# Is it true that frequency deviation over 2*pi is the phase deviation of an FM/PM signal?

for ∆f frequency deviation if for FM only and PM has Phase deviation. and Kf= ∆f (Hz) of FM? Kf = ∆f (rad/s) for PM? and for th rules:

∆f=(kfmp)/(2p) for FM where mp = mp max-mp min ∆f=(kfmp)/(2p) for PM where mp' =mp'max-mp'min

does this rule apply for frequency deviation of the carrier and the former of Kf and Kp is for the frequency deviation of the message signal?

and do if it is correct that PM has frequency deviation, does FM has phase deviation?

I am so confused and some one clarify me this concept.

The modulation index at a single modulation frequency is $\frac{FrequencyDeviation}{ModulationFrequency}$