Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hpl-opus!hpnmdla!hpsad!toma From: toma@hpsad.HP.COM (Tom Anderson) Newsgroups: comp.dsp Subject: Re: Re: Pitch shift / offset and FFT Message-ID: <9520003@hpsad.HP.COM> Date: 28 Sep 89 19:12:58 GMT References: <4384@internal.Apple.COM> Organization: HP Signal Analysis Division - Rohnert Park, CA Lines: 16 > Taking the real part of both sides: I don't know much about ears, but I believe that they hear: sqrt(Real_part^2+Imaginary_part^2) and so it is incorrect to just look at the real part. Also, if you look at two tones on a spectrum analyzer, you just see two tones and no beat notes in a linear system. (I just tried this to make sure :-)). It takes a nonlinearity to generate the "mixing products" in the frequency domain. Tom Anderson "It's only hardware" Hewlett-Packard Signal Analysis Division Opinions expressed are my own and not HP's.