QUESTION 1
a. The antenna current of an AM transmitter is 8A. If only the carrier is sent, but it increases to 8.93A if the carrier is modulated by a single sinusoidal wave, determine the percentage modulation. Also, find the antenna current if the percent of modulation changes to 80%.
QUESTION 2
a. Numerical - Power in Amplitude Modulation - 100% Modulation
An unmodulated AM signal produces a current of 5.4 A. If the modulation is 100 percent, calculate (i) the carrier power, (ii) the total power, and (iii) the sideband power when it is transmitted through an antenna having an impedance of 50.
b. To analyze noise in communication systems, by the application of resistance in parallel, show that
VRMS = V / √(4KCTB R+R)
b. i. Simplex, Half duplex, and Full duplex in transmission network can be described as what?
ii. Distinguish between analog signal and digital signal. Support your answer with simple waveform diagrams.
c. Under multiplexing and demultiplexing in transmission systems, give the full meaning of FDM, WDM, CDMA, and SDMA.