On Fri, 2005-09-16 at 04:41 +0100, Lee Elliott wrote:
> Hello List,
>
> I think there's a small bug in the moving-average filter in
...
> xmlauto.cxx
> else if (filterType == movingAverage)
> {
> output.push_front(output[0] +
> (input[0] - input.back()) /
> (samples - 1));
> unsigned int i;
> for ( i = 0; i < output_list.size(); ++i ) {
> output_list[i]->setDoubleValue( output[0] );
> }
> output.resize(1);
> }
I'm not trying to flame, but why would you be using a moving average
filter? That's the most complicated filter I've ever seen - it calls
other functions! I always liked the simplicity of a low pass filter:
output += (measurement - output) * gain;
Using floats, doubles, or fixed point of course.
No need to call a function either, just in-line it where you need it.
Want fast convergence on startup? Just sweep the gain from 1.0 down to
whatever the steady state value needs to be. I bet this is nothing new -
it's probably in the code under "else if (filterType == IIRfilter)" or
something.
So why do people use moving average filters? Why does FGFS?
Thanks,
Paul
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