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TV Broadcast Demodulator IC Supports the
Japanese-Market Analog, Terrestrial Digital, and
Digital Satellite Broadcast Standards in a Single Chip
CXD2811GG
In addition to demodulation of the broadcast satellite and terrestrial digital broadcasts used in the
Japanese market, the CXD2811GG also provides both video detection and audio multiplex decoding, as
well as ghost reduction, for Japanese analog terrestrial broadcasts. It additionally provides waveform
adjustment functions for composite video signals and can easily implement the picture quality
adjustments required to match the characteristics of LCD panels or other displays.
An ultraminiature, thin-form tuner can be implemented using a chip set consisting of the CXD2811GG,
the CXA3746ER (terrestrial broadcast silicon tuner), and the CXA3775ER (BS/CS silicon tuner). |
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CXD2811GG |
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■ Excellent multipath performance
■ Fast synchronization acquisition
■ Built-in video detection and audio
multiplex decoding for analog
broadcasts
■ Ghost reduction circuit
■ Control functions for Sony silicon
tuner ICs |
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 Improved Reception Performance
for Terrestrial Digital Broadcasts |
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As terrestrial digital broadcasting expands to
cover all of Japan, and broadcast repeater
facilities are installed to handle areas with
difficult reception, resistance to multipath
interference will become an even more serious
issue for TV sets.
A year after Sony developed the first terrestrial
digital (ISDB-T) demodulation IC, the
CXD2807GG, while we had been confident
about the multipath characteristics, we refined
the transmission path inference algorithm and
improved the multipath characteristics both
inside and outside the guard interval even
further in the CXD2811GG, which we are
introducing here. Furthermore, we improved
the required C/N for the AWGN (additive white gaussian noise) to improve the weak
field reception characteristics. |
| High-Speed Synchronization
Acquisition for Terrestrial Digital |
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Some amount of time is required for the image
to appear when switching channels during
terrestrial digital broadcast reception. In the
CXD2811GG, we aimed to speed up
synchronization acquisition when switching
channels and achieved a time of merely 300 ms
from the channel switching command until the
transport stream is output. This contributes to a
smooth response when switching channels. |
Digital Signal Processing for
Analog Broadcasts
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Video signal detection and audio multiplex
decoding ICs that use analog signal processing
are used in conventional TV sets, and both
adjustments to match characteristics and
adjustments to handle temperature variations
are required. In the CXD2811GG, digital signal
processing is used for both video signal
detection and audio processing. This means
that there are no temperature variations and
no sample-to-sample IC variations and as a
result no characteristics adjustments are
required. |
| Forms an Optical Chipset with
Sony Silicon Tuner ICs |
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While it goes without saying that the
CXD2811GG supports a normal IF
(intermediate frequency: 58 MHz), which is the
output of a conventional can tuner, it also
supports low IF (4 MHz), which is the output
from Sony silicon tuner ICs such as the
CXA3746ER. Also, the CXD2811GG includes
software that optimizes high-frequency
reception performance and the AGC required
by the CXA3746ER. Since simple commands
from the TV set microcomputer suffice, the
application software verification period can
be reduced.
* The CXA3746ER and CXA3775ER are also
introduced in this issue of CX-NEWS in articles
that are available on this web site. |
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•••• Mr. Ono ••••
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During this development effort, at the same
time as hoping that these TV silicon tuner
and digital signal processing analog TV
reception products could change the way
TV sets are made, we also found it an
extremely challenging project. We are very
pleased that, thanks to the cooperation of
many people, we were able to complete
this development effort. |
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See
all articles with figures and tables.  |
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Vol.52 |
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