Question

The amplitude of a sinusoidal carrier signal with a peak value of 10 V is modulated by another sinusoidal signal. If the modulation index of the resultant AM signal is 0.4. then the maximum and minimum values of the envelope of the AM signal are respectively equal to

• A. 6 V and 4 V
• B. 10.4 V and 9.6 V
• C. 10.8 V and 9.2 V
• D. 14 V and 6 V

Answer 1

The correct option is D 14 V and 6 V

The maximum and minimum value of the envelope of an AM modulated signal can be given as,

$E_{max}=A_c(1+\mu )$

$E_{max}=A_c(1-\mu )$

Given that, $A_c=10Vand\mu =0.4$

So, $E_{max}=10(1+0.4)V=14V$

$E_{max}=10(1-0.4)V=6V$