Hello,
We are using the SPIRIT1 with a 50MHz crystal (as part of an SPSGRFC-433 module); I've configured it to MSK, with a base frequency of 433.175MHz, a data rate of 250kBaud, which leads to a configured frequency deviation of ±62.5kHz. I've set a bandwidth of 125kHz, but a channel spacing of 248.718kHz. FEC is switched off, with data whitening switched on.
Initially, things look good: transmitting an unmodulated carrier shows a nice, sharp spike at the right place on a spectrum analyser. If I then send packets, the spectrum looks sort of correct, in the sense that there is a spike either side of the base frequency.
But, the the two spikes seem to have double the frequency division I've configured (i.e. ±125kHz).
What might I be doing wrong? Or am I misunderstanding something?
Many thanks,
Andrew.
