C4FM

AcronymDefinition
C4FMConstant Envelope 4-Level Frequency Modulation
References in periodicals archive ?
C4FM modulation fidelity improvements: The compatible four-level frequency modulation (C4FM) fidelity meter on the IFR 2975 now reports the frequency error and deviation at symbol time in addition to the modulation fidelity error.
The 2975 quickly tests the transmitter performance of the radio in less than 20 seconds with quick visual indicators of power, frequency error and C4FM Error Vector Magnitude.