Dictionary of Electrical Engineering

Commonly used terms in the Electrical industry.

ratio of the signal power (p) to a reference signal power (pref), usually the modulation carrier signal, expressed in decibels referenced to a carrier (dBc). Thus a harmonic signal that is 1/100th of the power in a desired fundamental signal is at -20 dBc.

PdBd = 10 log10 ( p / pref )