Are there other cases where people have used LFSR sequences rather
than counters?
I first ran into them for planetary missions. An LFSR has a -0
autocorrelation everywhere but within half-a-bit of synchronized, and
which point it ramps up to a huge autocorrelation when exactly
synchronized. Squeeze this witch hat enough (run a very long, very
fast sequence) and you get a nice spiky delta-function-like thing,
which means you can resolve small features with the return signal.
(it's the chipping version of what we were talking about with chirps)
_______________/\_______________/\_______________/\_______________/\
-Dave
(CDMA works because different codes won't interfere with each other as
long as they all control their gain well -- I don't know how that's
done, but maybe the side slopes on the correlation would allow a device
to make fine adjustments for how it's moving relative to the base?)
