[time-nuts] BBB DDMTD - analysis

Hal Murray hmurray at megapathdsl.net
Thu Oct 30 15:08:31 EDT 2014


subscriptions at burble.com said:
> In an effort to understand which component was responsible for my ~17us
> spikes ...

17 microseconds is 58 KHz.  That's a reasonable number for a switching power 
supply.

What does your power look like?

I don't know what you are using for a  circuit.  My guess is that the crap on 
the power is shifting the switching point slightly.  Note that both your 
scope and your BBB are digital sampling systems so you have opportunities for 
aliasing.

For the scope pictures, you have to consider 3 clocks.  The 3rd one is the 
clock in the scope.  My guess is that the fuzzy regions on your digital scope 
pictures are when the scope samples while the input signal is switching.

Do you (or a friend) have an analog scope?  It would be fun to set it up in 
parallel with the digital scope.



-- 
These are my opinions.  I hate spam.






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