Discussion Forum



1)

A signal of 5 kHz frequency is amplitude modulated on a carrier wave of frequency 2MHz. The frequencies of the resultant signal is/are


A) 2MHz only

B) 2005 kHz and 1995 kHz

C) 2005 kHz 2000 kHz and 1995 kHz

D) 2000 kHz and 1995 kHz

Answer:

Option C

Explanation:

Central Idea Frequency associated with AM are   $f_{c}-f_{m},f,f_{c}+f_{m}$

  According to the question

                 $f_{c}=2MHz=2000kHz$

                  $f_{m}=5kHz$

 Thus, frequency of the resultant  signal  is/are carrier frequency   $f_{c}$  = 2000kHz,

 LSB frequency   $f_{c}-f_{m}$=2000kHz-5kHz=1995 kHz     and USB Freequency  $f_{c}+f_{m}$=2005kHz