UPD64084 datasheet(21/66 Pages) NEC

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µµµµ PD64084

Data Sheet S16021EJ2V0DS

YNR/CNR BLOCK

This block performs frame recursive YNR and CNR. It is used in the YCS+ mode.

Figure 7-1. YNR/CNR Block Diagram

∆Y

∆C

Frame

Memory

Y signal input

C signal input

Y signal output

C signal output

CNR

nonlinear

filter

YNR

nonlinear

filter

Killer signal detected

Current C

Current Y

Substraction of noise component

Previous frame Y

Previous frame C

YNR/CNR stop signal

Frame

difference

Frame

difference

∆Y'

∆C'

Noise

component

Noise

component

Delay

Demodulation

Modulation

+α

526H

+α

526H

LINE

KIL

YNRINV

YNRLIM

YNRK

CNRINV

CNRLIM

CNRK

Nonstandard

signal detection

Killer detection

7.1

YNR/CNR Processing

The frame difference (

∆Y) signal is generated by subtracting the previous frame Y signal from the current frame Y

signal. The noise component

∆Y' signal is extracted by eliminating the motion component of the ∆Y signal at the

nonlinear filter. Noise components are reduced by subtracting the noise component

∆Y' signal from the current frame Y

signal. At the same time, the Y signal submitted to noise reduction is delayed by a frame to be used to generate

∆Y for

the next frame. This way the frame recursive YNR is configured. Much the same processing is performed for the C

signal to reduce noise components.

7.2

Nonlinear Filter

The

∆Y' and ∆C' noise components are extracted from ∆Y and ∆C. ∆Y and ∆C contain inter-frame motion

components and noise components. Subtracting

∆Y and ∆C from the current frame Y and C signals causes inter-frame

motion components to remain in the output picture. To solve this problem, a nonlinear filter that passes only low-

amplitude signals is used; generally, motion components have a large amplitude, while noise components have a small

amplitude. How nonlinear the filter is to be is specified using YNRK, YNRLIM, YNRINV, CNRK, CNRLIM, and CNRINV

on the serial bus.

7.3

YNR/CNR Operation Stop

If the nonstandard signal detection circuit detects a vertical nonstandard signal or frame sync nonstandard signal, or

the LINE pin is at a high level, the killer detection circuit detects a color killer signal, or the KIL pin is at a high level,

YNR and CNR operations are stopped.

UPD64084 Datasheet(PDF) 21 Page - NEC

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