FLLXT1000BA.C4QE000 Intel, FLLXT1000BA.C4QE000 Datasheet - Page 51

• Manufacturer Part Number: FLLXT1000BA.C4QE000
• Manufacturer: Intel

Specifications of FLLXT1000BA.C4QE000

• Lead Free Status / RoHS Status: Not Compliant

2.5.3.6
2.5.3.7
2.5.3.8
2.5.3.9
2.5.4
Datasheet
Document #: 249276
Revision #: 002
Rev. Date: 07/20/01
The adaptive filter coefficients are initially set during the training phase. They are continuously
adjusted (“adaptive equalization”) during operation through the decision-feedback loop.
Descrambler
The descrambler identifies each channel by its characteristic signature, removing the signature and
re-routing the channel internally. In this way, the receiver can correct for channel swaps and
polarity reversals. The descrambler uses the same base 33-bit LFSR used by the transmitter on the
other side of the link.
The descrambler automatically loads the seed value from the incoming stream of scrambled idle
symbols. The descrambler requires approximately 15 s to lock, normally accomplished during the
training phase.
Viterbi Decoder/Decision Feedback Equalizer (DFE)
The Viterbi decoder generates clean 4DPAM5 symbols from the output of the DSP. The Viterbi
decoder simultaneously looks at the received data over several baud periods. For each baud period,
it predicts whether the symbol received should be even or odd, and compares that to the actual
symbol received. The 4DPAM5 code is organized in such a way that a single level error on any
channel changes an even code to an odd one and vice versa. In this way, the Viterbi decoder can
detect single-level coding errors, effectively improving the signal-to-noise (SNR) ratio by a factor
of 6dB. When an error occurs, this information is quickly fed back into the equalizer to prevent
future errors.
4DPAM5 Decoder
The 4DPAM5 decoder generates 8B data from the output of the Viterbi decoder.
8B/10B Encoder
The 8B/10B encoder converts 8B data into 10B codes and is used when the MAC interface is
configured in TBI mode. (This function is not used when the MAC interface is configured for
GMII mode.)
Supported Operations
The LXT1000 Gigabit functions include:
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Far-end crosstalk (FEXT)
Propagation delay variations between channels of up to 120 ns.
Extraneous tones that have been coupled into the receive path.
Link detection.
Normal packet operation. Generation of SSD, ESD, csreset, idle, error handling, and false
carrier detection.
Collision detection for half-duplex operation.
Carrier extension with/without errors, supporting frame bursting.
Gigabit Ethernet Transceiver — LXT1000
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