The output of an AM modulator is given by x(t)=A_{c} \cos (2000 \pi t)+50 \cos (2100 \pi t)+50 \cos (1900 \pi t) The carrier power is 5 kW. a. Determine the modulation index ma. b. Write an expression for the normalized modulating signal. c. Calculate the power efficiency. d. Calculate the PEP supplied by the AM transmitter and compareit with the normalized average power and the carrier power.