Vizio VX42L HDTV10A Service Manual page 45

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.
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