Home/
Competitive Exams/
JEE Main & Advanced/
Physics/
Principles of Communication/
Question 20293
JEE Physics · Hard

Principles of Communication: Frequency Modulation MCQ

Solve this quality-checked JEE multiple-choice question, then review the correct answer and explanation.

Timer-based practiceDetailed answer reviewMobile-friendly flow
Frequency ModulationHardQuestion 20293

Question

By Bessel function analysis, an FM signal with β = 2.4 theoretically has how many significant sidebands on each side?
  1. A
    1
  2. B
    2
  3. C
    4
    Correct
  4. D
    6

Correct answer

4

Explanation

For FM modulation index β, the number of significant sideband pairs is approximately β + 1 to β + 2 from Bessel function analysis. For β = 2.4, significant sidebands extend to n = 4 (J₁ through J₄ are significant). Bandwidth = 2 × 4 × fm (exact) vs. Carson's rule 2(Δf + fm) = 2(2.4+1)fm = 6.8fm ≈ 2×4fm.

Review Principles of Communication notesStart timed chapter practice