參數(shù)資料
型號(hào)： XRT82D20
廠商： Exar Corporation
英文描述： Single Channel E1 Line Interface Unit(單通道E1線接口單元)
中文描述： 單通道E1線路接口單元（單通道素E1線接口單元）
文件頁(yè)數(shù)： 13/22頁(yè)
文件大?。?/td> 236K
代理商： XRT82D20
XRT82D20
SINGLE CHANNEL LINE INTERFACE UNIT
á
REV. 1.0.6
12
SYSTEM DESCRIPTION
The XRT82D20 is a single channel E1 transceiver
that provides an electrical interface for 2.048Mbps ap-
plications. XRT82D20 includes a receive circuit that
converts an ITU-T G.703 compliant bipolar signal into
a TTL compatible logic levels. The receiver also in-
cludes an LOS (Loss of Signal) detection circuit.
Similarly, in the Transmit Direction, the Transmitter
converts TTL compatible logic levels into a G.703
compatible bipolar signal.
The XRT82D20 consists of both a Receive Section,
Jitter Attenuator and Transmit Section; each of these
sections will be discussed below.
1.0
At the receiver input, cable attenuated AMI signal can
be coupled to the receiver using a capacitor or trans-
former. The receive data first goes through the peak
detector and data slicer for accurate data recov-
ery.The digital representation of the AMI signals go to
the clock recovery circuit for timing recovery and sub-
sequently to the decoder (if selected) for HDB3 de-
coding before being output to the RPOS/RData and
RNEG/LCV pins. The digital data output can be in
NRZ or RZ format depending the mode of operation
selected and with the option to be in dual-rail or single
rail mode.Clock timing recovery of the line interface is
accomplished by means of a digital PLL scheme
which has high input jitter tolerance.
The purpose of the Receive Output Interface block is
to interface directly with the Receiving Terminal
Equipment. The Receive Output Interface block out-
puts the data (which has been recovered from the in-
THE RECEIVE SECTION
coming line signal) to the Receive Terminal Equip-
ment via the RPOS and RNEG output pins.
If the Receive Section of the XRT82D20 has received
a Positive-Polarity pulse, via the RTIP and
RRing input pins, then the Receive Output Interface
will output a pulse at the RPOS output pin.
Similarly, if the Receive Section of the XRT82D20 has
received a Negative-Polarity pulse, via the RTIP and
RRing input pins, then the Receive Output Interface
will output a pulse at the RNEG output pin.
1.1
JITTER ATTENUATOR
To reduce frequency jitter in the transmit clock or re-
ceive clock, a crystal-less jitter attenuator is provid-
ed.The jitter attenuator can be selected either in the
transmit or receive path or it can be disabled.
1.2
THE TRANSMIT SECTION
In general, the purpose of the Transmit Section (with-
in the XRT82D20) is to accept TTL/CMOS level digital
data (from the Terminal Equipment), and to encode it
into a format such that it can:
1.
Be efficiently transmitted over coaxial- or twisted
pair cable at the E1 data rate; and
2.
Be reliably received by the Remote Terminal
Equipment at the other end of the E1 data link.
3.
Comply with the ITU-T G.703 pulse template
requirements, for E1 applications
A 2.048 mHz clock is applied to the TClk input pin
and NRZ data at the TPOS and TNEG input pins.
The Transmit Input Interface circuit will sample the
data, at the TPOS and TNEG input pins, upon the fall-
ing edge of TClk, as illustrated in Figure 8below.
In general, if the XRT82D20 samples a “1” on the
TPOS input pin, then the Transmit Section will ulti-
mately generate a positive polarity pulse via the TTIP
and TRing output pins (across a 1:2 transformer).
Conversely, if the XRT82D20 samples a “1” on the
TNEG input pin, then the Transmit Section of the de-
vice will ultimately generate a negative polarity pulse
via the TTIP and TRing output pins (across a 1:2
transformer).
1.3
T
HE
P
ULSE
S
HAPING
C
IRCUIT
The purpose of the Transmit Pulse Shaping circuit is
to generate Transmit Output pulses that comply with
F
IGURE
8. I
LLUSTRATION
ON
HOW
THE
XRT82D20 S
AMPLES
THE
DATA
ON
THE
TPOS
AND
TNEG
INPUT
PINS
TClk
TPOS
TNEG
tSU
tHO
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參數(shù)描述
XRT82D20_06 制造商:EXAR 制造商全稱:EXAR 功能描述:SINGLE CHANNEL E1 LINE INTERFACE UNIT
XRT82D20ES 功能描述:外圍驅(qū)動(dòng)器與原件 - PCI 1 CH E1 LIU RoHS:否 制造商:PLX Technology 工作電源電壓: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:FCBGA-1156 封裝:Tray
XRT82D20IW 功能描述:網(wǎng)絡(luò)控制器與處理器 IC Single Ch E1 LIU RoHS:否 制造商:Micrel 產(chǎn)品:Controller Area Network (CAN) 收發(fā)器數(shù)量: 數(shù)據(jù)速率: 電源電流（最大值）:595 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PBGA-400 封裝:Tray
XRT82D20IW-F 功能描述:網(wǎng)絡(luò)控制器與處理器 IC Single Ch; 3.3V-5V temp -45 to 85C RoHS:否 制造商:Micrel 產(chǎn)品:Controller Area Network (CAN) 收發(fā)器數(shù)量: 數(shù)據(jù)速率: 電源電流（最大值）:595 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PBGA-400 封裝:Tray
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