[sdiy] Basic core designs of commercial analogs

[jhaible]

>> What I really recommend is the thru-zero FM (also "scaled"), because
>> this is where linear FM starts to sound interesting IMO. But I don't
>> have a circuit to do this glitch free, either.
>
>How do you do that then? It was some time since I last spent the little
>grey on the matter...

There should be a CEM3340-based circuit on my homepage for
thru-zero FM. It works, but it's not glitch-free when you approach
thru zero mode. Fairly nice with rather high modulation index, fairly
nice with low modulation index, but the transition is not glitch-free.

JH.