AP EAMCET · PHYSICS · Communication System
If a message signal of frequency \(10 \mathrm{kHz}\) and peak voltage \(12 \mathrm{~V}\) is used to modulate a carrier wave of frequency \(1 \mathrm{MHz}\), the modulation index is 0.6 . To make the modulation index 0.75 , the carrier peak voltage should be
- A decreased by \(25 \%\)
- B increased by \(25 \%\)
- C decreased by \(20 \%\)
- D increased by \(20 \%\)
Answer & Solution
Correct Answer
(C) decreased by \(20 \%\)
Step-by-step Solution
Detailed explanation
Modulation index, \(M=\frac{V_{\text {peak, signal }}}{V_{\text {peak, carrier }}}\) Let's write \(V_{\text {peak, carrier }}=V\) In first case, \(0.6=\frac{12}{V}\) \(\Rightarrow \quad V=20 \mathrm{~V}\) In second case, \(0.75=\frac{12}{V^{\prime}}\)…
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