Question

A FM Broad cast transmitter, using modulating signal of frequency 20 kHz has a deviation ratio of 10. The Bandwidth required for transmission is

• A. 220 kHz
• B. 180 kHz
• C. 360 kHz
• D. 440 kHz

Answer 1

Answer: (D)

440 kHz

Answer 2

The modulating frequency is $f=20 kHz$

The deviation ratio is $\frac{frequency \space deviation}{modulating \space frequency}=\frac{∆f}{f}$

Frequency deviation $∆f=f×10=20 kHz×10=200$

The bandwidth is given by $2f+∆f=220+200=440 kHz$