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參數(shù)資料
| 型號： | XRT75R12DIB |
| 廠商： | EXAR CORP |
| 元件分類： | 數(shù)字傳輸電路 |
| 英文描述： | TWELVE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH SONET DESYNCHRONIZER |
| 中文描述： | DATACOM, PCM TRANSCEIVER, PBGA420 |
| 封裝： | 35 X 35 MM, TBGA-420 |
| 文件頁數(shù)： | 102/131頁 |
| 文件大小： | 717K |
| 代理商： | XRT75R12DIB |
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XRT75R12D
REV. P1.0.1
TWELVE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH SONET DESYNCHRONIZER
PRELIMINARY
97
What does this mean at the "Destination" PTE
In this case, this DS3 signal (which has now been mapped into an STS-1 data-stream) will be transported
across the SONET network. As this STS-1 signal arrives at the "Destination" PTE, this PTE will extract (or de-
map) this DS3 data from each incoming STS-1 SPE. Now, in this case most (e.g., 177/178.8) of the incoming
STS-1 SPEs will contain 5592 DS3 data-bits. Therefore, the nominal data rate of the DS3 signal being de-
mapped from SONET will be 44.736Mbps. However, in approximately 1 out of every 178 incoming STS-1
SPEs, the SPE will carry 5593 DS3 data-bits. This means that (during these times) the data rate of the de-
mapped DS3 signal will have an instantaneous frequency that is greater than 44.736Mbps. These "excursion"
of the de-mapped DS3 data-rate, from the nominal DS3 frequency can be viewed as occurrences of "mapping/
de-mapping" jitter. Since each of these "bit-stuffing" events involve the insertion of one DS3 data bit, we can
say that the amplitude of this "mapping/de-mapping" jitter is approximately 1UI-pp. From this point on, we will
be referring to this type of jitter (e.g., that which is induced by the mapping and de-mapping process) as "de-
mapping" jitter.
Since this occurrence of "de-mapping" jitter is periodic and occurs once every 22.35ms, we can state that this
jitter has a frequency of 44.7Hz.
8.2.2.3
The 44.736Mbps - 1ppm Case
In this case, let us assume that a DS3 signal, with a bit-rate of 44.736Mbps - 1ppm is being mapped into an
STS-1 signal with a bit-rate of 51.84Mbps + 0ppm. In this case, the following this will occur.
In general, most of the STS-1 SPEs will each transport 5592 DS3 data bits.
However, within a "one-second" period a DS3 signal that has a bit-rate of 44.736Mbps - 1ppm will deliver
approximately 45 too few bits below that of a DS3 signal with a bit-rate of 44.736Mbps + 0ppm. This means
that this particular signal will need to "positive-stuff" or exclude a DS3 data bit from mapping every (1/44.736)
= 22.35ms. In other words, we will need to avoid mapping this DS3 data-bit about one in every
(22.35ms*8000) = 178.8 STS-1 SPEs.
What does this mean at the "Source" PTE
All of this means that as the "Source" PTE maps this DS3 signal, with a data rate of 44.736Mbps - 1ppm into
an STS-1 signal, most of the resulting "outbound" STS-1 SPEs will transport 5592 DS3 data bits (e.g., 3 Stuff
Opportunity bits will be carrying DS3 data bits, the remaining 6 Stuff Opportunity bits are "stuff" bits). However,
in approximately one out of 178.8 "outbound" STS-1 SPEs, there will be a need for a "positive-stuffing" event.
Whenever these "positive-stuffing" events occur then (for these particular STS-1 SPEs) the SPE will carry only
5591 DS3 data bits (e.g., in this case, only 2 Stuff Opportunity bits will be carrying DS3 data-bits, and the
remaining 7 Stuff Opportunity bits are "stuff" bits).
Figure 47 presents an illustration of the STS-1 SPE traffic that will be generated by the "Source" PTE, during
this condition.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| XRT75R12DIB-F | 功能描述:網(wǎng)絡(luò)控制器與處理器 IC 12 Channel 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 |
| XRT75R12DIB-L | 功能描述:LIN 收發(fā)器 Synch RoHS:否 制造商:NXP Semiconductors 工作電源電壓: 電源電流: 最大工作溫度: 封裝 / 箱體:SO-8 |
| XRT75R12ES | 功能描述:時鐘合成器/抖動清除器 12CH T3/E3/STS1LIUJA 3.3V W/REDUNDANCY RoHS:否 制造商:Skyworks Solutions, Inc. 輸出端數(shù)量: 輸出電平: 最大輸出頻率: 輸入電平: 最大輸入頻率:6.1 GHz 電源電壓-最大:3.3 V 電源電壓-最小:2.7 V 封裝 / 箱體:TSSOP-28 封裝:Reel |
| XRT75R12IB | 功能描述:外圍驅(qū)動器與原件 - PCI 12CH E3/DS3/STS W/JITTER R3 TECH 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 |
| XRT75R12IB-F | 功能描述:外圍驅(qū)動器與原件 - PCI 12 Channel 3.3V-5V temp -45 to 85C 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 |
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