0. If you have an RF signal whose waveform is , the amplitude is constant and 1.
1. If the waveform , the amplitude has the DC value of 1 and AM with the amplitude of 0.1 (i.e. swing is from 0.9 to 1.1). Therefore the RMS RIN of this signal is 0.1/1/Sqrt(2).
2. The above waveform can be expanded by the exponentials.
Therefore the sideband carrier ratio R is 0.025/0.5 = 0.05. This corresponds to 20 log10(0.05) = -26dBc
In total, we get the relationship of dBc and RIN as , or R = RIN/sqrt(2)