RMS請教

光学设计中经常遇到RMS，RMS是ROOT MEAN SQUARE得简写，他到底代表什么意思啊？？？大侠能否详细说明一下啊~~~真的需要了解~~~！！THANKS~~

<p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; mso-layout-grid-align: none;"><span lang="ZH-TW" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: PMingLiU; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma;">是</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Tahoma;">root mean square</span><span lang="ZH-TW" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: PMingLiU; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma;">，指的是均方根，单位应和</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Tahoma;">Gen</span><span lang="ZH-TW" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: PMingLiU; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma;">中的</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Tahoma;">Unit</span><span lang="ZH-TW" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: PMingLiU; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma;">是一样的</span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-fareast-language: ZH-CN;">；</span><span lang="ZH-TW" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: PMingLiU; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma;">和</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Tahoma;">asap</span><span lang="ZH-TW" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: PMingLiU; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma;">中定义的一样</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Tahoma; mso-fareast-language: ZH-CN; mso-fareast-font-family: 宋体;"><p></p></span></p>

<p>这个词在很多地方都有的，都表示均方根.</p>