11Digital filters

11.1Why digital?

As a kid, I opened my tape-recorder (hopefully you have at least heard about these things). Inside it, was a lot of small things that could be turned with a screwdriver. I turned them all, but it didn’t really improve. Later I learned that these “potentiometers” compensated for all the components that were not exactly the specified value. Somewhere at a production-site, someone had manually adjusted each of these. A lot of work. Unfortunately, due to aging of the components, this calibration ought to be done at regular intervals. And indeed professional measurement institutions are carefully marking their equipment with “next calibration date.”

As embedded software developers, we tend to see the world as being ...

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