saa7105e NXP Semiconductors, saa7105e Datasheet - Page 60

• Manufacturer Part Number: saa7105e
• Description: Digital Video Encoder
• Manufacturer: NXP Semiconductors

Philips Semiconductors
11.1
Time t
and insert it into the CVBS and VBS output signal, such
that it appears at t
(NTSC) after the leading edge of the horizontal
synchronization pulse.
Time t
source that is gated by TTXRQ_XCLKO2 in order to
deliver TTX data. This delay is programmable by register
TTXHD. For every active HIGH state at output pin
TTXRQ_XCLKO2, a new teletext bit must be provided by
the source.
Since the beginning of the pulses representing the TTXRQ
signal and the delay between the rising edge of TTXRQ
and valid teletext input data are fully programmable
(TTXHS and TTXHD), the TTX data is always inserted at
the correct position after the leading edge of the outgoing
horizontal synchronization pulse.
2004 Mar 04
handbook, full pagewidth
Digital video encoder
CVBS/Y
TTX_SRES
TTXRQ_XCLKO2
FD
PD
Teletext timing
is the time needed to interpolate input data TTX
is the pipeline delay time introduced by the
TTX
text bit #:
= 9.78 s (PAL) or t
t PD
t TTX
1
2
t FD
3
4
TTX
5
= 10.5 s
6
Fig.14 Teletext timing.
7
8
9 10 11 12 13 14
60
Time t
TTX data; it has a constant length that allows insertion of
360 teletext bits at a text data rate of 6.9375 Mbits/s (PAL),
296 teletext bits at a text data rate of 5.7272 Mbits/s (world
standard TTX) or 288 teletext bits at a text data rate of
5.7272 Mbits/s (NABTS). The insertion window is not
opened if the control bit TTXEN is zero.
Using appropriate programming, all suitable lines of the
odd field (TTXOVS and TTXOVE) plus all suitable lines of
the even field (TTXEVS and TTXEVE) can be used for
teletext insertion.
It is essential to note that the two pins used for teletext
insertion must be configured for this purpose by the
correct I
i(TTXW)
2
t i(TTXW)
C-bus register settings.
is the internally used insertion window for
15
SAA7104E; SAA7105E
16 17 18 19 20 21 22 23
Product specification
MHB891
24