To use CEM or not.

[Andrew Schrock]

On Tue, 21 Sep 1999 thudson at cygnus.com wrote:
> Paul Schreiber wrote:
> >
> > Here is the chip I wish I could get rid of, as I have OVER 10,000!!!
> > 
> > CEM3320 Filter/quad OTA
> >
> Isn't this the one Thomas Henry used in the PAL filter? It features
> switchable phasor/all pass/low pass responses. I didn't realize you
> had so many, and at only $10 each... Perhaps someone could make a
> run of boards. Eight would be a good companion to a Shepard Function
> generator.

Ok, here's a question for the group: The Paia EKx-20 CEM 3320 filter has a
little 8-pin header which you can re-wire for different configurations.
(all-pass, HP, LP, or BP) If you just look at the application notes for
the 3320 you'll see approximately how the different stages could be
switched.. but it requires more than just one switch. Not easily
configurable for switching easily via a SPDT or SPST switch. 

What I want is simple: to be able to switch HP/LP/BP from the front panel.
Anybody have ideas? A series of analog gates? Weird rotary switch I
haven't heard of yet? (I would rather not buy another 3320) 

later
Andrew

-| Andrew Schrock | aschrock at cs.brandeis.edu |-