In Chamber Testing

[vex]

Originally Posted by Barry Bordes

Barry

Windowing occurs when you sample something too slowly and the result is a different reading altogether. For instance say you take a sample of a simple sine wave with a frequency (i'll keep it simple) of 4khz. If you sample that same sine wave at some other frequency that is less than 4khz you could get some surprizing results. Windowing would occur and you may end up looking at a cosine wave with a frequency of 2.3khz and a different amplitude that fluctuates over time. Not exactly what you're looking at? For DAQ's it is a good rule of thumb to sample at twice the frequency than what your expecting to be as your function. IE: if you are ever going to see 48khz in a function you'd want to sample double that to ensure you don't have window the function.

There is also another windowing occurance which usually helps in DAQ systems and is fairly easily explained in the following wiki article:
http://en.wikipedia.org/wiki/Window_function