参数资料
| 型号： | XRT75L00DIV-F |
| 厂商： | Exar Corporation |
| 文件页数： | 60/92页 |
| 文件大小： | 0K |
| 描述： | IC LIU E3/DS3/STS-1 SGL 52TQFP |
| 标准包装： | 96 |
| 类型： | 线路接口装置（LIU） |
| 驱动器/接收器数： | 1/1 |
| 规程： | DS3，E3，STS-1，SONET |
| 电源电压： | 3.135 V ~ 3.465 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 52-LQFP |
| 供应商设备封装： | 52-TQFP（10x10） |
| 包装： | 托盘 |
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XRT75L00D
REV. 1.0.2
E3/DS3/STS-1 LINE INTERFACE UNIT WITH SONET DESYNCHRONIZER
58
As a consequence, no "Mapping/De-Mapping" Jitter or Wander is induced in the "Ideal Case".
9.2.2.2
The 44.736Mbps + 1ppm Case
The "above example" was a very ideal case. In reality, there are going to be frequency offsets in both the DS3
and STS-1 signals. For instance Bellcore GR-499-CORE mandates that a DS3 signal have a bit rate of
44.736Mbps ± 20ppm. Hence, the bit-rate of a "Bellcore" compliant DS3 signal can vary from the exact correct
frequency for DS3 by as much of 20ppm in either direction. Similarly, many SONET applications mandate that
SONET equipment use at least a "Stratum 3" level clock as its timing source. This requirement mandates that
an STS-1 signal must have a bit rate that is in the range of 51.84 ± 4.6ppm. To make matters worse, there are
also provisions for SONET equipment to use (what is referred to as) a "SONET Minimum Clock" (SMC) as its
timing source. In this case, an STS-1 signal can have a bit-rate in the range of 51.84Mbps ± 20ppm.
In order to convey the impact that frequency offsets (in either the DS3 or STS-1 signal) will impose on the bit-
stuffing behavior, and the resulting bit-rate, intrinsic jitter and wander within the DS3 signal that is being
transported across the SONET network; 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
things will occur.
In general, most of the STS-1 SPE's will each transport 5592 DS3 data bits.
However, within a "one-second" period, a DS3 signal that has a bit-rate of 44.736Mbps + 1 ppm will deliver
approximately 44.7 additional bits (over and above that of a DS3 signal with a bit-rate of 44.736Mbps + 0
ppm). This means that this particular signal will need to "negative-stuff" or map in an additional DS3 data bit
every (1/44.736 =) 22.35ms. In other words, this additional DS3 data bit will need to be mapped into about
one in every (22.35ms 8000 =) 178.8 STS-1 SPEs in order to avoid dropping any DS3 data-bits.
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, as in the
"Ideal" case). However, in approximately one out of 178.8 "outbound" STS-1 SPEs, there will be a need to
insert an additional DS3 data bit within this STS-1 SPE. Whenever this occurs, then (for these particular STS-
1 SPEs) the SPE will be carrying 5593 DS3 data bits (e.g., 4 Stuff Opportunity bits will be carrying DS3 data
bits, the remaining 5 Stuff Opportunity bits are "stuff" bits).
Figure 39 presents an illustration of the STS-1 SPE traffic that will be generated by the "Source" PTE, during
this condition.
FIGURE 39. AN ILLUSTRATION OF THE STS-1 SPE TRAFFIC THAT WILL BE GENERATED BY THE "SOURCE" PTE,
WHEN MAPPING IN A
DS3 SIGNAL THAT HAS A BIT RATE OF 44.736MBPS + 1PPM, INTO AN STS-1 SIGNAL
Source
PTE
Source
PTE
44.736Mbps + 1ppm
5592
DS3 Data
Bits
5592
DS3 Data
Bits
5592
DS3 Data
Bits
5592
DS3 Data
Bits
SPE # N
SPE # N+1
5592
DS3 Data
Bits
5592
DS3 Data
Bits
SPE # N+177
5593
DS3 Data
Bits
5593
DS3 Data
Bits
5592
DS3 Data
Bits
5592
DS3 Data
Bits
SPE # N+178
SPE # N+179
Extra DS3 Data
Bit Stuffed Here
STS-1 SPE Data Stream
相关PDF资料 |
PDF描述 |
|---|---|
| XRT75L00IV-F | IC LIU E3/DS3/STS-1 SGL 52TQFP |
| XRT75L02DIV-F | IC LIU E3/DS3/STS-1 2CH 100TQFP |
| XRT75L03DIV-F | IC LIU E3/DS3/STS-1 3CH 128LQFP |
| XRT75L03IV-F | IC LIU E3/DS3/STS-1 3CH 128LQFP |
| XRT75L04DIV-F | IC LIU E3/DS3/STS-1 4CH 176TQFP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| XRT75L00DIVTR | 功能描述:时钟合成器/抖动清除器 3.3V 1 CH E3/DS3/STS W/SONET DE-SYNCH RoHS:否 制造商:Skyworks Solutions, Inc. 输出端数量: 输出电平: 最大输出频率: 输入电平: 最大输入频率:6.1 GHz 电源电压-最大:3.3 V 电源电压-最小:2.7 V 封装 / 箱体:TSSOP-28 封装:Reel |
| XRT75L00DIVTR-F | 功能描述:时钟合成器/抖动清除器 3.3V 1 CH E3/DS3/STS W/SONET DE-SYNCH RoHS:否 制造商:Skyworks Solutions, Inc. 输出端数量: 输出电平: 最大输出频率: 输入电平: 最大输入频率:6.1 GHz 电源电压-最大:3.3 V 电源电压-最小:2.7 V 封装 / 箱体:TSSOP-28 封装:Reel |
| XRT75L00ES | 功能描述:时钟合成器/抖动清除器 1CH T3/E3/STS1 LIU+JA 3.3V RoHS:否 制造商:Skyworks Solutions, Inc. 输出端数量: 输出电平: 最大输出频率: 输入电平: 最大输入频率:6.1 GHz 电源电压-最大:3.3 V 电源电压-最小:2.7 V 封装 / 箱体:TSSOP-28 封装:Reel |
| XRT75L00IV | 功能描述:外围驱动器与原件 - PCI 3.3V 1 CH E3/DS3/STS W/JITTER ATTEN RoHS:否 制造商:PLX Technology 工作电源电压: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:FCBGA-1156 封装:Tray |
| XRT75L00IV-F | 功能描述:外围驱动器与原件 - PCI Sngl Chip LIU DS3/E3 RoHS:否 制造商:PLX Technology 工作电源电压: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:FCBGA-1156 封装:Tray |
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