SDA9288X Datasheet, PDF (14/46 Pages) Siemens Semiconductor Group – Single Chip PIP System

SDA 9288X
2.3 PIP Field Memory
The on-chip memory stores one decimated field of the inset picture. Its capacity is
169 812 bits. The picture size depends on the horizontal and vertical decimation factors.
Horizontal Decimation
Y
3:1
212
4:1
160
PIP PIXELS per Line
(B-Y)
(R-Y)
53
53
40
40
Vertical Decimation
3:1
3:1
4:1
4:1
Line Standard
625
525
625
525
PIP Lines
88
76
66
57
In field mode display just every second inset field is written into the memory, in frame
mode display the memory is continuously written. Data are written with the lower inset
clock frequency depending on the horizontal decimation factor (4.5 MHz or 3.375 MHz).
Normally the read frequency is 13.5 MHz and 27 MHz for scan conversion systems.
For progressive scan conversion systems and HDTV displays a line doubling mode is
available (LINEDBL). Every line of the inset picture is read twice.
Memory writing can be stopped by program (FREEZE), a freeze picture display results
(one field).
Having no scan conversion and the same line numbers in inset and parent channel
(625 lines or 525 lines both) frame mode display is possible. The result is a higher
vertical and time resolution because of displaying every incoming field. For this purpose
the standards are internally analysed and activating of frame mode display is blocked
automatically when the described restrictions are not fulfilled.
As in the inset channel a field number detection is carried out for the parent channel.
Depending on the phase between inset and parent signals a correction of the display
raster for the read out data is performed by omitting or inserting lines when the read
address counter outruns the write address counter.
The display position of the inset picture is free programmable (POSHOR, POSVER).
The first possible picture position (without frame) is 54 clock periods (13.5 MHz or
27 MHz) after the horizontal and 4 lines after the vertical synchronization pulses. Starting
at this position the picture can be moved over the whole display area. Even
POP-positions (Picture Outside Picture) at 16:9 applications are possible.
Semiconductor Group
14
03.96