Service manual

CONFIDENTIAL – DO NOT COPY
Page 8-22
File No. SG-0176
The carrier frequency offset and symbol timing offset are both estimated and compensated
by a fully digital synchronizer . The synchronizer also controls the rate conversion in the
digital re-sampling device by estimating the sampling frequency offset . All synchronization in
MT5111 are integrated in digital circuits , no external VCXO is required.
The equalizer is adopted to cancel the effect of multi-path fading channel during signal
propagation in the air . The equalizer is not only capable of acquiring correct coefficients
combination by specified adaptive algorithms , but also programmable to different
configurations for various channel conditions.
The following FEC decoder corrects most of the errors by the concatenation of TCM and
Reed-Solomon decoders . The on-chip error rate estimator can simultaneously monitor the
receiving qualities at the three stages: equalizer output , TCM decoder , and transport stream
packets . The chip finally outputs the decoded MPEG-2 packets in either the serial or parallel
transport stream format.
In addition to the demodulation of HDTV signal , MT5111 also provides the capability to
remove the NTSC co-channel interference.To achieve the best reception condition , an
antenna interface compliant with EIA/CEA-909 is designed to control the antenna
parameters.
MT5111 is designed with efficient mechanisms of power saving . When configured to enter
the sleep mode by the system host , it can immediately turn off almost all embedded
hardware except the on-chip controller to reduce the power consumption . Resuming form
sleep mode is also triggered by the system host . Upon returning to the operation mode , the
chip will try to re-acquire the DTV signal automatically.
MT5111 Key Features:
1 . ATSC compliant 8-VSB demodulator
2 . Accepts dirtect IF (44 MHZ or 43.75 MHZ) and low IF (5.38 MHZ)
3 . Differential IF input with programmable input signal level : 0.5 Vpp to 2 Vpp
4 . NTSC interference rejection capability
5 . Compensate echo up to –5 to +47 us range
6 . On-chip 10-bit ADC for HDTV demodulator
7 . On-chip programmable gain amplifier