Hi Andy
Try a 'Linear Feedback Shift Register', Google it...
Very simple to implement in a MCU and can be scaled to any size you
like. I wrote some code to do this in PIC assembly years ago that was
only a few lines long for a 256bit sequence...
Best of all you can predict the outcome and choose a sequence that meets
your needs given a unique seed word....
Better yet it offers a means of identification over a long term
integration :-)
73 Scott
VE7TIL
Andy Talbot wrote:
...but if any mathematicians, number theorists or cryptographers
should be reading this...
I've just got a WSPR generating routine running on a PIC / AD9852 /
GPS combination, but I'm looking for a half-decent way of generating a
pseudo random Tx/Rx sequence with defined duty cycle that does not
give the long(ish) consecutive runs of 0's or 1's that MUST ALWAYS
occasionally be seen in a truly random sequence.
In other words, the sequence needs to be bandpass filtered.
Before I cop-out and just use a pre-generated set of lookup tables,
take a look at http://www.g4jnt.com/WSPR_PN_Sequence.pdf
for a fuller description of the mind-bender
Andy G4JNT
www.g4jnt.com
| 