[Hpsdr] Call for Comments - ALEX

[Rob Frohne]

HI Graham,

Thanks for the work on the filters. 

I note you are using some Chebyshev 5th and 7th order filters, and
cascading some of those.  Have you done any sensitivity analysis on
these?  Chebyshev filters can sometimes require fairly high Q
components, and more exact values.  

73,

Rob, KL7NA  

On Tue, 2007-07-24 at 20:49 -0500, Graham Haddock wrote:
> ***** High Performance Software Defined Radio Discussion List *****
> 
> All:
> 
> Well, the refelector seems so quiet that people are sending
> themselves test messages to make sure it is still working. 
> 
> For those who need something to do, I have a "call for
> comments" on ALEX.  All the information has been posted on the
> updated ALEX Wiki page. 
> 
> http://hpsdr.org/wiki/index.php?title=ALEXIARES
> 
> Please review the Wiki page for the overview, and if you want
> to dig deeper, download the three ".pdf" documents at the
> bottom of the Wiki page. One is the overall ALEX package, and
> one each for the filter simulations for the two filter boards.
> 
> The ALEX project has evolved to the description as now
> presented. I would like comments before we finish the PCB
> layout for first prototype units.
> 
> 
> Comments solicited:
> 
> Too many external (BNC) connections?  Or not enough?
> 
> Would you be willing to assemble this yourself, as opposed to
> purchasing a manufactured module?  It is a mix of through-hole
> and some surface mount components, and will also require some
> mechanical assembly.  It is not the kind of assembly
> that most contract manufacturers are used to dealing
> with.  I could limit the surface mount
> components to larger pitch ICs and larger passives.
> 
> There are about 20 ea. T-50 toroids and 5 wire coils that will
> need to be wound.  Would you prefer a kit of pre-wound toroids?
> Or would you rather wind them yourself?
> 
> Any concerns or alternative ideas you might have.
> 
> --- Graham / KE9H
> 
> ==
> 
> 
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-- 
Rob Frohne, Ph.D., P.E., Professor
E.F. Cross School of Engineering
Walla Walla College
100 SW 4th St.
College Place, WA 99324
(509) 527-2075
http://www.wwc.edu/~frohro/


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