# Solving for frequency deviation, $\Delta f$ (FM modulation)

I'm sorry if I posted this in the wrong section. I solved the question and got $50\textrm{kHz}$, but the solution says it is $100\textrm{kHz}$ without any proof.

Im asking for someone to tell me which is correct.

• Welcome to DSP.SE! Which particular question are you trying to answer. There are many on that page. – Peter K. Jun 8 '16 at 15:09
• I am trying to answer exercise 3, part 1. (The one with the line figure and VCO) – user6019827 Jun 8 '16 at 15:10

then for the given example you indeed have $\Delta f=50\;\text{kHz}$, because the nominal carrier frequency is $f_c=10\;\text{MHz}$, the maximum frequency is $f_c+\Delta f=10.05\;\text{MHz}$, and the minimum frequency is $f_c-\Delta f=9.95\;\text{MHz}$.