AW: VC delay module ideas?

[Sean Costello]

Haible Juergen wrote:

> Is there a way to add a few "discreet" buckets at the end of
> BBD line, and building a simple z-plane filter by weighting
> these different tabs with different resistors?
> I mean no doubt that it works in theory, but is there a simple
> practical way to do this ? How would these discreet buckets
> look like ? How many of them do I need for a reasonable
> FIR filter ? Is this special BBD chip with separate outputs
> any good here (I guess not) ?
> Any ideas ?

My guess is that you could use a sample and hold stage for each "bucket"
for the FIR filter.  I don't know how many unit delay stages you need,
but having each stage implemented as a sample-and-hold, clocked with the
same type of clock that drives a BBD delay, would probably do the job. I
know they used to make analog chips that had 32 tapped BBD stages for
this sort of filtering, but I would guess that DSPs replaced these
specialized chips a long time ago.

Sean Costello