I have make a FSK with a tiny 25,
F1= 110Khz , F2 = 114Khz ( chrystal 14,14MHz),
signal square 1Khz
but I see strange on the spectrum ( no picture ) make test in the customer lab.
spectrum will have in teori on carrier to 110K on to 114K ,
in pratic you have 112K too.
Testing to send only one carrier to control SW value and each frequency are rigth.
when I make the modulation I get a carrier frequency value moved a few KHz ( no remember the exact value)
I get Carrier F1 & carrier F2 ( with another value some KHz difference) and a lot of harmonique.
I get some small carrier at 111K & 113KHz ?
Is it a way to reduce harmonique with SW ? ( I write it because see at if you do not synchro the frequency change you make a lot of noise)
Why my carrier F1 & F2 has change?
I guess the harmonique is because my carrier is square and the customer has no filter on the RF power stage .
the 111K & 113KHz it is a "effect of digital spectrum"?
Customer has a USB digital spectrum analyser. I have not a spectrum som work i the frequency.
Thank you for a teori update on FSK.