Question

The total output power of an AM transmitter that is being operated at 50% modulation is measured to be 1800 watts. What is the carrier power?

a. 1440 watts
b. 1600 watts
c. 900 watts
d. 2025 watts

Answer 1

b. 1600 watts

Step-by-step explanation:

Modulation is the process of impressing a low frequency signal unto a high frequency signal so a to transmit over long distance.

If the modulation index (m) for an AM wave is less than 1, modulation would occur with no distortion, if m = 1, modulation occurs but if m > 1, it leads to over modulation and loss in AM envelope.

The total output power of an AM is the sum of the carrier power, upper side band power and lower side band power.

Total output power of an AM
`(P_(AM))=((2+m^2)/(2) )P_c\\`

Pc is the carrier power. Given that modulation (m) = 50% = 0.5:

`P_(AM)=(2+m^2)/(2) P_c\\\\1800=(2+0.5^2)/(2) P_c\\\\1800=1.125P_c\\\\P_c=1600\ watts`