[sdiy] Buchla 295 10-band comb filter topology

[Chris McDowell]

I'll add that the modulating waveform does not need to be the same frequency as, or an integer multiple of, the carrier waveform to qualify as phase modulation. PM refers to this implementation (chowning's, in this discussion) of what amounts to linear FM. It really is simply adding the output of one wavetable lookup to the accumulator of another. I -believe- (and I invite correction here) that the resulting harmonics are identical to those from linear frequency modulation. 

Chris McDowell 

> On Nov 26, 2022, at 1:31 PM, Donald Tillman <don at till.com> wrote:
> 
> 
>> 
>>> On Nov 25, 2022, at 4:15 PM, Neil Johnson <neil.johnson71 at gmail.com> wrote:
>>> 
>>> Donald Tillman wrote:
>>> This field has a rich history of goofing up the terminology.
>> 
>> Yup, same with Ring Modulator - even for devices with no diode ring, just VCAs!
> 
> Indeed.  Although I'm inclined to give that one a pass as it sounds so much like bell ringing.
> 
> The name "Phase Shifter" for the guitar effect makes it near impossible to describe how it works.
> 
> "The phase shifter is based around an all-pass filter."
> 
> "Wait... a what?  How can a filter pass everything?  That sounds like an oxymoron; like tight slacks."
> 
> "An all-pass filter does indeed pass the full spectrum, but it shifts the phase as a side effect."
> 
> "So it's a phase shifter?"
> 
> "Yes."
> 
> "So a phase shifter is based on a phase shifter?"
> 
>  -- Don
> --
> Donald Tillman, Palo Alto, California
> https://www.till.com
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