Question
Download Solution PDFAn FM modulator operates at carrier frequency of 250 kHz with frequency deviation sensitivity of 1.5 kHz/V. A PM modulator operates at carrier frequency of 500 kHz with phase deviation sensitivity of 1.5 rad/V. If both FM and PM modulators are modulated by the same modulating signal having peak amplitude of 5 V and modulating frequency of 5 kHz, then what is the relationship between frequency modulation index and phase modulation index?
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFGiven that
FM modulator
fc \( = 200 KHz\)
KF =\( 1.5 KHz\over volt \)
PM modulator
fc\(= 500KHz. \)
KP =\(1.5 rad\over volt\)
Peak amplitude = 5V.
fm = 5KHz
Frequency Modulation index (hf):
Phase modulation index (hp):
\(\beta\)pm = \(KfAm\over fm\) =\( 1.5\times1000\times5\over5000 \) = 1.5
\(\beta\)pm = kp Am = \(1.5\times5\)
\(\beta\)pm =5 \(\beta\)fm
Hence, PM = 5FM.
Here, option 4 is correct.
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