工作小筆記-1 獨立線性與絕對線性

從一個專業的宅宅RD程式設計師，突然跳到電位器這領域，要學的東西真是像山一樣多，偏偏我的記憶力超級短暫的，大約只能維持2小時左右，所以我還是把比較複雜的概念記下來好了。



根據Wikipedia(http://en.wikipedia.org/wiki/Linear)的解釋(我覺得東查一點西查一點只會弄得觀念一團亂，最後還是看wikipedia整理得最好)：

Independent linearity is probably the most commonly-used linearity definition and is often found in the specifications for DMMs and ADCs, as well as devices like potentiometers. Independent linearity is defined as the maximum deviation of actual performance relative to a straight line, located such that it minimizes the maximum deviation. In that case there are no constraints placed upon the positioning of the straight line and it may be wherever necessary to minimize the deviations between it and the device's actual performance characteristic.

獨立線性(independent linearity)就是從測量出來的數據，來拉出那條直線，那條直線的位置不固定，以讓線性誤差值最小為主，這是最常用的線性定義，所以一般比如說要做到線性1%，指的應該都是獨立線性，偏偏我們送去日本某大車廠承認的PCB印刷板卻無法通過，原來他們用的是更嚴格的絕對線性(Absolute linearity)

absolute linearity, is sometimes also encountered. Absolute linearity is a variation of terminal linearity, in that it allows no flexibility in the placement of the straight line, however in this case the gain and offset errors of the actual device are included in the linearity measurement, making this the most difficult measure of a device's performance. For absolute linearity the end points of the straight line are defined by the ideal upper and lower range values for the device, rather than the actual values. The linearity error in this instance is the maximum deviation of the actual device's performance from ideal.

絕對線性就沒那麼好說話了，基準線就照理論值畫，起點跟終點都不能亂跑，測出來的數據跟這條理想線的最大的誤差值就是絕對線性值。

弄清楚後發現其實是很簡單的道理，可是問了幾個人都講得不清不楚的，看來有時候還是要自己上網做做功課…