I've written PIC code to decode a serial 12 bit word received via a radio
module.

My problem is noise - I'm decoding the signal by looking for a start bit
of 2ms high, then sampling in the middle of the data bit, then
re-synchronising on the start of the next data bit by waiting for the
signal to go high

Unfortunately, if there is a noise spike in the middle of all this I see
it as a state change and lose synchronisation.

Anyone got advice on how signals of this sort are best processed - am I
approaching this from the wrong direction - should I be measuring the
length of each pulse and throwing away anything shorter than a data bit?

Your help would be appreciated
Neil Strong
Neil.Strong@syntegra.bt.co.uk