[time-nuts] Digital Mixing with a BeagleBone Black and D Flip Flop

Anders Wallin anders.e.e.wallin at gmail.com
Tue Oct 14 12:14:16 EDT 2014


two D-flops in series make a synchronizer!? (see the input-channels on
Nutt-type time interval counters)
http://chipdesignmag.com/print.php?articleId=32?issueId=5
you've lost all your noise - but you've also got rid of all the signal - so
not great for improving SNR.

On Tue, Oct 14, 2014 at 6:32 PM, Simon Marsh <subscriptions at burble.com>
wrote:
>
> I now have the 2 D-flops in a 74AC74 wired in series so that one does the
> sampling and the other acts as a shift register before the output is sent
> on to the BBB.
> I got so far with this before realising that one of the D-flops was being
> much more noisy than the other and indeed it was only a single output that
> was particularly noisy. Switching to the inverted output reduced the noise
> considerably.
> After a bit of head scratching I swapped the part with the result that
> _all_ the glitches vanished. Completely. Even at small beat frequencies
> (<5hz).
>



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