Error Analysis / Calculation Excel Spreadsheet - by Michael Maguire
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Thanks once again to RF Cafe visitor Michael Maguire for providing yet another useful spreadsheet†, this one for calculating errors (Error Analysis) in various sorts of combinations of numbers. It also handily includes an ability to calculate errors when converting between linear and decibel values - which is useful when performing cascade analysis.

As you might recall from your statistics and probabilities or error analysis class, errors propagate through a system according to how serial and parallel elements are combined from input to output. Calculation can be as simple as linear addition of individual elemental errors to more complex calculations when multiplication, division, and exponentiation are involved.

If I recall correctly, my introduction to formal error analysis was in a math course of that name in the Fall semester of my sophomore year of engineering school. It was a prerequisite to taking Physics II, Chemistry II, and Statistics and Dynamics classes because laboratory write-ups required that error analysis be performed on all our projects from that point forward. That was sometime around 1985. The textbook was the one shown in the thumbnail here, and is quite memorable because of the cover image of a train having broken through the wall of a roundhouse due to, implicitly, an error in judgment, which is in reality difficult to objectively quantify.

The screenshots provided here of Michael's Error Analysis spreadsheet give you a good idea of the usefulness of his work. Click this link to download a free ZIPed copy of the Error Analysis spreadsheet.

Hint: I like to lock the equation cells to prevent accidently overwriting them. An even better thing to do is to protect all cells except the "Data Entry Field" cells (bluish-gray) against being accidentally changed. To do so, select all the "Data Entry Field" cells by clicking in them while holding down the Ctrl key. Right-click and select "Format cells..." from the sub-menu, select the "Protection" tab, and uncheck the "Locked" box, then "OK." Finally, go to the main menu "Review" tab and click on "Protect Sheet." Click OK without changing any of the default settings (only enter a password if you need one; otherwise, leave it unchecked). To check the lock, click in an empty cell and hit the "Del" key. You should get warning about attempting to change a protected cell. Unprotect everything by doing "Review" and "Unprotect Sheet."

† See also CNES RF Propagation Calculations DLL

Posted July 26, 2022