AP EAMCET202022 Sep 2020Evening ShiftPhysicsCommunication SystemActual
A speech signal of 3 kHz is used to modulate a carrier signal of frequency 1 MHz , using amplitude modulation. The frequencies of the side bands will be
Options
- A1.003 MHz and 0.997 MHz
- B3001 kHz and 2997 kHz
- C1003 kHz and 1000 kHz
- D1.0 MHz and 0.997 MHz
Correct answer
A. 1.003 MHz and 0.997 MHz
Step-by-step solution
Frequency of carrier signal, f_c=1 MHz Frequency of message (speech) signal, f_m=3 kHz =0.003 MHz Frequency of upper side band =f_c+f_m =1+0.003=1.003 MHz Frequency of lower side band =f_c-f_m =1-0.003=0.997 MHz