SDA9253 Datasheet, PDF (23/25 Pages) Siemens Semiconductor Group – 2.6 MBit Dynamic Sequential Access Memory for Television Applications (TV-SAM)

SDA 9253
Application Information
Digital Storage of a TV Field
As standard for digital TV systems, CCIR recommendation 601 defines a field of 288 lines with 720
pixels per line. The sampling frequency is 13.5 MHz with a resolution of 8 bit per pixel.
Information is stored in 3 different channels: one channel for luminance (Y), two channels for
chrominance (U and V).
The bandwidth ratio between the different channels is either Y:U:V = 4:1:1, 4:2:2 or 4:4:4 depending
on the coding method.
The following table shows the memory requirements for the field buffer and the number of memory
chips when the SDA 9253 and the SDA 9251 are used.
Table 1
Memory Requirements and Number of Memory Chips for a Digital TV-Field Buffer
Y:U:V
4:1:1
4:2:2
4:4:4
Clock Rate
13.5 MHz
2.37 Mbit
3.16 bit
4.75 bit
Number of Required
Memory Devices
1 SDA 9253
1 SDA 9253 +
1 SDA 9251
2 SDA 9253
Bus Width
12 bit
16 bit
24 bit
A typical application for the SDA 9253 is as field memory device in the Siemens MEGAVISION
system. The memory capacity of the SDA 9253 is 3 times that of SDA 9251 and therefore able to
substitute 3 SDA 9251. For a 4:1:1 sampling format there is need for 1 device in an application
without Line Flicker Reduction and 2 devices for an application with Line Flicker Reduction (see
figure).
Semiconductor Group
23
1998-01-30