DM9301 View Datasheet(PDF) - Davicom Semiconductor, Inc.
Part Name
Description
Manufacturer
DM9301 Datasheet PDF : 22 Pages
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DM9301
100Mbps Ethernet Fiber/Twisted Pair Single Chip Media Converter
100Base-TX to FX Operation
The block diagram in figure 2 provides an overview of the
functional blocks contained in the TX to FX media
converter interface.
The TX to FX interface contains the following functional
blocks:
• TX Digital Adaptive Equalization
• TX MLT-3 to NRZI
• TX Clock Recovery Module
• TX NRZI to NRZ Decoder
• TX Serial to Parallel Conversion
• TX Descrambler
• TX Code Group Alignment Monitor
• FX Parallel to Serial Conversion
• FX NRZ to NRZI
• FX PECL Transmitter
TX Signal Detect
The signal detect function meets the specifications
mandated by the ANSI XT12 TP-PMD100Base-TX
standards for both voltage thresholds and timing
parameters.
TX Digital Adaptive Equalization
When transmitting data at high speeds over copper
twisted pair cable, attenuation based on frequency
becomes a concern. In high speed twisted pair signaling,
the frequency content of the transmitted signal can vary
greatly during normal operation based on the randomness
of the scrambled data stream. This variation in signal
attenuation caused by frequency variations must be
compensated for to ensure the integrity of the received
data. In order to ensure quality transmission when
employing MLT-3 encoding, the compensation must be
able to adapt to various cable lengths and cable types
depending on the installed environment. The selection of
long cable lengths for a given implementation, requires
significant compensation which will be over-kill in a
situation that includes shorter, less attenuating cable
lengths. Conversely, the selection of short or intermediate
cable lengths requiring less compensation will cause
serious under-compensation for longer length cables.
TX Link
Status
Monitor
25M
OSC/XTAL
PECLTXO +/-
CGM
TX
PECL
TXMT
TX
NRZ
to
NRZI
TX Code-
group
Alignment
Monitor
FX
Parallel
to Serial
25M TPRXCLK
125M TPRXCLK
TX
Descrambler
TX
Serial to
Parallel
TX
NRZI
to
NRZ
TX
CRM
TX
MLT-3 to
NRZI
TX
Adaptive
EQ
TPRXI+/-
TX to FX Block Diagram
Figure 2
12
Final
Version: DM9301-DS-F02
May 8, 2000
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