参数资料
型号: TDA9178N
厂商: NXP SEMICONDUCTORS
元件分类: 消费家电
英文描述: SPECIALTY CONSUMER CIRCUIT, PDIP24
封装: 0.400 INCH, PLASTIC, SOT-234, SDIP-24
文件页数: 37/39页
文件大小: 302K
代理商: TDA9178N
1999 Sep 24
7
Philips Semiconductors
Preliminary specication
YUV one chip picture improvement based on luminance
vector-, colour vector- and spectral processor
TDA9178
The maximum and minimum gain of each segment is
limited. Apart from the adaptive white-point stretching the
black and white references are not affected by the
non-linear processing. The amount of non-linearity can be
controlled by the I2C-bus non-linearity DAC:
bits NL5 to NL0.
VARIABLE GAMMA
On top of the histogram conversion a variable gamma
function is applied for an alternative brightness control, or
for factory adjustment. It is intended as an alternative for
the DC-offset of the classic brightness user control.
It maintains the black and white references. The gamma
ranges from 0.5 to 1.5. The gamma can be set by the
I2C-bus variable gamma DAC: bits VG5 to VG0.
CUE FLASH
In the present TV environment there is a lot of measured
information like ambient light and noise. This information
can be used to make an update of settings of the several
algorithms after a picture has changed. The cue flash
signal detects when a picture changes significantly. When
the picture content has changed, the I2C-bus bit CF is set
to logic 1 in the status register. After reading the status
register, bit CF is reset to logic 0. On the output pin CF the
cue flash information is present (active LOW) for only one
line in the vertical retrace part. This pin is configured as an
open drain output and therefore should be pulled up to the
5 V supply.
Spectral processor
In the spectral processor the luminance transfer is
controlled by smart peaking, colour dependent sharpness
and luminance transient improvement, defined by the
sharpness improvement processor. The colour transfer is
controlled by a colour transient improvement circuit; an
additional output is available to provide a SCAVEM circuit.
ADJUSTABLE CHROMINANCE DELAY
The colour vector processor drives a delay line for
correcting delay errors between the luminance input signal
and the chrominance input signals (U and V).
The chrominance delay can be adjusted in 6 steps of
12 ns (1fH) or 6 ns (2fH) by the I2C-bus bits CD2 to CD0.
SHARPNESS IMPROVEMENT PROCESSOR
The sharpness improvement processor increases the
slope of large luminance transients of vertical objects and
enhances transients of details in natural scenes by contour
correction.
It comprises three main processing units: the step
improvement processor, the contour processor and the
smart sharpness controller.
Transient improvement processor
The step improvement processor (see Fig.11) comprises
two main functions:
MINMAX generator
MINMAX fader.
The MINMAX generator utilizes all taps of an embedded
luminance delay line to calculate the minimum and
maximum envelope of all signals momentarily stored in the
delay line. The MINMAX fader chooses between the
minimum and maximum envelopes, depending on the
polarity of a decision signal derived from the contour
processor. Figures 12, 13 and 14 show some waveforms
of the step improvement processor and illustrate that fast
transients result with this algorithm. The MINMAX
generator also outputs a signal that represents the
momentary envelope of the luminance input signal.
This envelope information is used by the smart sharpness
controller.
Line width control (also called aperture control) can be
performed by I2C-bus line width DAC: bits LW5 to LW0.
This control can be used to compensate for horizontal
geometry errors caused by the gamma, for blooming of the
spot of the CRT, or for compensating SCAVEM.
Contour processor
The contour processor comprises two contour generators
with different frequency characteristics. The contour
generator generates a second-order derivative of the
incoming luminance signal which is supplied to the smart
sharpness controller. In the smart sharpness controller,
this signal is added to the properly delayed original
luminance input signal, making up the peaking signal for
detail enhancement. The peaking path features a low
peaking frequency of 2 MHz (at 1fH), or a high peaking
frequency of 3 MHz (at 1fH), selectable by I2C-bus
bit CFS.
The contour generators utilize three taps of the embedded
luminance delay line. Figure 15 illustrates the normalized
frequency transfer of the filter.
相关PDF资料
PDF描述
TDA9178T/N1 SPECIALTY CONSUMER CIRCUIT, PDSO24
TDA9178/N1,112 SPECIALTY CONSUMER CIRCUIT, PDIP24
TA8615N SPECIALTY CONSUMER CIRCUIT, PDIP30
TEA5711N AM/FM, AUDIO SINGLE CHIP RECEIVER, PDIP32
TDA6403AM-T 2-BAND, VIDEO TUNER, PDSO28
相关代理商/技术参数
参数描述
TDA9178T 制造商:PHILIPS 制造商全称:NXP Semiconductors 功能描述:YUV one chip picture improvement based on luminance vector-, colour vector- and spectral processor
TDA9181 制造商:PHILIPS 制造商全称:NXP Semiconductors 功能描述:Integrated multistandard comb filter
TDA9181P 制造商:PHILIPS 制造商全称:NXP Semiconductors 功能描述:Integrated multistandard comb filter
TDA9181T 制造商:PHILIPS 制造商全称:NXP Semiconductors 功能描述:Integrated multistandard comb filter
TDA9183 制造商:PHILIPS 制造商全称:NXP Semiconductors 功能描述:Integrated NTSC comb filter