[sdiy] Looking for help with Bessel functions and FM

[Czech Martin]

The proposed texts are all o.k.

But you should also read a basic text from the kind
of people that invented FM, i.e. communications engineers
and maybe also radio amateur texts. Because these texts
will often have a cleaner and more thorough math
part, e.g. in the relation between phase and frequency
and consequently in the relation between phase and frequency
modulation , which is especially important if the modulator
is NOT sine shaped (as it will nearly always be with more than
one modulator stacked).

OTOH the case of strong (wide band) modulation and through
zero modulation is often not
covered in these texts (naturally), this is where the more
"musical texts" are better.

It often looks like this:

                       Music              Radio
basics + bessel          x                  x
diff.ce phase frequ.     0                  x
wideband                 x                  0
non sine modulator       0                  x
through zero             x                  0
----------------------------------------------
                         3                  3

So you need both.
The good think is that amateur radio people have a lot of
education texts in the web, just google.

m.c.

-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Glen
Sent: 22 August 2004 18:56
To: synth-diy at dropmix.xs4all.nl
Subject: [sdiy] Looking for help with Bessel functions and FM


I have a pet project that I'd like to get started on. I would like to
analyze an FM synthesizer patch and calculate the theoretical output
spectrum that would exist any given moment when playing one note using that
patch. What I would like to eventually do with that ability is translate an
FM synth patch into an additive synth patch.

I think Bessel functions are something I need to learn about for this
project, but I'm having trouble finding enough information, especially in a
format that I can understand. Does anyone know of any good FM modulation
and/or Bessel function tutorials?

thanks,
Glen