Problem 3: The output signal of an AM modulator is given by 4(+) = 5(cos (1800 πt) + cos(2200μt)] +20 cos (20007+)] ☹ Determine the modulating signal m(t). and the carrier c(t) ⑤ Determine the modulation indese, a Determine the ratio of the power in the sidebands to the power in the carrier. Hint: start by using a trigonometric identity.

Assume the modulated signal s(t) = 4cos(10πt)cos(1000πt). What type of modulation does this correspond to? a.DSB-SC b.SSB-SC c.FM d.AM

2-Most of the power in an AM signal is in the a. Carrier b. Upper sideband c. Lower sideband d. Modulating signal

An FM signal has a maximum frequency deviation of 1500h and a modulating frequency of 500h, its total power is 6500w, applied to a resistive load of 1ohm, the carrier frequency is 400Mhz. Determine the voltage of the modulated signal and the modulation voltage.

IX. A carrier signal is amplitude modulated by a sinewave. The resulting AM waveform is shown below. a) b) c) d) 5.5V- 2V What is the percentage of modulation? What is the amplitude of the carrier signal? To achieve 75 percent modulation, what amplitude of the modulating signal is needed? Calculate the effective voltage of the AM signal

A sinusoidally modulated AM waveform is shown below: Determine: a) Peak amplitude of the upper and lower side frequencies. b) Peak amplitude of the unmodulated carrier. The modulation index. The carrier power and the power in the sidebands. The total transmitted power. 3 0 -3 -9 The transmission efficiency. The amplitude of the carrier which must be added or subtracted to attain a modulation index of 0.5. In AM modulation, the modulation index is kept < 100%, why?

D E F

We have a baseband channel with a 1-MHz bandwidth. What is the data ratefor this channel if we use each of the following line coding schemes? a. NRZ-L b. Manchester c. MLT-3 d. 2B1Q

Q2: A modulating signal is used to modulate a carrier signal(AM modulation). Let Pr . Pc. PSB. PuSB. PLSB and u are the total power, carrier power, side band power, upper side band power, lower side band power and modulation index respectively. Prove the following: a. Pc = Pr () c. Pusn = Pisn =) Pr m2 b. Psn = Pr %3D 2+m2 LSB 2+m? (2+m2

3.7 A modulating signal is of the form: m(t) = 5 sin (2000nt) and the carrier signal c(t) = 10 sin (20000rt) 1. Determine the modulation index. 2. Find the percentage of modulation. 3. Find the frequencies of the sideband. 4. Find the amplitude of each the side bands. 5. What will be the bandwidth of the modulated signal?