TDA4688 Datasheet, PDF (17/24 Pages) NXP Semiconductors – Video processor with automatic cut-off control

Philips Semiconductors
Video processor with automatic cut-off control
Product specification
TDA4688
Table 3 Demodulator axes and amplification factors
PARAMETER
(B − Y)* demodulator axis
(R − Y)* demodulator axis
(G − Y)* demodulator axis
(R − Y)* amplification factor
(B − Y)* amplification factor
(G − Y)* amplification factor
NTSC
0°
95°
240°
1.59
2.03
0.606
PAL
0°
90°
236°
1.14
2.03
0.698
Table 4 PAL/SECAM and NTSC matrix; note 1
MATRIX
PAL/SECAM
NTSC
NMEN
0
1
Note
1. PAL/SECAM signals are matrixed by the equation: V_{G − Y} = −0.51V_{R − Y} − 0.19V_{B − Y}
NTSC signals are matrixed by the equations (hue phase shift of −2 degrees):
V_{R − Y*} = 1.39V_{R − Y} − 0.07V_{B − Y}; V_{G − Y*} = −0.46V_{R − Y} − 0.15V_{B − Y}; V_{B − Y*} = V_{B − Y}
In the matrix equations: V_{R − Y} and V_{B − Y} are conventional PAL demodulation axes and amplitudes at the output of
the NTSC demodulator. V_{G − Y*}, V_{R − Y*} and V_{B − Y*} are the NTSC modified colour difference signals; this is equivalent
to the demodulator axes and amplification factors shown in Table 3.
handbook, full pagewidth
(1)
(2)
cut-off measurement line
for red signal
(1) Maximum brightness.
(2) Nominal brightness.
Fig.6 Cut-off measurement pulse.
MHA697
ultra-black
1997 Jun 23
17