Thanks! That's pretty much what I had decided... except all the
LFSR/PRBS pages are all confusing as hell to an Analog guy :-)

It will click when you see it. The key idea is Finite State Machine.
With N flip-flops, the best you can do is 2^N states. A counter
gets them all, but it's not random.

A LFSR with the right taps gets 2^N-1, and they happen to be a
"nice" random pattern. They are widely used in gear for testing
communication links.



Horowitz and Hill, Art of Electronics, has a nice section starting
on page 655. It's only 3 pages, no hairy math.

The Wikipedia article on LFSRs is good:
http://en.wikipedia.org/wiki/Linear_...shift_register

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