Question

An AM transmitter radiates 10kW power at 85% modulation. What would be power saving if the carrier and one of sidebands are suppressed?

Answer 1

P_T = 10W, m_a = 85%

= \(\frac{85}{100}\)

P_T = P_c(1 + \(\frac{m_a^2}{2}\))

10 = P_c[1 + \(\frac{(0.85)^2}{2}\)]

10 = P_c[1.361]

P_c = \(\frac{10}{1.361}\)

P_c = 7.347 kW

P_T = P_c + P_LSB + P_USB

10 = 6.131 + P₁ + P₁ {Where P₁ is Power in each sideband}

10 - 7.347 = 2P₁

2P₁ = 2.653

P₁ = 1.326kW

Percentage saving in power