# Frequency deviation calculation from FM equation

## Calculate the maximum frequency deviation for the FM signal

v(t)= 10 cos(6000t+ 5sin2200t)

a) 2200 Hz

b) 6000Hz

c) 1750Hz

d) 11000Hz

Correct Answer: c) 1750Hz

**Explanation:**

A standard FM signal is represented by

v(t)= A_{c} cos(2πf_{c}t+ k_{f}sin2πf_{m}t)

A_{c} = carrier amplitude

f_{c}= carrier frequency

k_{f}= modulation index

f_{m }= modulating frequency = 2200/2π = 350 Hz

k_{f} = frequency deviation/modulating frequency

5= freq deviation/ 350

Therefore, deviation= 5 *350

= 1750Hz