Question 1
A 10-MHz carrier is frequency modulated by a 10-KHz sinusoid so that the peak frequency deviation is
100 Hz. Determine
a) The approximate bandwidth of the FM signal.
b) The bandwidth if the modulation signal amplitude is doubled
c) The bandwidth if the modulation signal frequency is doubled
d) The bandwidth if both the modulation signal amplitude and frequency are doubled
e)
Question 2
A frequency modulated signal is given by
() = 10 (2 ⨯ 105
+ 5 sin(2 ⨯ 1500) + 2sin(2 ⨯ 1000))
What is the frequency modulation index of the above signal?
Question 3
The sinusoidal signal () = cos(2000) is applied to the input of an FM system. The corresponding
modulated signal output is
() = 100(2 ⨯ 107
+ 4 sin(2000))
Across a 50-ohm resistive load.
a) What is the peak frequency deviation from the carrier?
b) What is the total average power developed by ()?
c) What is the percentage of the average power at 10 MHz?
d) What is the approximation bandwidth using Carson’s rule?