[sdiy] "FM" Synthesis (was Re: Buchla 295 10-band comb filter topology)

[Gordonjcp]

On Sun, Nov 27, 2022 at 03:56:03PM -0500, Matthew Skala via Synth-diy wrote:
> 
> In radio work, your FM signal is an FM signal regardless of whether you
> modulate the oscillator (which oscillator? - there may be three or more in
> a superhet transmitter, none of them operating at the final transmission
> frequency) or pass part of the signal at some point through a modulator
> that variably shifts the phase to create the modulation.  What matters is
> the signal itself.

In any decent FM exciter you modulate both the VCO and the crystal oscillator that the PLL locks to, exactly so you don't get phase modulation ;-)

I was always a big fan of those old Motorola MC Micros, even if they were a pain in the tits to set up.

-- 
Gordonjcp