# Carrier frequency in FM equation

## What is the value of carrier frequency in the following equation for the FM signal ?

v(t)= 5 cos(6600t+ 12sin2500t)

**Options:**

a) 1150 Hz

b) 6600 Hz

c) 2500 Hz

d) 1050 Hz

Correct Answer: d) 1050 Hz

**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

k_{f} = frequency deviation/modulating frequency

therefore, f_{c }= 6600/2π

= 1050Hz