Re: PCB power planes?

John Larkin wrote:
On 8 Jul 2008 13:27:47 GMT, Scott Seidman
<namdiesttocs@xxxxxxxxxxxxxx> wrote:

Joerg <notthisjoergsch@xxxxxxxxxxxxxxxxxxxxx> wrote in news:iUvck.14888
$N87.12030@xxxxxxxxxxxxxxxxxxxx:

That would be way out of league for most of my designs.

It depends on how much you need a tunable filter, and how good you need it to be.

I used to use a bank of these: http://www.tucker.com/java/jsp/product_partno3202R_invid9608_condR.htm

At $500 per channel used for a 4-pole tunable filter, 4 bucks a channel for digital pots plus the UAF42 is quite a bargain. Of course, you need to build your serial bus and then write some code to support it, but still the bargain.

Sure you can make your own, but it will be 20 times the size, and 2x
the cost, of the DDS chip or dac you're trying to post-filter. And
past a couple of MHz it will be difficult.


I find things to be easier past a couple of MHz because there you can use inductors and PIN diodes. Ok, depends on what your home turf is. Active filters aren't mine but MHz stuff is.

--
Regards, Joerg

http://www.analogconsultants.com/

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Relevant Pages

  • Re: PCB power planes?
    ... On 8 Jul 2008 13:27:47 GMT, Scott Seidman ... It depends on how much you need a tunable filter, and how good you need it ... digital pots plus the UAF42 is quite a bargain. ... of the DDS chip or dac you're trying to post-filter. ...
    (sci.electronics.design)
  • Re: PCB power planes?
    ... It depends on how much you need a tunable filter, and how good you need it ... I used to use a bank of these: ... digital pots plus the UAF42 is quite a bargain. ... Reverse name to reply ...
    (sci.electronics.design)
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