On 2013-02-08, Ivan Shmakov <oneing...@gmail.com> wrote: >>>>>> David Woolley <david@ex.djwhome.demon.invalid> writes: > > [Cross-posting, and setting Followup-To:, to news:comp.dsp.] > > [...] > > > In Fourier terms, the spectral width of a piano note is going to be > > more than 12ppm and depend on the exact interval over which you > > measure it. I would also suspect that the zero crossing interval > > changes significantly during the note, particularly at the start. > > As per my experience with guitar signals, such a waveform is > likely to cross zero more than once per period. Hence, by > counting such crossings one typically gets the frequency of one > of the note's harmonics, and not that of the pure tone. > > BTW, is there a kind of overview of a method that could allow > for frequency measurement for such a signal? (Preferably one > oriented to the uninitiated. I can probably handle complex > math, though.)
Use the fourier transform to get the rought freq. Then use zero crossings at around that period to narrow in on the freq. Of course if the harmonics are not exact (see piano) then those sero crossings will not give the freq of the fundamantal. You could filter the intput around that rough frequency of the fundamental, but that mightgive you very little signal ( the ear hears the fundamental pitch even if there is no fundamental i n the note ) > > TIA. > > [...] > _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
