TDA4780 Datasheet, PDF (14/44 Pages) NXP Semiconductors – RGB video processor with automatic cut-off control and gamma adjust

Philips Semiconductors
RGB video processor with automatic
cut-off control and gamma adjust
Preliminary specification
TDA4780
Note
1. Matrix coefficients should be tested by comparing RGB output signals with a reference RGB colour bar, which is fed
in at (RGB)₁ or (RGB)₂ inputs. In the event of NMEN = 1 (NTSC) at minimum saturation the Y output and RGB output
signals are not identical to the Y input signal. 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}
For demodulation axis see Fig.11.
In the matrix equations: V_{R − Y} and V_{B − Y} are conventional PAL demodulation axes and amplitudes at the output of
the demodulator. V_{R − Y*}, V_{G − Y*} and V_{B − Y*} are the NTSC-modified colour-difference signals.
handbook, full pagewidth
maximum brightness
nominal brightness
cut-off measurement line
for green signal
Fig.7 Cut-off measurement pulses.
ultra-black
MGE878
1997 Feb 06
14