a) Figure Q1(a) shows a sinusoidal modulated DSBFC (or DSBLC) waveform with modulating signal period, Tm of 1 msec and carrier signal period, TC of 0.125 msec, respectively. Figure Q1 (a): Full AM Waveform i. Determine the modulation index, m ii. Determine the modulating frequency, fm and the carrier frequency, fc iii. Sketch a line spectrum iv. Calculate the ratio of the average power in the sidebands to that of the carrier v. Determine the amplitude of the additional carrier which must be added to attain a modulation index of 10%
![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).](https://www.doubtrix.com/uploads/editor/7357981963vsAWMIuOad.png)
![Question 4. [20 points] Consider the Double Sideband-Large Carrier (DSB-LC) modulated signal s(t) : s(t) = 10cos(304×103πt) + Acos(300×103πt) + 10cos(296×103πt) a) Determine the message signal m(t) and the carrier signal c(t). b) Calculate the carrier power and the power in the sidebands. c) Find A for the modulation index, μ = 0.8. d) Find A for a power efficiency of 10%.](https://www.doubtrix.com/uploads/editor/7328850374DpNrrxINsY.jpeg)
