TDA4685 datasheet(17/24 Pages) PHILIPS

17 / 24 page

1997 Jun 20

Philips Semiconductors

Product speciﬁcation

Video processor with automatic cut-off control

TDA4685

Table 3

Demodulator axes and ampliﬁcation factors

Table 4

PAL/SECAM and NTSC matrix; note 1

Note

1. PAL/SECAM signals are matrixed by the equation: VG − Y = −0.51VR − Y − 0.19VB − Y

NTSC signals are matrixed by the equations (hue phase shift of

−5 degrees):

VR − Y* = 1.57VR − Y − 0.41VB − Y; VG − Y* = −0.43VR − Y − 0.11VB − Y; VB − Y* =VB − Y

In the matrix equations: VR − Y and VB − Y are conventional PAL demodulation axes and amplitudes at the output of

the NTSC demodulator. VG − Y*, VR − Y* and VB − Y* are the NTSC modified colour difference signals; this is equivalent

to the demodulator axes and amplification factors shown in Table 3. VG − Y* = −0.27VR − Y* − 0.22VB − Y*.

PARAMETER

NTSC

PAL

− Y)* demodulator axis

115

− Y)* ampliﬁcation factor

1.97

1.14

− Y)* ampliﬁcation factor

2.03

MATRIX

NMEN

PAL/SECAM

NTSC

Fig.6 Cut-off measurement pulse.

(1) Maximum brightness.

(2) Nominal brightness.

handbook, full pagewidth

MHA697

cut-off measurement line

for red signal

ultra-black

(1)

(2)

TDA4685 Datasheet(PDF) 17 Page - NXP Semiconductors