[sdiy] Filter problem

[Neil Johnson]

Ian,

> Nice work. It's always good to see something original.

Thanks!

> I bought some of the SSM2164 chips a while ago but haven't had time to
> play with them. It looks as though the 470R/560p networks may be
> addressing my question about high frequency stability.

Well, the datasheet recommends 500R/560p, but I figure 470R is close
enough!  Also, quote from the datasheet:

    "Additionally, a 500R resistor in series with a 560 pF capacitor
    must be added from each input to ground to ensure stable operation."

> I wonder, did you try putting the D1/D2 limiters at different positions
> in the loop?

Not yet, I may look at that next week.  At the moment I'm happy that its
now stable, won't go wandering off into the weeds, and works over a range
that I want (upto about 24kHz, and down to almost-DC).

And now I've got to squeeze this onto 2"x2".  Trust me, its the challenge.
I'm not mad...

Neil

--
Neil Johnson :: Computer Laboratory :: University of Cambridge ::
http://www.njohnson.co.uk          http://www.cl.cam.ac.uk/~nej22
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