixed to 0

Fixed to 0

Fixed to 0

ENHOFF

Mode 2 to Mode 0 : Select video signal format.

000 : Analog Through Mode 001 : M-PAL 010 : N-PAL 011 : PAL 100 : NTSC

When Analog Through mode is selected, input video signals are output to Yout and Cout unchanged. In

Analog Through mode, the delay time for output signals differs from those used for other modes. Therefore,

when changing modes to Analog Through mode, to decide the input signal format, provide some delay time

until an image is displayed.

There is a case where a 1 LSB error voltage at frequency fsc is multiplexed with the output signal. When

deciding the input signal format, to avoid an erroneous decision due to fsc leakage, be careful when setting

the decision sensitivity (killer sensitivity).

When the input signal is SECAM or 4.43 NTSC, select Analog Through mode. A separate BELL filter or a

BPF is required.