For error analysis, it’s hip to be squared

I’m going to deviate from my normal coverage of modular instruments and alternative testing techniques, and focus on an associated design and test issue: error analysis.

Almost all analog designs require an error analysis. Components are not ideal; they all vary with regards to their specifications. Those variations add up in interesting ways.

I was deeply involved in error analysis when I was an analog engineer in the late 1970s and early 1980s.  Though Huey Lewis and the News hadn’t formed yet, that’s when I learned that it is hip to be squared.

What do I mean by that?

Basically, we choose components, each around a nominal value, to create a design. Lots of components. To statistically compute error bands of the entire design, I squared the possible error due to each component, summed them all up, and took the square root of the total. That would be error limit of the entire design. This is also known as RSS: Root of the Sum of the Squares. You can use RSS as a verb too, “I RSS’d the errors together.”

Why do I do that? Read the entire article here.

By Larry DJ

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