參數(shù)資料
型號： SAA4979H
廠商： NXP SEMICONDUCTORS
元件分類： 消費家電
英文描述： Sample rate converter with embedded high quality dynamic noise reduction and expansion port
中文描述： SPECIALTY CONSUMER CIRCUIT, PQFP128
封裝： 28 X 28 X 3.40 MM, PLASTIC, QFP-128
文件頁數(shù)： 11/52頁
文件大?。?/td> 224K
代理商： SAA4979H
2002 May 28
11
Philips Semiconductors
Product specification
Sample rate converter with embedded high quality
dynamic noise reduction and expansion port
SAA4979H
7.1.4
D
YNAMIC NOISE REDUCTION
The main function of the noise reduction is shown in Fig.4.
It is divided into two signal paths for chrominance and
luminance. In principal two operating modes can be used,
the fixed and the adaptive mode. In both modes the
applied frequency range, in which the noise reduction
takes place, can be reduced or not reduced (control input:
unfiltered).
The noise reduction operates field recursive with an
averaging ratio (K factor) between fresh (new) and over
previousfieldsaveraged(old)luminanceandchrominance
values. Noise reduction can be activated by forcing the
NREN control bit to HIGH. If NREN is LOW the noise
reduction block is bridged via a data multiplexer.
In the fixed mode, the noise reduction produces a constant
weighted input averaging. Because of smearing effects
this mode should not be used for normal operation except
for K = 1. The fixed mode can be activated separately for
chrominance (control input: chromafix) and luminance
(control input: lumafix).
In the adaptive mode, the averaging ratio is based on the
absolute differences of the inputs of luminance and
chrominance respectively. If the absolute difference is low,
only a small part of the fresh data will be added. In cases
of high difference, much of the fresh data will be taken.
This occurs either in situations of movement or where a
significant vertical contrast is seen. The relationship
between the amount of movement and the K factor values
is defined in a look-up table where the steps can be
programmed (control input: Kstep).
It should be noted that recursion is done over fields, and
that pixel positions between the new and old fields always
have a vertical offset of one line. So averaging is not only
done in the dimension of time but also in the vertical
direction. Therefore averaging vertically on, for example, a
vertical black to white edge would produce a grey result.
The averaging in chrominance can optionally be slaved to
the luminance averaging (control input: Klumatochroma),
in that case chrominance differences are not taken into
account for the K factor setting of the chrominance signal
path.
The noise reduction scheme also decreases the
cross-colour patterns effectively if the adaptive noise
reduction for the averaging in chrominance is slaved to the
luminance averaging (control input: Klumatochroma). The
cross-colour pattern does not produce an increase of the
measured luminance difference, therefore this pattern will
be averaged over many fields.
相關(guān)PDF資料
PDF描述
SAA4981 Monolithic integrated 16 : 9 compressor
SAA4981T Monolithic integrated 16 : 9 compressor
SAA4993H Field and line rate converter with noise reduction
SAA4994H Field and line rate converter with noise reduction
SAA4998H Field and line rate converter with noise reduction and embedded memory
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
SAA4981 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Monolithic integrated 16 : 9 compressor
SAA4981T 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Monolithic integrated 16 : 9 compressor
SAA4990 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Progressive scan-Zoom and Noise reduction IC PROZONIC
SAA4990H 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Progressive scan-Zoom and Noise reduction IC PROZONIC
SAA4992 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Field and line rate converter with noise reduction
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。

采購需求

(若只采購一條型號，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進(jìn)入我的后臺，查看報價

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進(jìn)入我的后臺，查看報價

*型號 *數(shù)量 廠商 批號 封裝
添加更多采購

我的聯(lián)系方式

*
*
*