. AM modulation is inefficient. With reference to the frequency domain, explain why. How does double sideband and single sideband suppressed carrier modulation improve the efficiency of AM modulation? Despite its increased efficiency, what is a disadvantage of SSB-SC when compared with AM modulation.
a. AM modulation is inefficient. With reference to the frequency domain, explain why.
How does double sideband and single sideband suppressed carrier modulation improve
the efficiency of AM modulation? Despite its increased efficiency, what is a
disadvantage of SSB-SC when compared with AM modulation.
b. An antenna has an impedance of 75 Ω. An unmodulated AM signal produces a current
of 3.4A. The modulation is 90 percent. Calculate (a) the carrier power, (b) the total
power, and (c) the sideband power.
c. With aid of diagrams, explain how frequency modulation works.
d. A 450-MHz radio transmitter uses FM with a maximum allowed deviation of 6 kHz
and a maximum modulating frequency of 3.5 kHz. What is the minimum bandwidth
required? Use Figure. 5.1 to determine the approximate amplitudes of the carrier and
the first three significant sidebands
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