> > While the effect on the output spectrum is that of a
> bandpass filter, I
> > don't think NR works that way.
NR works in a variety of ways, including using LMS or some other adaption
algorithm to adapt the coefficients of an IIR or FIR filter, in the classic
Wiener filter noise reduction algorithm. And the spectral response of the
filter does indeed consist of multiple relative peaks in the passband,
corresponding one hopes with the primary spectral components of the signal.
Do I know that's what's in the Orion? No. I suspect on one else on the
sidelines does for sure either, and those that know aren't really talking.
Is it a Linear Predictor, as someone has suggested? For what it's worth, a
Linear Predictor can be used, again, in Wiener noise filtering, to provide
an estimate of the signal spectrum. Or is it correlation (or auto), based
on DFT spectral estimation, or something else. There are as many ways to do
this as there are chapters in a book, and the more processing power
available to do it the merrier.
If one sees what appears to be a bandpass filter on a spectrum analyser,
what else is it, regardless of the underlying alogrithm? If it walks like a
duck ....
But I fear we're all just talking at, instead of with, each other at this
point. Perhaps we should settle on a common text reference? :-)
Grant/NQ5T
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