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An amplitude modulated (AM) signal, xAM(t), is represented by the following expression: xAM(t) = [Ac + m(t)]cos⁡(2πfct + π). The carrier frequency, fc = 107 Hz and the power in the modulation signal, m(t), is represented as Pm. (i) Derive an expression for the power efficiency, η, of the AM signal, xAM(t), in terms of Pm. (ii) Given that the modulation index, μ = 0.5, determine the power efficiency, η, of the modulating signal m(t) shown in Figure B1 c overleaf. Figure B1 c: Triangular waveform as modulating signal, m(t).

An amplitude modulated (AM) signal, xAM(t), is represented by the following expression: xAM(t) = [Ac + m(t)]cos⁡(2πfct + π). The carrier frequency, fc = 107 Hz and the power in the modulation signal, m(t), is represented as Pm. (i) Derive an expression for the power efficiency, η, of the AM signal, xAM(t), in terms of Pm. (ii) Given that the modulation index, μ = 0.5, determine the power efficiency, η, of the modulating signal m(t) shown in Figure B1 c overleaf. Figure B1 c: Triangular waveform as modulating signal, m(t).

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An amplitude modulated (AM) signal, x A M ( t ) , is represented by the following expression:
x A M ( t ) = [ A c + m ( t ) ] cos ⁡ ( 2 π f c t + π ) .
The carrier frequency, f c = 10 7 H z and the power in the modulation signal, m ( t ) , is represented as P m . (i) Derive an expression for the power efficiency, η , of the AM signal, x A M ( t ) , in terms of P m . (ii) Given that the modulation index, μ = 0.5 , determine the power efficiency, η , of the modulating signal m ( t ) shown in Figure B1c overleaf.
Figure B1c: Triangular waveform as modulating signal, m ( t ) .

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