The antenna current of an AM transmitter is 8 A when only the carrier is sent, but it increases to 8 . 93 A when the carrier is modulated by a single sine wave. Find the percentage modulation.

Step-by-step solution

The power dissipated in any circuit is a function of the square of voltage across the circuit and the effective resistance of the circuit. Equation of AM wave reveals that it has three components of amplitude Clearly; power output must be distributed among these components. Carrier power, P c = E c / 2 2 R = E c 2 2 R Total power of side bands, P S = m E c / 2 2 2 R + m E c / 2 2 2 R = m 2 E c 2 4 R ∴ P S P C = 1 2 m 2 and P T = P C + P S = P C 1 + m 2 2 ∴ P T P C = 1 + m 2 2 ⇒ I T I C 2 = 1 + m 2 2 Given that, I T