Re: [music-dsp] ± 45° Hilbert transformer using pair of IIR APFs

2017-02-09 Thread Ethan Duni
> how do you quadrature modulate without Hilbert filters? > Perhaps I'm using the wrong term - the operation in question is just the multiplication of a signal by e^jwn. Or, equivalently, multiplying the real part by cos(wn) and the imaginary part by sin(wn) - a pair of "quadrature oscillators."

Re: [music-dsp] ± 45° Hilbert transformer using pair of IIR APFs

2017-02-09 Thread robert bristow-johnson
Original Message Subject: Re: [music-dsp] � 45� Hilbert transformer using pair of IIR APFs From: "Ethan Duni" Date: Thu, February 9, 2017 5:06 pm To: "A discussion list for music-related DSP"

Re: [music-dsp] ± 45° Hilbert transformer using pair of IIR APFs

2017-02-09 Thread Ethan Duni
On Tue, Feb 7, 2017 at 6:49 AM, Ethan Fenn wrote: > So I guess the general idea with these frequency shifters is something > like: > > pre-filter -> generate Hilbert pair -> multiply by e^iwt -> take the real > part > > Am I getting that right? > Exactly, this is a

Re: [music-dsp] ± 45° Hilbert transformer for pitch detection?

2017-02-09 Thread Evan Balster
That jitter, eh? https://en.wikipedia.org/wiki/Kalman_filter Your algorithm won't work for general pitch sources, become many in the wild will lack a prominent fundamental frequency. That said, it's pretty fun and some good creative mischief might be had with it. For example, try multiplying a

Re: [music-dsp] ± 45° Hilbert transformer for pitch detection?

2017-02-09 Thread gm
Here is another test with more difficult input Also works an drums, kind of https://soundcloud.com/magnetic_winter/adaptive-ap-pitchtrack-2/s-FCoKI ___ dupswapdrop: music-dsp mailing list music-dsp@music.columbia.edu

Re: [music-dsp] ± 45° Hilbert transformer using pair of IIR APFs

2017-02-09 Thread gm
Am 09.02.2017 um 14:15 schrieb Theo Verelst: The idea of estimating a single sine wave frequency, amplitude and phase with a short and easy as possible filter appeals to me though. Did you listen to the example I posted? Do you think it's useful? Or too many artefacts?

Re: [music-dsp] ± 45° Hilbert transformer using pair of IIR APFs

2017-02-09 Thread Sampo Syreeni
On 2017-02-07, Theo Verelst wrote: Like with many transforms, I can't help but practically think that it's hard to make a tradeoff between the meaning of the results, such as [...] Here there's an rather simple optimization criterion: a constant 45 degree phase offset, or perhaps a pair of

Re: [music-dsp] ± 45° Hilbert transformer using pair of IIR APFs

2017-02-09 Thread Theo Verelst
Thinking about it, I recall there was some from of transform used for frequency/time analysis for instance for radar problems (maybe books from before WWII, or more recent frequency/time analyzers) and without checking though it was in popular DSP speak something like the Hilbert transform, but

Re: [music-dsp] ± 45° Hilbert transformer using pair of IIR APFs

2017-02-09 Thread Sampo Syreeni
On 2017-02-06, robert bristow-johnson wrote: [...] and analytic signal      a(t)  =  x(t)  +  j y(t)            =  g(t) cos(w t)  +  j g(t) sin(w t)            =  g(t) e^(j w t) the analytic envelope is      |a(t)|  =  sqrt( x(t)^2  +  y(t)^2 )              =  g(t) so that works great for a