saa7105e-v1-g NXP Semiconductors, saa7105e-v1-g Datasheet - Page 66

• Manufacturer Part Number: saa7105e-v1-g
• Description: Digital Video Encoder
• Manufacturer: NXP Semiconductors

Philips Semiconductors
SAA7104E_SAA7105E_2
Product data sheet
Fig 15. Teletext timing
CVBS/Y
TTX_SRES
TTXRQ_XCLKO2
11.1 Teletext timing
text bit #:
Time t
VBS output signal, such that it appears at t
after the leading edge of the horizontal synchronization pulse.
Time t
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.
Time t
that allows insertion of 360 teletext bits at a text data rate of 6.9375 Mbit/s (PAL),
296 teletext bits at a text data rate of 5.7272 Mbit/s (world standard TTX) or 288 teletext
bits at a text data rate of 5.7272 Mbit/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
t
PD
t
TTX
1
FD
PD
i(TTXW)
is the time needed to interpolate input data TTX and insert it into the CVBS and
is the pipeline delay time introduced by the source that is gated by
2
t
FD
3
is the internally used insertion window for TTX data; it has a constant length
4
5
Rev. 02 — 23 December 2005
6
7
8
9 10 11 12 13 14
SAA7104E; SAA7105E
TTX
t
i(TTXW)
2
= 9.78 s (PAL) or t
C-bus register settings.
15
16 17 18 19 20 21 22 23
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
TTX
Digital video encoder
= 10.5 s (NTSC)
mhb891
24
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