GATE 2023 Communication System Quiz 32

A sinusoidal message signal, m(t) = Am cos (2pf_mt) is applied to a frequency modulator and a phase modulator separately. If β_FM is the modulation index of the FM signal and β_PM is the modulation index of the PM signal, then select the correct one of the following statements?

An FM signal  is modulated by waveform shown in fig.

Find the value of K_f(Hz/V) so that peak-to-peak frequency deviation is 50 KHz.

Consider an angle modulated signal x(t) = 2 cos[2π × 10⁵t + 2cos2π × 10² t]. Let the instantaneous frequency at t = 5 m sec will be f₁ and maximum frequency deviation is f₂ then f₁ + f₂ is ______ × 10² Hz.

A sinusoidal carrier wave of frequency of f_c =100M Hz is exponentially modulated by a modulating signal x(t). find maximum and minimum instantaneous frequency.    

 if resulting signal is PM with sensitivity k_P= 10π Hz/v