[PD] A 6th order hilbert transformer?

[katja]

Attached is a zip with test patch for [olli~] and [hilbert~] so you
can compare and also check with different sample rates. It seems that
Olli's coefficients are optimized to work well from 20 Hz up at 44K1
sample rate, and Pd's built-in from 80 Hz up. They both work at other
samples rates too, but with different range.

Since the coefficients for x[n-2] and y[n-2] are non-zero in the
biquads, the maximum phase shift  is as large as in any 2nd order
section, therefore I think the four sections together are 8 order
equivalent indeed.

By the way, the abstraction in my first response wasn't completely
vanilla-compatible, this is fixed in current attachment (for anyone
else interested).

Katja

On Thu, Jun 23, 2016 at 6:24 AM, Alexandre Torres Porres
<porres at gmail.com> wrote:
> Awesome, I can code it based on that :) but which order is it?
>
> I see it has 4 biquads, but it doesnt look like an 8th order because some
> coefficients are zeroed out, so I'm confused.
>
> Another question, does it work at any sample rate? This question is also
> aimed to pd's hilbert~ abstraction by the way.
>
> cheers
>
> 2016-06-22 17:27 GMT-03:00 katja <katjavetter at gmail.com>:
>>
>> Hi, Olli Niemitalou has coefficients published for a higher order
>> 'hilbert transformer' on http://yehar.com/blog/, attached is [olli~]
>> abstraction based on it.
>>
>> Katja
>>
>> On Wed, Jun 22, 2016 at 4:37 AM, Alexandre Torres Porres
>> <porres at gmail.com> wrote:
>> > Howdy, I'm working on a frequency shifter object (via single sideband
>> > modulation / complex modulation).
>> >
>> > In Max they have a so called "6th order hilbert transformer with a
>> > minimum
>> > of error". In Pd, the hilbert~ abstraction is 4th order. I'm copying the
>> > pd
>> > abstraction for now, but I was hoping to use such a higher order filter
>> > and
>> > also use- but I can't find a source for such a formula. Any help finding
>> > it?
>> >
>> > thanks
>> >
>> > _______________________________________________
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>
>
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