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

Original Message Subject: Re: [music-dsp] � 45� Hilbert transformer using pair of IIR APFs From: "Eric Brombaugh" Date: Sun, February 5, 2017 8:22 pm To: "A discussion list for music-related DSP"

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

On Feb 5, 2017, at 12:54 PM, robert bristow-johnson wrote: > using the analytic filter to get the instantaneous amplitude envelope (and, > also, instantaneous frequency by differentiating phase) is something that > works only with single sinusoids that are AM'd or FM'd. for music, i think i

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

Original Message Subject: Re: [music-dsp] � 45� Hilbert transformer using pair of IIR APFs From: "Ethan Fenn" Date: Sun, February 5, 2017 1:39 pm To: music-dsp@music.columbia.edu

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

Some very interesting references. I'm curious what uses people find for the Hilbert transform for in audio. An instantaneous amplitude envelope, for use in compressors and other envelope-driven effects? Or something else? -Ethan On Sun, Feb 5, 2017 at 10:13 AM, Eric Brombaugh

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

Yes, I'm using the Hilbert transform to generate an analytic signal for use in a Bode-style frequency shifter and also in single-sideband modulator and demodulators. The image rejection metric is a critical aspect of the performance of these systems and is related to the error from true 90deg

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

typofix: "and their companion poles" -> "and their companion zeros" -olli On Sun, Feb 5, 2017 at 1:52 PM, Olli Niemitalo wrote: > 90 deg phase difference all-pass filter pairs... Lemme wave my hands a bit: > > It's been years, but I recall I first tried a structure with complex >

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

90 deg phase difference all-pass filter pairs... Lemme wave my hands a bit: It's been years, but I recall I first tried a structure with complex conjugate pairs of poles (and their companion poles to make the filters all-pass). Globally optimizing that using Differential Evolution, the poles

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

robert bristow-johnson wrote: cool, so it appears from your comments to be real poles. complex conjugate poles are not considered in the design. i wonder why that is? I’m not the author of the formula, I just implemented it and don’t understand how it produces these filters. I guess the

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

� cool, so it appears from your comments to be real poles. �complex conjugate poles are not considered in the design. �i wonder why that is? r b-j Original Message Subject: Re: [music-dsp] � 45� Hilbert transformer using pair of IIR

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

robert bristow-johnson wrote: so Olli, how do you get your coefficients? (if i may ask?) If I may reply, I wrote long time ago a C++ library implementing this kind of polyphase halfband filter, including a coefficient calculator involving elliptic stuff (way beyond my knowledge). Check the