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通信工程师必背：快速口算转换dBm与W小技巧

<p>作为一个通信工程师，尤其是做RF的，不能快速转换dBm与W怎么行？</p>

<p>今天我们来介绍一个经典的可将dBm转换为W的口算方法。</p>

<p>该口算规律为：“1个基准”和“2个原则”。</p>

<p>1个基准：</p>

<p><img alt="基准1" data-entity-type="file" data-entity-uuid="fa5c9d20-6816-48f4-a253-9f3d944c3fa4" src="/sites/default/files/inline-images/%E5%9F%BA%E5%87%861.png" /></p>

<p>2个原则：</p>

<p>1）＋3dB，功率乘以2；－3dB，功率除以2</p>

<p><img alt="基准2" data-entity-type="file" data-entity-uuid="ee31d4d2-86ab-4b4e-b00c-e2b3d11c269a" src="/sites/default/files/inline-images/%E5%9F%BA%E5%87%862.png" /></p>

<p>2）＋10dB，功率乘以10；－10dB，功率除以10</p>

<p><img alt="基准3" data-entity-type="file" data-entity-uuid="3fb0d90c-17ac-4e08-81bd-e6160c92ba48" src="/sites/default/files/inline-images/%E5%9F%BA%E5%87%863.png" /></p>

<p>几乎所有整数的dBm都可用以上的“1个基准”和“2个原则”转换为W。</p>

<p>例1：100mW + 3dB = ？W</p>

<p>100mW + 3dB = 100×2 = 200（mW）</p>

<p>例2：100mW + 10dB = ？W</p>

<p>100mW + 10dB = 100 × 10 = 1000（mW）</p>

<p>例3：100mW + 7dB = ？W</p>

<p>100mW + 7dB = 100mW + （10dB - 3dB）<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;=100 × 10 ÷ 2&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 500（mW）</p>

<p>例5：44dBm= ? W<br />
　　　　&nbsp;<br />
44dBm = 30dBm + 10dB + 10dB－3dB－3dB<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; =1W×10×10÷ 2 ÷ 2&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 25W</p>

<p>例2：32dBm= ? W<br />
　　　　&nbsp;<br />
32dBm = 30dBm + 3dB + 3dB + 3dB + 3dB－10dB&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 1W×2×2×2×2÷10&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 1.6W</p>

<p>+1dB和+2dB的计算技巧<br />
　　<br />
+1dB = +10dB－3dB－3dB－3dB&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = X×10×1/2×1/2×1/2&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = X×1.25</p>

<p>+2dB = －10dB+3dB+3dB+3dB+3dB&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = X×0.1×2×2×2×2&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = X×1.6</p>

<p>在计算中，有时候也可以根据上面的规律变换为－1dB和－2dB，达到快速口算的目的，即：<br />
　　<br />
－1dB = －10dB+3dB+3dB+3dB&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= X×0.1×2×2×2&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= X×0.8<br />
　　<br />
－2dB = －3dB+1dB&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = X×1/2×1.25&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = X×0.625<br />
　　<br />
例1：</p>

<p>51dBm = 30dBm+10dB+10dB+1dB&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 1W×10×10×1.25&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 125W<br />
　　<br />
例2：</p>

<p>38dBm = 30dBm + 10dB－2dB&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 1W×10×0.625&nbsp;<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 6.25W</p>

<p>是不是很简单啊？你记住了吗？</p>

<p>文章转载自：<a href="https://mp.weixin.qq.com/s?__biz=MzA3MTA3OTIwMw==&amp;mid=2652524087&am…; id="js_name">网优雇佣军</a>，转载此文目的在于传播相关技术知识，版权归原作者所有，如涉及侵权，请联系小编删除(联系邮箱：service@eetrend.com )。</p>