- Fm Modulator Deviation Sensitivity Kr 1 5khz V Carrier Frequency F 1mhz Modulating Signal Vm T 4 Sin 27x10 T 1 (35.17 KiB) Viewed 57 times
FM Modulator Deviation sensitivity, kr= 1.5kHz/V Carrier frequency, f. = 1MHz Modulating signal, Vm(t) = 4 sin (27x10³t) (i) Define what is meant by frequency deviation, Aco (Af). (3 marks) (ii) Describe the purpose of a limiter in an FM receiver. (2 marks) (iii) Determine the modulation index, ß and sketch the spectrum for the modulator. (5 marks) (iv) Describe the changes to the modulated signal if the amplitude OR frequency the modulating signal is varied. of (5 marks) (v) Calculate the BW of the modulator using Carson's rule. (2 marks) (vi) Calculate the normalized power within HALF the bandwidth calculated in (v). (3 marks) Bessel Table B/J.(B) Jo J₁ J₂ J4 Js J6 0.5 0.94 0.24 0.03 1 0.76 0.44 0.11 0.02 2 0.22 0.58 0.35 0.13 0.03 3 -0.26 0.34 0.49 0.31 0.13 0.04 0.01