If I use vco max2606 as an fm modulator with frequency sensitivity 10MHz, modulation signal 2.5KHz added to DC tuning V, and Fcarrier = 105MHz.
How do I find requested RMS voltage of modulating signal?
Tanx

 

If you really only want the RMS of the 2.5kHz modulating signal

Vmod_2.5kHz_rms=Vrms_2.5kHz_component

So if the 2.5kHz signal is a sinusoid of peak magnitude Vm, then its RMS is Vm/√2.

Perhaps you mean the total modulating signal of V plus the 2.5kHz component in which case

Vmod_total_rms={V^2+[Vrms_2.5kHz_component]^2}^(1/2)

If you mean the RMS of the total modulated signal (including carrier) I'll leave that to you ....