floating inductor simulation?

[Don Tillman]

   From: Haible_Juergen
   Date: Wed, 29 Nov 95 10:50:00 PST

   For an emulation of the Hammond Vibrato, I need a lot of Inductors
   in the 500mH range.

You're one very busy guy!

   I thought about building them with gyrators, but I don't have
   the right circuit so far.

Now let me get this straight; relays are reasonable and inductors are
not. :-)

   I know that simulating a *grounded* inductor is quite
   easy - done it many times for EQ circuits with the simple
   one-opamp circuit that has some parasitic effects.

   Now for the *floating* inductors that I need, I only know
   a circuit with 2 gyrators. It uses 4 opamps and many
   resistors, and I wonder if there is another way to to it!

I wouldn't recommend using a gyrator. Instead I'd build little active
filter units for each stage of the chain that duplicate each LC
transfer function....

...No, wait a second, that's not good enough, there's important
interaction between the stages.

I have to think about this a little more.  

(I know about that 4 opamp gyrator circuit, but I don't know of
anything simpler.  Hmmm, maybe with OTAs?)

  -- Don