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TW9910 Schematic ( PDF Datasheet ) - Techwell

Teilenummer TW9910
Beschreibung Low Power NTSC/PAL/SECAM Video Decoder
Hersteller Techwell
Logo Techwell Logo 




Gesamt 70 Seiten
TW9910 Datasheet, Funktion
Techwell, Inc.
www.datasheet4u.com
TW9910 – Low Power NTSC/PAL/SECAM
Video Decoder with VBI Slicer
Data Sheet
Techwell Confidential. Information may change without notice.
Disclaimer
This document provides technical information for the user. Techwell, Inc. reserves the right to modify the
information in this document as necessary. The customer should make sure that they have the most recent data
sheet version. Techwell, Inc. holds no responsibility for any errors that may appear in this document. Customers
should take appropriate action to ensure their use of the products does not infringe upon any patents. Techwell,
Inc. respects valid patent rights of third parties and does not infringe upon or assist others to infringe upon such
rights.
TECHWELL, INC.
1
REV. A
09/21/2006






TW9910 Datasheet, Funktion
TW9910
Low Power NTSC/PAL/SECAM
Video Decoder with VBI Slicer
TW9910 employs high quality 4-H adaptive comb filter to reduce artifacts like hanging dots and
crawling dots. Due to the line buffer used in the comb filter, there is always two lines processing delay
in the output images no matter what standard or filter option is chosen.
www.datasheet4u.com
Color demodulation
The color demodulation of NTSC and PAL signal is done by first quadrature down mixing and then low-
pass filtering. The low-pass filter characteristic can be selected for optimized transient color
performance. For the PAL system, the PAL ID or the burst phase switching is identified to aid the PAL
color demodulation.
The SECAM decoding process consists of FM demodulator and de-emphasis filtering. During the FM
demodulation, the chroma carrier frequency is identified and used to control the SECAM color
demodulation.
The sub-carrier signal for use in the color demodulator is generated by direct digital synthesis PLL that
locks onto the input sub-carrier reference (color burst). This arrangement allows any sub-standard of
NTSC and PAL to be demodulated easily with single crystal frequency.
Automatic Chroma Gain Control
The Automatic Chroma Gain Control (ACC) compensates for reduced amplitudes caused by high-
frequency loss in video signal. The range of ACC control is –6db to +26db.
Color Killer
For low color amplitude signals, black and white video, or very noisy signals, the color will be “killed”.
The color killer uses the burst amplitude measurement as well as sub-carrier PLL status to switch-off
the color.
Automatic standard detection
The TW9910 has build-in automatic standard discrimination circuitry. The circuit uses burst-phase,
burst-frequency and frame rate to identify NTSC, PAL or SECAM color signals. The standards that can
be identified are NTSC (M), NTSC (4.43), PAL (B, D, G, H, I), PAL (M), PAL (N), PAL (60) and SECAM
(M). Each standard can be included or excluded in the standard recognition process by software
control. The identified standard is indicated by the Standard Selection (SDT) register. Automatic
standard detection can be overridden by software controlled standard selection.
TW9910 supports all common video formats as shown in Table 1. The video decoder needs to be
programmed appropriately for each of the composite video input formats.
TECHWELL, INC.
6
REV. A
09/21/2006

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TW9910 pdf, datenblatt
TW9910
Low Power NTSC/PAL/SECAM
Video Decoder with VBI Slicer
VBI Data Processing
www.datasheet4u.comRaw VBI data output
TW9910 supports raw VBI data output. Raw VBI data output has the same vertical line delay timing as
video output. Horizontal output timing is also programmable by VBIDELAY register. Raw VBI data is
generated during HACTIVE active period (from SAV to EAV) as Video data output. Total pixel number
of raw VBI data per line is twice as many as HACTIVE register value. If VBI EN register is set to “1”, all
vertical blanking output while VACTIVE is inactive will be raw VBI data output. If VVBI registers are set
to more than “1”, the VVBI number lines from top video active lines will also be raw VBI data output
lines.
VBI Data Slicer
The following VBI standards are supported by VBI Data slicer. The VBI Data slicing is controlled by the
registers LCTL6 to LCTL26. Registers LCTL6 to LCTL26 are controlling the slicing process itself.
LCTL6 to LCTL26 defines the Data Type to be decoded. The Data Type can be specified on a line by
line basis for line6 to line26 and for even and odd field depending on the detected TV system standard.
The setting for LCTL26 is valid for the rest of the corresponding field. Normally no text data 0H (video
data) should be selected to render the VBI Data slicer inactive during active video. LCTRL26 is useful
for Full-Field Teletext mode in the case of NABTS.
NABTS is 525 Teletext-C. Japan’s MOJI is 525 Teletext-D. Didon Antiope is 625 Teletext-A. VBI Data
slicer supports up to Physical layer, Link layer in ITU-R BT.653-2. Japan’s EIAJ CPR-1204 shown as
525 WSS has the same physical layer protocol as that of CGMS.
The sliced VBI data is embedded in the ITU-R BT.656 output stream, using the intervals between the
End of Active Video (EAV) and the Start of Active Vide(SAV) codes of each line and formatted
according to ITU-R BT.1364 Ancillary data packet Type 2.
Table 5. VBI Standard.
STANDARD TYPE TV Systems
(lines/freq)
625 Teletext-B
625/50
525 Teletext-B
525/60
625 Teletext-C
625/50
525 Teletext-C
525/60
625 Teletext-D
625/50
525 Teletext-D
525/60
625 CC
625/50
525 CC
525/60
625 WSS
626/50
525 WSS(CGMS) 525/60
625 VITC
625/50
525 VITC
525/60
Gemstar 2x
525/60
Gemstar 1x
525/60
VPS
625/50
625 Teletext-A
625/50
Bit Rate
(Mbits/s)
6.9375
5.727272
5.734375
5.727272
5.6427875
5.727272
0.500
0.503
5
0.447443
1.8125
1.7898
1.007
0.503
5
6.203125
Modulation Data Type
NRZ
NRZ
NRZ
NRZ
NRZ
NRZ
NRZ
NRZ
Bi-phase
NRZ
NRZ
NRZ
NRZ
NRZ
Bi-phase
NRZ
1H
1H
2H
2H
3H
3H
4H
4H
5H
5H
6H
6H
7H
8H
9H
AH
TECHWELL, INC.
12
REV. A
09/21/2006

12 Page





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