[hpsdr] Demeter: Modularity

[Jeroen Bastemeijer]

Hello Henry,

Thank you for your input to the Demeter project. Thank you for the input 
you provided to my personal address as well. I will compile all the new 
input, form all the contributers, to a new document. Hope to post it soon.

Mr. Bakker, thank you for the interesting link to the LT application 
note. The appendices might be even more interesting than the real 
article... ;-)

73 Jeroen

Henry Vredegoor wrote:

>***** High Performance Software Defined Radio Discussion List *****
>
>  
>
>
> ------------------------------------------------------------------------
>
> Hello Jeroen, All,
>  
> As to the question of if there should be a number of smaller boards or 
> one (or two) bigger boards, I think it would be the best option if we 
> want optimal flexibility and scalability.
> On the other hand a single board with all the different regulators and 
> control processor on it has the advantages of being compact and 
> the easier interconnections between them.
>  
> I don't know what the aim is for the upper limit of the 
> currents/voltages/power for the different regulators planned for 
> Demeter and the resulting total dissipation that goes with these.
> I could imagine that you would like to dissipate the heat to the 
> outside of the HPSDR enclosure using external heatsinks (avoiding 
> noisy ventilators)
>  
> All that said. a number of questions/remarks that come to mind:
>  
>  - Will these boards have external power devices that need to be 
> mounted off-board (e.g. the linear regulators)?
>  - Could one scale up for more current? (more power devices etc.), 
> What about regulators in parallel for higher current?
>  - Could one add more voltages (regulators)? 
>  - Would separate boards give more options for EMI suppression 
> (earthing, shielding, mechanical) ?
>  - Mechanical mounting
>    -  Attached with their power devices directly to an (external) 
> heatsink?
>      Running longer wires to an external  power device on a heatsink 
> is not a good idea, especially not for a switcher... ;-)
>    - Have a particular regulator as close as possible to the attached 
> user (e.g. a power amp)?
>  - Scalability:
>     - With a linear regulator it is relatively easy to increase the 
> output current; you could have a low power board for a limited current 
> and scale up by adding external power devices
>     - This is not the case with a switching regulator as far as I know.
>       This would require besides adding a more high power switcher 
> device also at least exchanging inductors and capacitors with higher 
> power versions and other C and L values?
>  
> I think some of these aspects are good reasons to have regulator 
> board(s) to be separate ones?
>  
> I am aware of the fact that this makes the internal wiring more 
> difficult though..
>  
> The PSU controller board containing the microcontroller I think should 
> be a separate board anyway.
> That could even be on ATLAS for easy connection to backplane signals 
> for e.g. voltage monitoring, Power Good signal etc.?
>  
> So I think the answer for me in general would be "YES!!"
>  
>  
> 73's,
>  
> Henry.
>
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-- 
Ing. Jeroen Bastemeijer

Delft University of Technology
Department of Electrical Engineering
Electronic Instrumentation Laboratory
Mekelweg 4, Room 13.090
2628 CD Delft
The Netherlands

Phone: +31.15.27.86542
Fax: +31.15.27.85755
E-mail: J.Bastemeijer at TUDelft.nl
GPS: Lat N52.00002 Lon E4.37157 Alt 46.2m

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