电磁辐射照射的场强单位及其换算

杰克逊 · 发表于 2012-4-25 23:12:47

<html><head><meta http-equiv="Content-Type" content="text/html; charset=gb2312"><meta name="GENERATOR" content="Microsoft FrontPage 4.0"><meta name="ProgId" content="FrontPage.Editor.Document"><title>电磁干扰场强单位及其换算</title></head><body> <o:p></o:p>摘要：电磁干扰场强单位及其换算，是广大<a href=http://www.stdjia.com style=text-decoration:underline;font-size:14px;color:#F70968; target=_blank>电磁兼容</a>工作者经常遇到的、关切的问题之一。电磁干扰场强既有电场强度、磁场强度和功率通量密度等基本单位，又有分贝制导出。在某些情况下，单位之间还可相互换算。本文将就这些单位的使用及换算作一简要的介绍。 一、电磁干扰场强的基本单位高频、微波电磁干扰场强有三种基本单位：电场强度V/m、磁场强度A/m和功率通量密度W/m2。<o:p></o:p> 在测量电场时，若仪器的表头刻度用的是电场强度单位时，则用V/m单位表示之。所测干扰场强小于1V/m时，可用m V /m、µV/m单位。<o:p></o:p>当使用环天线、框天线或磁性天线等来测量磁场，且仪器的表头刻度按磁场强度单位A/m刻度时，则可用A/m、 mA /m、µA/m单位表示之。<o:p></o:p>当电磁场频率高至微波段时，由于对电场、磁场的单独测量在技术上有一定困难；或者功率密度测量比电场、磁场测量要方便，所以可采用功率通量密度测量。功率通量密度的单位为W/ m2。国外生产的全向宽带场强仪、辐射危险计，因其工频率范围极宽，从260KHZ~26GHZ、，故测试电路中实现|E|2、|H|2较为方便。因此，大多采用功率通量密度测量，并以mW /Cm2为表头刻单位。强场仪测得的功率通量密度是Poyn-ting向量模的时间平均值，亦代表电磁场的强度。它的单位W/m2和电场强度单位V /m、磁场强度单位A/m同为电磁干扰场强的基本单位。它们的地位是等同的。<o:p></o:p>一、电磁干扰场强单位间的相互换算<o:p></o:p>在一般情况下，V/m、A/m和mW /Cm之间不能相互换算。只有在被测场为平面波情况下，三者间才能相互换算。否则，只能“等效换算”。何谓平面波？凡远离发射天线，在自由空间中传播的电磁波，皆为平面波。根据电磁场理论，在平面波情况下，S=ZoH2=E2/Zo在自由空间中，Z=120π≈376.7Ω，代入上式后可得： E单位为V/m2，S单位为mW /C m2。值得指出的是：通常A、B波段（10Khz~30MHZ<span style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman"

杰克逊 · 发表于 2012-4-25 23:12:53

>）的干扰场强测量仪（例如德R/S公司的ESH3、日本Anritu公司的ML428B）使用环形天线进行测量。虽然环形天线只对磁场分量起作用，但在自由空间中，由于E=Z0H（称等效电场分量），故表头可用等效电场分量刻度。但对近区场而言，电场E 和磁场H并无确定的比例关系。可能E很大，H很小，也可能H很大，E 很小；需视场源情况而定。此时，公式（1）~（2）已不成立，充其量只能“等效换算“，仅供参考而已。二、电磁干扰场强的分贝制单位在电磁干扰场强的测试中，往往会遇到量值相差非常悬殊（甚至千百万倍的信号）。为了便于表达、叙述和运算（变乘除为加减），常采用对数单位——分贝（dB）。分贝（dB）是表征两个功率电平比值的单位，即A=10lgp2/p1（dB）…………..（3）鉴于p=U2/R=I2R，因此下述表达式A=20lg U2/U2=20lg I1/I220lg………….. (4)亦被接受为dB的定义，但这针对的是同一阻抗。分贝制单位在电磁干扰场强计量测试中的用法有如下三种：（1） 表示信号传输系统中任意两点间功率（或电压）的相对大小，或空间某两点电磁干扰场强的相对大小。例1 RR3A型干扰场强测量仪。当其输入端接入20dB固定衰减器，则其测量范围扩大20dB。这表示仪器输入电平前后相差20dB。例2 用RAAM4A型全向宽带场强仪测量空间A<span

杰克逊 · 发表于 2012-4-25 23:12:59

style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">点的功率通量密度为20 mW /Cm2，测量空间B点的功率通量密度为20 wμ/Cm2，则A、B两点功率通量密度相差30dB。例3 有20m长电缆一根，馈入1000MHZ高频信号电压100mV，测其输出电压只有5mV，则该电缆在1000MHZ频率点上损耗为6dB。（2） 在指定参考电平（电压或电场强度）时，可用分贝表示电压或电场强度的绝对值。此参考电平通称为零电平。 在干扰、场强测量仪的检定测试中，常常对测量接收机施加高频标准小电 压，以检定其端电压测量精度。定义1μV=0dBμV（简写为dBμ），此即“分贝微伏”的由来。同样，定义场强1μV/m==0dBμV/m(简写为dBμ)，称“分贝微伏/米”。<o:p></o:p>尚须指出，dBμ只对小电压使用较方便，而对大电压则可采用dBV（分贝伏，1V=0dBV）；或dBmV（分贝毫伏，1mV=odBmV）。另外，“80dB电压“这种称谓是不恰当的。确切的说法应是“80dBμ电压”，因为dB是电压比，而不是电压值。<o:p></o:p>表1给出电场强度与dBμV/m对应关系。表1电场强度与dBμV/m的对应关系<table border="1" cellspacing="0" cellpadding="0" style="margin-left:42.0pt; border-collapse:collapse;border:none;mso-border-alt:solid windowtext .5pt; mso-padding-alt:0cm 5.4pt 0cm 5.4pt"><tr><td width="58" valign="top" style="width:43.7pt;border:solid windowtext .5pt; padding:0cm 5.4pt 0cm 5.4pt">μV/m</td><td width="57" valign="top" style="width:42.55pt;border:solid windowtext .5pt; border-left:none;mso-border-left-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt">1</td><td width="57" valign="top" style="width:42.55pt;border:solid windowtext .5pt; border-left:none;mso-border-left-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt">10</td><td width="57" valign="top" style="width:42.55pt;border:solid windowtext .5pt; border-left:none;mso-border-left-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt">102</td><td width="57" valign="top" style="width:42.55pt;border:solid windowtext .5pt; border-left:none;mso-border-left-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt">103</td><td width="57" valign="top" style="width:42.55pt;border:solid

杰克逊 · 发表于 2012-4-25 23:13:05

windowtext .5pt; border-left:none;mso-border-left-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt">104</td><td width="57" valign="top" style="width:42.55pt;border:solid windowtext .5pt; border-left:none;mso-border-left-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt">105</td><td width="57" valign="top" style="width:42.55pt;border:solid windowtext .5pt; border-left:none;mso-border-left-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt">106</td><td width="57" valign="top" style="width:42.55pt;border:solid windowtext .5pt; border-left:none;mso-border-left-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt">107</td></tr><tr><td width="58" valign="top" style="width:43.7pt;border:solid windowtext .5pt; border-top:none;mso-border-top-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt">dBμ</td><td width="57" valign="top" style="width:42.55pt;border-top:none;border-left: none;border-bottom:solid windowtext .5pt;border-right:solid windowtext .5pt; mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt; padding:0cm 5.4pt 0cm 5.4pt">0</td><td width="57" valign="top" style="width:42.55pt;border-top:none;border-left: none;border-bottom:solid windowtext .5pt;border-right:solid windowtext .5pt; mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt; padding:0cm 5.4pt 0cm 5.4pt">20</td><td width="57" valign="top" style="width:42.55pt;border-top:none;border-left: none;border-bottom:solid windowtext .5pt;border-right:solid windowtext .5pt; mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt; padding:0cm 5.4pt 0cm 5.4pt">40 </td><td width="57" valign="top" style="width:42.55pt;border-top:none;border-left: none;border-bottom:solid windowtext .5pt;border-right:solid windowtext .5pt; mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt; padding:0cm 5.4pt 0cm 5.4pt">60</td><td width="57" valign="top" style="width:42.55pt;border-top:none;border-left: none;border-bottom:solid windowtext .5pt;border-right:solid windowtext .5pt; mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt; padding:0cm 5.4pt 0cm 5.4pt">80</td><td width="57" valign="top" style="width:42.55pt;border-top:none;border-left: none;border-bottom:solid windowtext .5pt;border-right:solid windowtext .5pt; mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt; padding:0cm 5.4pt 0cm 5.4pt">100</td><td width="57" valign="top" style="width:42.55pt;border-top:none;border-left: none;border-bottom:solid windowtext .5pt;border-right:solid windowtext .5pt; mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt; padding:0cm 5.4pt 0cm 5.4pt">120</td><td width="57" valign="top" style="width:42.55pt;border-top:none;border-left: none;border-bottom:solid windowtext .5pt;border-right:solid windowtext .5pt; mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt; padding:0cm 5.4pt 0cm 5.4pt">140</td></tr></table></o:p>例4 说某干扰电值为86dBμ，何意？<o:p></o:p>答：86dBμ是80和6这两个数字之和。而80dB、6dB的对应电压比为104 2.故有：104×2=2×104 =20×103 。 因此，86dBμ即为20mV。<o:p></o:p> 例五说场强仪的量程是6~126 dBμ，何意？<o:p></o:p><span style="mso-tab-count: 1; mso-fareast-font-family:

杰克逊 · 发表于 2012-4-25 23:13:11

PMingLiU" lang="EN-US"> 答：该场强仪的量程上限是2×10μV/m，或2V/m。量程下限为2×10μV/m，即 2μV/m。 （3）用分贝表示电压或场强的误差大小。 例六某场强标准装置的不确定度为±1dB，对应的百分误差是多少？ 答：不确定度±1dB意味着百分误差为+12.2℅,-10.87℅。 例七某干扰场强测量仪的不确定度为±3dB，对应百分误差是多少？ 答：+41.25℅,-29.2℅。 表2 电场强度分贝误差与百分误差对照表。供大家引用参考。</o:p> <o:p>表2 电场强度分贝——百分误差对照表</o:p><table border="1" cellspacing="0" cellpadding="0" align="left" style="border-collapse: collapse; mso-border-alt: solid windowtext .5pt; mso-table-overlap: never; mso-table-tspace: 9.0pt; mso-table-bspace: 9.0pt; mso-table-anchor-vertical: paragraph; mso-table-anchor-horizontal: column; mso-table-left: 0cm; mso-table-top: bottom; mso-padding-alt: 0cm 5.4pt 0cm 5.4pt; border-style: none; border-width: medium" width="851"><tr><td width="178" valign="top" style="border: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">分贝误差dB</td><td width="136" valign="top" style="mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top: .5pt solid windowtext; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">百分误差</td><td width="172" valign="top" style="mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top: .5pt solid windowtext; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">分贝误差</td><td width="174" valign="top" style="mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top: .5pt solid windowtext; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">百分误差</td></tr><tr><td width="178" valign="top" style="

杰克逊 · 发表于 2012-4-25 23:13:17

mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">o.1</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">1.16</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-0.1</td><td width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-1.14</td></tr><tr><td width="178" valign="top" style="mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">0.2</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">2.32</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-0.2</td><td width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-2.27</td></tr><tr><td width="178" valign="top" style="mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">0.3</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">3.5I</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-O.3</td><td

杰克逊 · 发表于 2012-4-25 23:13:23

width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-3.39</td></tr><tr><td width="178" valign="top" style="mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">O.4</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">4.7I</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-0.4</td><td width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-4.50</td></tr><tr><td width="178" valign="top" style="mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">0.5</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">5.93</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-0.5</td><td width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-5.59</td></tr><tr><td width="178" valign="top" style="mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">0.6</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly"><font color="#000080"

杰克逊 · 发表于 2012-4-25 23:13:29

face="华文细黑">7.15</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-0.6</td><td width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-6.67</td></tr><tr><td width="178" valign="top" style="mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">0.7</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">8.39</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-0.7</td><td width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-7.74</td></tr><tr><td width="178" valign="top" style="mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">0.8</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">9.65</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-0.8</td><td width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-8.41</td></tr><tr><td width="178" valign="top" style="mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;

杰克逊 · 发表于 2012-4-25 23:13:35

mso-height-rule:exactly">0.9</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">10.92</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-0.9</td><td width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-9.84</td></tr><tr><td width="178" valign="top" style="mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">1.0</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">12.20</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-1.0</td><td width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-10.87</td></tr><tr><td width="178" valign="top" style="mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">1.5</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">18.85</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-1.5</td><td width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;

杰克逊 · 发表于 2012-4-25 23:13:41

mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-15.86</td></tr><tr><td width="178" valign="top" style="mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">2.0</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">25.89</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-2.0</td><td width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-20.56</td></tr><tr><td width="178" valign="top" style="mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">2.5</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">33.35</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-2.5</td><td width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-25.01</td></tr><tr><td width="178" valign="top" style="mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">3.0</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">41.25</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;

杰克逊 · 发表于 2012-4-25 23:13:47

mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-3.0</td><td width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-29.20</td></tr><tr><td width="178" valign="top" style="mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">3.5</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">49.62</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-3.5</td><td width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-33.16</td></tr><tr><td width="178" valign="top" style="mso-border-top-alt: solid windowtext .5pt; border-left: .5pt solid windowtext; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">4.0</td><td width="136" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">58.49</td><td width="172" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-4.0</td><td width="174" valign="top" style="mso-border-top-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; border-left-style: none; border-left-width: medium; border-right: .5pt solid windowtext; border-top-style: none; border-top-width: medium; border-bottom: .5pt solid windowtext; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; padding-bottom: 0cm" align="center"><p class="MsoNormal" style="tab-stops:43.5pt;mso-element:frame;mso-element-frame-vspace: 9.0pt;mso-element-wrap:auto;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal: column;mso-element-left:.05pt;mso-element-top:bottom;mso-height-rule:exactly">-36.90</td></tr></table> <o:p></o:p> <o:p></o:p> <o:p></o:p> <o:p></o:p> <o:p></o:p> <o:p></o:p> <o:p></o:p> <o:p></o:p><p class="MsoNormal" style="

杰克逊 · 发表于 2012-4-25 23:13:53

tab-stops:43.5pt"> <o:p></o:p> <o:p></o:p>三、dBm与dBμ的换算 近年来，频谱仪在电磁干扰测量中使用日见广泛。美国hp8568B电磁干扰测量仪、日本Auritsu公司生产的MS2601A电磁干扰测量仪和德国R/S的ESA-1型<a href=http://www.stdjia.com style=text-decoration:underline;font-size:14px;color:#F70968; target=_blank>EMI</a>测量仪等都是以频谱仪为主机附加其它功能发展而成的。其电压显示单位多为dBm，亦有用dBμ的。另外，从国外进的合成信号发生器中，有的只标有dBm和dBμ。如何换算呢？<o:p></o:p>（1） dBm的定义。DBm是dBmW的简写，称为“分贝毫瓦”。<o:p></o:p> 1mw=0dBm……………(5)<o:p></o:p>上式是以1mW功率电平为参考基准的绝对功率值。正的dBm表示大于1mW功率，负的dBm表示小于1mW的功率。此可见，采用dBm既可表示很小的功率，亦可表示很大的功率<o:p></o:p>PdBm=101gPmw………………(6)<o:p></o:p>例8 功率信号发生器XG26，最小输出功率10-6mW,最大输出功率27W。请换算成dBm。<o:p></o:p>答：最小输出功率为-60dBm，最大输出功率为+44.3dBm。<o:p></o:p>实践中，有时还可遇到BW（分贝瓦）这个单位。其定义为：<o:p></o:p>PdBw=101gPmw…………….(7)<o:p></o:p> 1W=0dBW…………………(8)<o:p></o:p>它是以1W为参考电平的绝对功率值。大于1W为正dBW，小于1W为负dBW。<o:p></o:p>显然0dBW=30dBm……… …………(9)<o:p></o:p>(2)dBm与dBμ的换算<o:p></o:p>对50Ω源阻抗的信号发生器而言，当其输出功率为1mW（0dBm）时，其端电压输出应为<o:p></o:p>Uuv=√50p×106…………………(10)<o:p></o:p>代入P=1mW=10-3W,可得UμV：<o:p></o:p>UμV=√50×10-3×106=223606.7978其dBμ值为：UdBμ=201g223606.7978=106.9897≈107………………(11)<o:p></o:p>例9用频谱仪测得干扰电压为-87 dBm，它等于多少dBμ？<o:p></o:p>答：-87+107=20dBμ，即10µV。<o:p></o:p>四、绝对分贝值的加减问题<o:p></o:p>应当指出，在电磁干扰场强的计量测试中，引入分贝制单位后，把乘除变为加减，大方便了表达、叙述和运算。但是，有些分贝制单位是不能直接相加减的，这并不是因为什么相位关系。下面举例说明：<o:p></o:p>例1 40 dBμ+ 40 dBμ/=80 dBμ，为什么？<o:p></o:p>答：40dBµ=100µV,40dBµ+40dBµ=200µV 201g200(µV)=46 dBµ.<span lang="EN-US" style="

杰克逊 · 发表于 2012-4-25 23:13:59

mso-fareast-language: ZH-TW"><o:p></o:p>例2 0dBm+0dBm/=0dBm，为什么？<o:p></o:p>答:0dBm=1mW 0dBm+0dBm=2mW<o:p></o:p><span lang="EN-US" style="font-size: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: Times New Roman; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA"> 101g2=3dBm。</body></html>

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