SDA9254-2 Infineon Technologies Corporation, SDA9254-2 Datasheet - Page 4

• Manufacturer Part Number: SDA9254-2
• Description: 2.6mb Dynamic Sequential Access Memory For Television Applications (tv-sam) With On-chip Noise Reduction Filter
• Manufacturer: Infineon Technologies Corporation

Figure 3
Block Diagram of the Noise Reduction Filtering
To avoid artefacts in moving parts of the picture a motion detector is implemented to control the filter
coefficient K according to detected changes between two adjacent fields. The motion detector
performs a low pass filtering of the field differences and builds the absolute values. The results
control the filter coefficient K by choosing one of 13 predefined values between 1/4 and 1. The
characteristic of this assignment influences the amount of noise reduction and is adjustable via the
CLASS-pins. The calculation of the filter coefficient is practised for each pixel of the field.
Adjustment of the Characteristic of the Noise Reduction Filter
CLASS2
x
x
0
1
x
These four possible adjustments put a wide field of different intensities of noise reduction at user’s
disposal.
The recursive filter also enables a reduction of cross color interference because the Motion Detector
exploits only luminance data.
Semiconductor Group
SDC0 ... 11
Video Input
Port B
Memory
CLASS
Luminance
Luminance
delayed
Input
CLASS1
0
0
1
1
1
12
12
3
Detector
DEMUX
DEMUX
8
8
Motion
CLASS0
0
1
0
0
1
8
8
Input Chrominance
delayed Chrominance
K
4
Amount of Noise Reduction
Low
Low-mid
Mid-high
High
Noise reduction off
Recursive
Filter
4
8
8
BLN
Clock and
Control
MUX
SCB
12
SDA 9254-2
1998-01-16
UEB10381
Memory
Port C