TDA9178T Philips Semiconductors, TDA9178T Datasheet - Page 2

• Manufacturer Part Number: TDA9178T
• Description: YUV one chip picture improvement based on luminance vector-/ colour vector- and spectral processor
• Manufacturer: Philips Semiconductors

Philips Semiconductors
FEATURES
GENERAL DESCRIPTION
The TDA9178 is a transparent analog video processor
with YUV input and output interfaces. It offers three main
functions: luminance vector processing, colour vector
processing and spectral processing. Beside these three
main functions, there are some additional functions.
In the luminance vector processor, the luminance transfer
function is controlled in a non-linear way by the
distribution, in 5 discrete histogram sections, of the
luminance values measured in a picture. As a result, the
contrast ratio of the most important parts of the scene will
be improved. Black restoration is available in the event of
a set-up in the luminance signal.
A variable gamma function, after the histogram
conversion, offers the possibilities of alternative brightness
control or factory adjustment of the picture tube.
1999 Sep 24
Picture content dependent non-linear Y, U and V
processing by luminance histogram analysis
Variable gamma control
Adaptive black and white stretch control
Skin tone correction
Green enhancement
Blue stretch
Luminance Transient Improvement (LTI)
Smart peaking for detail enhancement
Colour Transient Improvement (CTI)
SCAn VElocity Modulation (SCAVEM) output
Line Width Control (LWC)
Video Dependent Coring (VDC)
Colour Dependent Sharpness (CDS)
Noise measurement
Feature Mode (FM) detector
Cue Flash (CF) detector
Three additional pins for access to 6-bit ADC and
I
Adjustable chrominance delay
TV standard independent
1f
DEmonstration MOde (DEMO).
YUV one chip picture improvement based on luminance
vector-, colour vector- and spectral processor
2
I
2
C-bus
H
C-bus controlled
and 2f
H
2
The adaptive black stretch function of the TDA9178 offers
the possibility of having a larger ‘weight’ for the black parts
of the video signal; the white stretch function offers an
additional overall gain for increased light production.
To maintain a proper colour reproduction, the saturation of
the U- and V-colour difference signals is also controlled as
a function of the actual non-linearity in the luminance
channel.
In the colour vector processor, the dynamic skin tone
correction locally changes the hue of colours that match
skin tones to the correct hue. The green enhancement
circuit activates medium saturated green towards to more
saturated green. The blue stretch circuit can be activated
which shifts colours near white towards blue.
The spectral processor provides 1D luminance transient
improvement, luminance detail enhancement by smart
peaking and a 1 D colour transient improvement.
The TDA9178 can be used as a cost effective alternative
to (but also in combination with) scan velocity modulation.
In the spectral processor line width control (or aperture
control) can be user defined. The TDA9178 is capable of
adjusting the amount of coring according to the video level
with the video dependent coring. The TDA9178 is also
capable to give extra sharpness in the cases of saturated
red and magenta parts of the screen using the colour
dependent sharpness feature.
An embedded noise detector measures noise during the
field retrace in parts which are expected to be free from
video or text information. With the noise detector a variety
of ‘smart noise control’ architectures can be set up.
A feature mode detector is available for detecting signal
sources like VCR (in still picture mode) that re-insert the
levels of the retrace part. For this kind of signals the noise
measurement of the TDA9178 is not reliable.
An output signal (on the I
available that detects when the picture content has been
changed significantly, called cue flash.
An embedded 6-bit ADC can be used for interfacing three
analog low frequency voltage signals (e.g. ambient light
control or beam current voltage level) to the I
2
C-bus and on a separate pin) is
Preliminary specification
TDA9178
2
C-bus.