Question

An amplitude modulation (AM) scheme uses tone modulation, with modulation index of 0.6. The power efficiency of the AM scheme is \(\underline{\hspace{2cm}}\) % (rounded off to one decimal place).

Hint:

The power efficiency in an AM scheme depends on the modulation index and can be calculated using the formula \( \eta = \frac{m^2}{1 + m^2} \).

Answer 1

Correct Answer: 15

The power efficiency \( \eta \) of an AM scheme is given by the formula: \[ \eta = \frac{m^2}{1 + m^2} \] where \( m \) is the modulation index. Given \( m = 0.6 \), we substitute into the formula: \[ \eta = \frac{(0.6)^2}{1 + (0.6)^2} = \frac{0.36}{1.36} \approx 0.2647 \] Multiplying by 100 to convert to percentage: \[ \eta \approx 26.5% \] Thus, the power efficiency of the AM scheme is \( 26.5 % \).