无线传输距离的计算方法
无线传输距离可以根据天线增益值来计算的 <p>最好能举例说明一下,便于新手学习</p> <div style="LAYOUT-GRID:15.6pt none" class="Section0"><p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0">
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p></span></p><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">、计算距离</span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">1<font face="宋体">、链路预算和</font><font face="Arial">FSPL</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">在计算之前我们还需要确定两个概念。链路预算(<font face="Arial">Link Budget</font><font face="宋体">),常常代表了接收信号时的余量(</font><font face="Arial">Fade Margin</font><font face="宋体">)。其计算方法是接收功率</font><font face="Arial">-</font><font face="宋体">接收灵敏度,我们</font><font face="Arial">AP</font><font face="宋体">在扫频时可以看到的</font><font face="Times New="New"Roman">“</font><font face="宋体">信号强度</font><font face="Times New="New"Roman">”</font><font face="宋体">,其实就是这个链路预算的体现</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">一般预算值在<font face="Arial">10dB</font><font face="宋体">以上时,对于</font><font face="Arial">wifi</font><font face="宋体">系统来说可以成功连接通信。请注意,扫频时</font><font face="Arial">AP</font><font face="宋体">用的是</font><font face="Arial">1Mbps</font><font face="宋体">的灵敏度,这个值大大低于</font><font face="Arial">54Mbps</font><font face="宋体">时的灵敏度,所以如果想连通并且速率维持在</font><font face="Arial">54Mbps</font><font face="宋体">,那么必须以</font><font face="Arial">54Mbps</font><font face="宋体">的灵敏度代入接下来的公式去计算。</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">FSPL(Free Space Path-Loss)<font face="宋体">自由空间路径损耗,反映了信号在理想无干扰无障碍的环境中传播时的损耗,空气中可近似看成</font><font face="Arial">FSPL</font><font face="宋体">情况,其计算方式为</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">FSPL(dB) = 20lg(d) + 20lg(f) + 32.44</span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">d <font face="宋体">表示视距传输距离,单位 </font><font face="Arial">km</font><font face="宋体">;</font><font face="Arial">f </font><font face="宋体">表示无线信号频率,单位 </font><font face="Arial">MHz</font><font face="宋体">。在 </font><font face="Arial">802.11 b/g</font><font face="宋体">无线环境下,因为工作频率都是 </font><font face="Arial">2.4GHz</font><font face="宋体">,所以我们可以将上面公式简化为</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">FSPL(dB) = 20lg(d) + 100</span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">所以,现在开始吧!</span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">2<font face="宋体">、计算距离开始</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">我们假定链路预算(比较稳定的情况)为<font face="Arial">10</font><font face="宋体">~</font><font face="Arial">20dB</font><font face="宋体">之间,取</font><font face="Arial">10dB</font><font face="宋体">,那么有</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">链路预算<font face="Arial">(dB) = 10dB=</font><font face="宋体">预算接收功率</font><font face="Arial">(dBm) </font><font face="Times New="New"Roman">– </font><font face="宋体">接收灵敏度</font><font face="Arial">(dBm)</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">其中,预算的接收功率为</span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">预算接收功率<font face="Arial">= </font><font face="宋体">发射功率 </font><font face="Arial">+ </font><font face="宋体">发射天线增益 </font><font face="Times New="New"Roman">– </font><font face="Arial">FSPL + </font><font face="宋体">接收天线增益</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">结合这两个等式,有</span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">FSPL = <font face="宋体">发射功率 </font><font face="Arial">+ </font><font face="宋体">发射天线增益 </font><font face="Arial">+ </font><font face="宋体">接收天线增益 </font><font face="Times New="New"Roman">– </font><font face="宋体">接收灵敏度 </font><font face="Times New="New"Roman">– </font><font face="Arial">10dB</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">从上式可以看出,右侧等式中的各值都是已知的,左侧的<font face="Arial">FSPL</font><font face="宋体">由上式可以发现只有一个距离参数是未知的,学过解方程的应该都会解的吧。是不是很简单?</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">3<font face="宋体">、计算举例 </font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">假设某 <font face="Arial">54Mbps </font><font face="宋体">无线 </font><font face="Arial">AP </font><font face="宋体">的射频发射总功率为 </font><font face="Arial">20dBm</font><font face="宋体">,自带 </font><font face="Arial">3dBi </font><font face="宋体">天线,所以其 </font><font face="Arial">AP</font><font face="宋体">本身的发射功率为 </font><font face="Arial">17dBm</font><font face="宋体">。另一端的 </font><font face="Arial">AP</font><font face="宋体">型号相同,接收灵敏度在传输速率为</font><font face="Arial">54M </font><font face="宋体">时为</font><font face="Arial">-68dBm</font><font face="宋体">。这里假设链路预算为 </font><font face="Arial">20dB</font><font face="宋体">,那么有</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">FSPL = <font face="宋体">发射功率 </font><font face="Arial">+ </font><font face="宋体">发射天线增益 </font><font face="Arial">+ </font><font face="宋体">接收天线增益 </font><font face="Times New="New"Roman">– </font><font face="宋体">接收灵敏度 </font><font face="Times New="New"Roman">– </font><font face="宋体">链路预算 </font><font face="Arial">= 17 + 3 + 3 </font><font face="Times New="New"Roman">– </font><font face="Arial">(-68) </font><font face="Times New="New"Roman">– </font><font face="Arial">20 = 71 dB</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 0.55pt; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); VERTICAL-ALIGN: baseline; PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">代入 </span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">FSPL(dB) = 20lg(d) + 100 </span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">所以得出 </span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">d = 0.0355 km = 35.5 m</span></p></div> 好东西啊 <div style="LAYOUT-GRID:15.6pt none" class="Section0">
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 160%; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">无线传输时的影响因素</span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 160%; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">1<font face="宋体">、</font><font face="Arial">Fresnel Zone</font></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 160%; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p><img src="http://www.wi-gadget.com/wp-content/uploads/2009/05/fresnel_zone-300x194.jpg"/></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 160%; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); PADDING-TOP: 0pt" class="p0"><span><a href="http://www.wi-gadget.com/wp-content/uploads/2009/05/fresnel_zone.jpg"><span></span></a></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 160%; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">菲涅耳带<font face="Arial">(Fresnel Zone)</font><font face="宋体">形象地描述了无线链路的空间模型。它是一个类似于橄榄球状的区域,中间凸,两头尖。视距传输模型中,我们规定,在第一菲涅尔带内 </font><font face="Arial">60%</font><font face="宋体">的区域不能有障碍物;</font><font face="Arial">60%</font><font face="宋体">的区域指的是菲涅尔带的半径按比例缩小到 </font><font face="Arial">60%</font><font face="宋体">。</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 160%; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">至于这个区域怎么算,大家可以去<font face="Arial">wiki</font><font face="宋体">一下,这里不赘述了。</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 160%; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">2<font face="宋体">、障碍阻挡</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 160%; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">如果传输模型中档了一堵墙,那么要怎么去计算?</span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 160%; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">一般来说,最简单的办法就是加上墙带来的损耗,一般像玻璃的损耗在<font face="Arial">3dB</font><font face="宋体">左右,钢筋水泥就说不准了,一般在</font><font face="Arial">13dB</font><font face="宋体">以上。</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; PADDING-BOTTOM: 0pt; LINE-HEIGHT: 160%; MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; PADDING-LEFT: 0pt; PADDING-RIGHT: 0pt; MARGIN-BOTTOM: 7.5pt; BACKGROUND: rgb(255,255,255); PADDING-TOP: 0pt" class="p0"><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'">3<font face="宋体">、无线干扰、天线对准、空气密度、天气影响。。。</font></span><span style="FONT-FAMILY: 'Arial'; BACKGROUND: rgb(255,255,255); COLOR: rgb(51,51,51); FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p style="MARGIN-TOP: 0pt; MARGIN-BOTTOM: 0pt" class="p0"><span style="FONT-FAMILY: 'Times New="New"Roman'; FONT-SIZE: 10.5pt; mso-spacerun: 'yes'"><o:p>北京众诚天合集成科技有限公司专业做无线系统集成,无线视频监控,有需要的敬请至电010-62521550 QQ;847309052</o:p></span></p></div><!--EndFragment--> <p> ARGtek高功率无线产品<br/> 1.2.4g:300m 1w路由器,300m 1w室外无线网桥,4w放大器,<br/> 2.5.8g:1w路由器,网卡,网桥,放大器<br/> 3.2.4g+5.8g双模无线路由,无线网卡,无线网桥<br/> 4.宽带叠加网卡</p>
<p> 广州瑞凌网络:020-22001048 22001049 QQ:767544887(注明千家)王克玮:13760771818 email:sss1860@126.com www.argtek.com 全国招商 性价比级高!</p> <p>好文章</p> 好文章 谢谢 学习了。。 <p>很好</p>
<p> </p> ddddddddddddddddddddddddddddddddddddddd ccccss 貌似很复杂。呵呵 一言难尽。。。。还是要靠实际情况来定啊 有点看不懂 <p>收藏了,谢谢</p> 好文 学习一下 收藏了 嗯,不错,这只是数字上,真正实际用到的,还是要以当时的环境条件来决定。 <p>赞</p>
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