Target Exam

CUET

Subject

Physics

Chapter

Semiconductors and Electronic Devices

Question:

A signal of 5 kHz frequency is amplitude modulated on a carrier wave of frequency 3 MHz. The frequency of the resultant signal are:

Options:

3 MHz and 5 kHz

3005 kHz and 2995 kHz

3000 kHz, 3005 kHz and 2995 kHz

3010 kHz and 2990 kHz

Correct Answer:

3000 kHz, 3005 kHz and 2995 kHz

Explanation:

The correct answer is Option (3) → 3000 kHz, 3005 kHz and 2995 kHz

When a signal of frequency $f_s=5kHz$ is amplitude modulated on a carrier wave of frequency $f_c=3MHz$, the resultant AM signal contains three frequencies -

Carrier frequency $(f_c)=3MHz=3000kHz$

Upper side band frequency = $f_c+f_s=3005kHz$

Lower side band frequency = $f_c-f_s=2995kHz$