TDA8980 データシートの表示（PDF） - Philips Electronics
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TDA8980 Datasheet PDF : 36 Pages
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Philips Semiconductors
ATSC Digital Terrestrial TV
demodulator/decoder
Objective specification
TDA8961
GENERAL DESCRIPTION
The TDA8961 is an Advanced Television Systems
Committee (ATSC)-compliant demodulator and FEC
decoder for reception of 8-VSB modulated signals for
terrestrial and cable applications:
• Terrestrial: reception of 8-VSB modulated signals via
standard 6 MHz VHF/UHF terrestrial TV channels (TV
channels 2 to 69 in the United States).
• Cable: reception of 8-VSB modulated signals via
standard 6 MHz VHF/UHF cable TV channels.
An application using the TDA8961 and the TDA8980
NTSC/ATSC TV input processor for TV and Multi-Media is
shown in Fig.1. A tuner converts the incoming RF signal to
a fixed IF centered at 44 MHz. The output signal from the
tuner is filtered and fed to the TDA8980 which performs the
following functions:
• Decodes the analog NTSC signals: The audio signals
are digitized, using on-chip audio stereo A/D converters,
into an I2S-bus stream; the video information is digitized,
using on-chip video A/D converters, into an ITU656
stream.
• Down converts the incoming 6 MHz wide 8-VSB IF
signal to a low-IF signal centered at 4 MHz: The low-IF
signal is then digitized, using an on-chip 10-bit A/D
converter, and fed to the TDA8961 for further
processing. In this application, AGC is also managed by
the TDA8980 so that no other external components,
such as an operational amplifier loop integrator, are
required.
Although the TDA8980 has an internal 2-D comb filter,
external filters such as a 3-D comb filter and other picture
improvement devices can easily be connected. Sound can
be decoded using an external device such as the
TDA9851 I2C-bus controlled economic BTSC stereo
decoder. This IC has an internal switch allowing it to
process either analog NTSC IF or digital 8-VSB IF signals.
A 12 MHz clock signal is generated using a 12 MHz crystal
connected to the TDA8980. The TDA8961 also uses this
clock signal which is fed from the TDA8980 to pin XTALI of
the TDA8961.
handbook, full pagewidth
TUNER
I2C
NTSC
SAW
FILTER
FLAT
SAW
FILTER
TDA8980
TVIFIN
VCLK
D9 to D0
VSBIFIN
REF12M
VIFAGC
TUNERAGC
I2C X12MOUT X12MIN
TDA8961
ADCLK
ADIN9 to ADIN0
XTALI
AGCOUT
PDOVAL
PDOERR
PDO7 to PDO0
PDOSYNC
PDOCLK
MPEG-2
transport
stream
12 MHz
I2C PDI0 PDISYNC PDIVAL PDICLK PDIERR MGU085
I2C
master
serial MPEG-2 transport
stream input
Fig.1 Front-end design for a hybrid TV system using the TDA8980 and TDA8961.
2000 May 19
3
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