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For cable signal reception, the MT5112BD adopts the fully digital modules for timing and
carrier synchronization, with no external VCXO required. Specially designed carrier
synchronization module enables the MT5112BD passing the OpenCable ATP burst and
phase noise tests, while maintaining excellent reception performance under normal
reception conditions.
The MT5112BD also utilizes a powerful equalizer for performing channel equalization in
cable environments. The MT5112BD equipped with this powerful equalizer can easily
pass the SCTE channel tests and offer stable and excellent live signal receptions.
The following FEC decoder corrects most of the errors by the concatenation of the TCM
and Reed-Solomon decoders with an in-between de-interleaver. Specifically for the digital
cable TV reception, the MT5112BD first detects and aligns de-puncturing timing of the
received sequence before TCM decoding. Besides, two synchronization circuits are each
inserted before the de-interleaver and after the Reed-Solomon decoder to automatically
delineate the FEC frames and transport stream packets respectively. An on-chip error rate
estimator can simultaneously monitor the receiving qualities at the three stages: the
equalizer output, the TCM decoder, and the transport stream packets. At the last stage,
the MT5112BD incorporates a buffer to smooth out the uneven arrival time of transport
stream packets. The chip finally outputs the smoothed decoded MPEG-2 transport stream
packets in either the serial or parallel transport stream format.
In addition to the demodulation of HDTV signal, MT5112BD provides the capability to
remove narrow-band interference such as the co-channel NTSC signal and CW tones
which generally exists in broadcast environment.
To achieve the best reception, an antenna control interface compliant with EIA/CEA-909 is
equipped into the MT5112BD to configure the antenna parameters. Both the unidirectional
mode A and the bi-directional mode B operation schemes are supported.
Page 7-16
CONFIDENTIAL – DO NOT COPY
File No. SG-0212
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