# A Note on Polynomial Fitting

In This Posting, I wrote that Polynomial Smoothing / Fitting / Approximation can be used in conjunction with a Sinc Filter, to convert Sample-Rates. I should note that sometimes, Polynomial functions can be used by themselves.

This could be an explanation for how early CD Players eventually replaced the sinc filter, with “Mathematical Sound Shaping” (M.A.S.H.). The sinc filters were much maligned for their lack of immediacy. In their place, M.A.S.H. suffered from some level of distortion at frequencies near the Nyquist Frequency.

Further, experiments I have yet to carry out with ‘QTractor‘, may show, that it will convert

44.1 kHz -> 48 kHz

using the exact same method as

48 kHz -> 44.1 kHz

Assuming that is, I set the Global filtering method to a (slower) non-default setting.

Dirk