[sdiy] Buchla 295 10-band comb filter topology

[brianw]

On Nov 25, 2022, at 4:52 PM, Mike Bryant <mbryant at futurehorizons.com> wrote:
> > A quick visit to Wikipedia says that PM does not alter the frequency
> 
> I think this shows the wisdom of consulting a proper text book.  PM can alter the frequency but at the rate of change of the phase modulation rather than at the rate of the modulation itself.  Thus it's a first derivative effect.
> 
> If the modulation is a sine wave, then PM is actually a cos wave and produces the same output signal.

Thanks, Mike!

While pondering and writing, I was just starting to have a hunch that this is derivative (or integral?) related.

So, are you saying that Chowning isn't wrong? If the DX-7 is pure sine wave, then it seems like it doesn't really matter whether you call it FM or PM. Eh?

Brian

p.s. I have a number of textbooks, but few authors can translate the math into a language that makes sense. Hal Chamberlin is the best at this. Craig Anderton has a similar gift, coming from a different vantage. Steven W. Smith is one of the few to author a textbook, per se, that's understandable (by this engineer). Conversation works far more often than cracking a textbook, so I seriously appreciate your response as well as the others in this thread.