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    參數(shù)資料
    型號: DM9331
    英文描述: Layout Guide
    中文描述: 布局指南
    文件頁數(shù): 14/43頁
    文件大?。?/td> 509K
    代理商: DM9331
    DM9331
    100 Mbps Twisted Pair/Fiber Ethernet Media Converter Chip
    14
    Preliminary
    Version: DM9331-DS-P02
    September 21, 2001
    100Base-TX Receiver
    The 100Base-TX receiver contains several function blocks
    that convert the scrambled 125Mb/s serial data to
    synchronous 2-bit nibble data that is then provided to the
    MCI.
    The receive section contains the following functional blocks:
    - Signal Detect
    - Digital Adaptive Equalizer
    - MLT-3 to NRZI Decoder
    - Clock Recovery Module
    - NRZI to NRZ Decoder
    - Serial to Parallel
    - Descrambler
    - Code Group Alignment
    - 4B5B Decoder
    Signal Detect
    The signal detect function meets the specifications
    mandated by the ANSI XT12 TP-PMD 100Base-TX
    Standards for both voltage thresholds and timing
    parameters.
    Adaptive Equalizer
    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. Therefore, the compensation or equalization must
    be adaptive to ensure proper conditioning of the received
    signal independent of the cable length.
    MLT-3 to NRZI Decoder
    The DM9331 decodes the MLT-3 information from the
    Digital Adaptive Equalizer into NRZI data.
    Clock Recovery Module
    The Clock Recovery Module accepts NRZI data from the
    MLT-3 to NRZI decoder. The Clock Recovery Module locks
    onto the data stream and extracts the 125MHz reference
    clock. The extracted and synchronized clock and data are
    presented to the NRZI to NRZ Decoder.
    NRZI to NRZ
    The transmit data stream is required to be NRZI encoded in
    for compatibility with the TP-PMD standard for 100Base-TX
    transmission over Category-5 unshielded twisted pair cable.
    This conversion process must be reversed on the receive
    end. The NRZI to NRZ decoder, receives the NRZI
    data stream from the Clock Recovery Module and
    converts it to a NRZ data stream to be presented to
    the Serial to Parallel conversion block.
    Serial to Parallel
    The Serial to Parallel Converter receives a serial data
    stream from the NRZI to NRZ converter, and converts
    the data stream to parallel data to be presented to the
    descrambler.
    Descrambler
    Because of the scrambling process required to control the
    radiated emissions of transmit data streams, the receiver
    must descramble the receive data streams. The
    descrambler receives scrambled parallel data streams from
    the Serial to Parallel converter, descrambles the data
    streams, and presents the data streams to the Code Group
    alignment block.
    Code Group Alignment
    The Code Group Alignment block receives un-aligned
    5B data from the descrambler and converts it into 5B
    code group data. Code Group Alignment occurs after
    the J/K is detected, and subsequent data is aligned on
    a fixed boundary.
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    相關(guān)代理商/技術(shù)參數(shù)
    參數(shù)描述
    DM9331A 制造商:未知廠家 制造商全稱:未知廠家 功能描述:
    DM9331AE 制造商:DAVICOM 制造商全稱:DAVICOM 功能描述:100 Mbps Twisted Pair/Fiber Ethernet Media Converter Chip
    DM9332 制造商:DAVICOM 制造商全稱:DAVICOM 功能描述:10/100Mbps Ethernet Fiber/Twisted Pair Single Chip Media Converter
    DM9332EP 制造商:DAVICOM 制造商全稱:DAVICOM 功能描述:10/100Mbps Ethernet Fiber/Twisted Pair Single Chip Media Converter
    DM9334 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:8-Bit Addressable Latch