[hpsdr] Power supply issue

[Jeroen Bastemeijer]

Dear All,

Unfortunately I do not have time to really develop boards or circuits. 
But I was just thinking about the whole project as things  are getting 
really exciting with the boards being really produced now.

There have been some discussions about the power supply. One point we 
have missed (or I missed the E-mail dealing with this subject) is the 
standby requirement for the power supply and the reset features of all 
the boards.

All this was triggered by some thoughts on the Gibraltar board. This 
board should provide rock-stable signals for the whole project. To 
achieve high stability it seems the most logical to keep the 
(main)oscillator and the GPS-receiver alive, even when the rest of the 
HPSDR is switched of. This could be achieved by using one power supply 
and switch off each individual module (e.g. using FETs in the supply 
rails) or using a separate power supply for the Gibraltar.
Switching of each separate module is not an option anymore as some 
boards are already made and the atlas doesn't provide this 
functionality. So a separate standby power supply (maybe with battery 
back-up) will be needed for the Girbraltar. A simple linear power supply 
will be the best and most reliable (not sensitive to e.g. brown-outs).

Furthermore, is there any idea about the resetting of a specific card? 
E.g. when one card "hangs" and needs a reset the whole system keeps 
running in its current state only the card with the problem can be 
reset. With Gibraltar in mind, a reset would mean loss of GPS-tracking 
and cause a temporary frequency shift.

Just some thoughts.... hopefully worth a penny.

73's Jeroen PE1RGE

-- 
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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