Difference between Preamble and Sync word (CC1101)

No answers? :-( Is it necessary to detect all the 1's and 0's of the Preamble to detect a valid packet? Or is it sufficient to detect a valid sync word (e.g. 15/16)?

Thanks a lot

The preamble is fixed as 1010101... with a length that can change.  The idea is that the recevier can "hear" this, and set the gain and everything correctly to actually decode the desired data and sync word.

I am most familiar with the CC1100E, and for it there is a "preamble threshold" that you can set that means x number of preable bits have to be detected to allow data to be read (it knows the data rate and counts the transistions adding one every time there is a 1 to 0 change in the data, and dropping the count by one if there is not a transistion).  This can be turned off, so so you can get away with no concern about the preamble other than to get the gain structure right for the receiver.

The sync word is chosen and not just 1010101... and this can also be ignored or a threshold set for how many bits are required to be correct to then receive.

The more checks you have, the better the chance that the transmitted packet is good enough to get through without error, but also the more overhead in transmitting.

Thank you very much!