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 ?
A high frequency signal is frequency modulated by n number of modulating signals. The ideal number of sidebands in the modulated signal will be :
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 ?
Which of the following techniques are used to generate frequency modulated signal :
1. Armstrong
2. Foster-Sealy Discriminator
3. Balanced Modulator
4. Reactance ModulatorWhich one of the following is true ?
A carrier is frequency modulated with a sinusoidal signal of ____ KHz resulting in a maximum frequency deviation of 5 KHz. Modulation index and bandwidth of the modulating signal is respectively is given as
A fm kc/s modulating frequency provides Mf = 2 (significant Bessel functions i.e. n = 4) in F.M. wave. What bandwidth is required for passing this wave keeping ∆f constant, if frequency of modulating signal is doubled what will be its effect on Mf ?
Which of the following is true ?
Important Questions from Frequency Modulation
Given an angle-modulated signal
$x_c(t) = 10\cos[(10^8) \pi t+5\sin 2\pi (10^3)t]$
The maximum phase deviation and maximum frequency deviation is given byIn 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 ?
A high frequency signal is frequency modulated by n number of modulating signals. The ideal number of sidebands in the modulated signal will be :
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 :
