Frequency Modulation Theory and Spectrum Analysis Quiz

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What is the carrier frequency for a 110 FM signal that is modulated by a 5 KHz sine wave and has a frequency deviation of 25 KHz?

110.1 MHz (correct)

110.125 MHz

110.05 MHz

110.025 MHz

In Frequency Modulation (FM), why does the number of sidebands (BW of FM) depend on the modulation index?

To reduce interference

To improve signal clarity

To control the spectrum occupancy (correct)

To increase the carrier swing

For an FM signal with a modulation index of 5, what will be the carrier swing if the frequency deviation is 30 KHz?

90 KHz (correct)

150 KHz

120 KHz

60 KHz

What is the modulation index for an FM signal with a carrier swing of 80 KHz and a modulating frequency of 15 KHz?

3.33 Signup and view all the answers

In Frequency Modulation, what is the primary reason for developing this modulation technique over amplitude modulation (AM)?

To minimize noise interference Signup and view all the answers

If an FM signal has a modulation index of 4 and a modulation frequency of 10 KHz, what would be the frequency deviation for this signal to have a carrier swing of 60 KHz?

30 KHz Signup and view all the answers

Which of the following is NOT a reason for developing frequency modulation (FM)?

To increase the power efficiency of the transmitted signal Signup and view all the answers

In frequency modulation, what is the relationship between the modulation index ($m_f$) and the frequency deviation ($\Delta f$)?

$m_f = \Delta f / f_c$ Signup and view all the answers

If the maximum frequency deviation in an FM system is 75 kHz, and the modulating signal frequency is 10 kHz, what is the maximum possible modulation index?

7.5 Signup and view all the answers

In an FM system, what is the relationship between the transmitted power and the modulation index?

The transmitted power is independent of the modulation index Signup and view all the answers

Which of the following statements about FM is correct?

FM signals require a wider bandwidth than AM signals for the same modulating signal Signup and view all the answers

In an FM system, if the carrier frequency is 100 MHz and the maximum frequency deviation is 75 kHz, what is the maximum bandwidth required for the FM signal?

150 kHz Signup and view all the answers

What is the primary reason for developing Frequency Modulation (FM)?

To reduce the effect of noise on the amplitude-modulated signal Signup and view all the answers

In Frequency Modulation (FM), what is the relationship between the modulated frequency ($f_{FM}$) and the carrier frequency ($f_c$), frequency deviation ($\Delta f$), and modulating signal frequency ($f_m$)?

$f_{FM} = f_c + \Delta f \sin(2\pi f_m t)$ Signup and view all the answers

What is the frequency deviation ($\Delta f$) in Frequency Modulation (FM)?

The maximum change in frequency of the modulated wave Signup and view all the answers

What is the carrier swing in Frequency Modulation (FM)?

The total variation in frequency from the lowest to the highest value Signup and view all the answers

In Frequency Modulation (FM), what is the modulation index ($\beta$) defined as?

$\beta = \frac{\Delta f}{f_c}$ Signup and view all the answers

In Frequency Modulation (FM), what is the expression for the power of the modulated signal ($P_{FM}$) in terms of the carrier amplitude ($A$) and the modulation index ($\beta$)?

$P_{FM} = \frac{A^2}{2} \left(1 + \frac{\beta^2}{2}\right)$ Signup and view all the answers