In case of wideband FM, the modulation index value is :
exceeds unity
To understand the modulation index in the context of wideband FM, let's first define what modulation index is in frequency modulation (FM). The modulation index of FM is given by the formula:
\(\beta = \frac{\Delta f}{f_m}\)
where:
- \(\Delta f\) is the peak frequency deviation, which is the maximum shift from the carrier frequency.
- \(f_m\) is the maximum modulating signal frequency.
In wideband FM, the modulation index (\(\beta\)) is significantly greater than one, often much larger. This is because wideband FM transmits a greater range of frequencies, requiring a larger frequency deviation to accurately capture the modulation characteristics.
Let us analyze each option to identify the correct one:
- Around zero: This would imply negligible modulation, which is not the characteristic of wideband FM.
- Much less than unity: This characterizes narrowband FM, where modulation index is typically less than or approximately equal to 0.3.
- Unity: This implies the modulation index equals one, which is not representative of wideband FM but might be applicable in certain narrowband cases.
- Exceeds unity: Correct choice, as wideband FM has a modulation index greater than one, often significantly larger.
Therefore, the modulation index value in the case of wideband FM is exceeds unity.
Similar Questions
In FM
Consider the following :
ST1 : F.M. signal produces more side bands than A.M.
ST2 : The carrier in a F.M. signal can never be dropped to zero amplitude.Which of the following is valid ?
Which of the following is true ?
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(A) Crystal Oscillator
(B) Antenna
(C) Frequency multiplier
(D) Phase modulate / Audio source
(E) Power amplifierChoose the most appropriate answer from the options given below :
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\(s(t) = 10\sin\left(4\pi \times 10^6 t + 9\cos\left(2\pi \times 10^3 t\right)\right)\)
the frequency deviation and bandwidth of FM wave are
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The approximate rule for transmission of an FM signal generated by a single-tone modulating signal of frequency fm, modulation index β and maximum frequency deviation Δf, is defined as :
Assertion (A) : The FM radio broadcast of analog signals provides higher fidelity.
Reason (R) : FM uses significantly larger channel bandwidth for signal transmission.
Select your answer using the codes given below :
What bandwidth is needed for an FM signal that has a peak deviation of ± 3 KHz and handles audio signals from 200 Hz to 5 KHz ?
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1. Armstrong
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3. Balanced Modulator
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Important Questions from Frequency Modulation
Which of the following statements is true for FM?
What is the modulation index in a frequency modulated signal with a modulating frequency of 500 Hz and frequency deviation of 10 kHz?
Which of the following rules states that the bandwidth required to transmit an angle modulated wave is twice the sum of the peak frequency deviation and highest modulating signal frequency?
If f mis modulating frequency and m fis modulation index, then by the Carson's rule, the bandwidth of an FM signal at the input of a conventional discriminator will be:
In FM, "M" stands for
