# In an Amplitude Modulate (AM) wave with 100% modulation (m), the carrier is suppressed. The percentage of power saving will be:

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In an Amplitude Modulate (AM) wave with 100% modulation (m), the carrier is suppressed. The percentage of power saving will be:
1. 100%
2. 50%
3. 25%
4. 66.7%

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Correct Answer - Option 4 : 66.7%

Concept:

The total transmitted power for an AM system is given by:

${P_t} = {P_c}\left( {1 + \frac{{{μ^2}}}{2}} \right)$

Pc = Carrier Power

μ = Modulation Index

Calculation:

When the carrier power is suppressed, power saving in the AM wave is carrier power which is not transmitted.

% power saving = (power saved/total power of AM) × 100

$= \frac{{{P_c}}}{{{P_c}\left( {1 + \frac{{{\mu ^2}}}{2}} \right)}} \times 100$

$= \frac{2}{{2 + {\mu ^2}}} \times 100$

For μ = 1,

$= \frac{2}{{2 + 1}} \times 100 = 66.67\%$