dB is a “relative” difference between 2 measurements in dBm.
for example :
RxLev = -80dBm
When the signal increases by 3dB, the new RxLev is -77dBm.
CRO is an offset applied on the formula of C2.
C2 = rxlev – RXLEVACCESSMIN + CRO
rxlev-RXLEVACCESSMIN = dBm – dBm = dB
CRO is also in dB
C2 is in dB
C2 represents the difference of signals levels “rxlev” and “RXLEVACCESSMIN”, plus a certain offset.
dBm represents a received power :
0dBm = 1mW
-3dBm = 0.5mW
-6dBm = 0.25mW
dB is “relative” 🙂
look for other threads about this, you’ll find plenty.