Communication
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Questions and Answers

What is the primary reason for maintaining a constant amplitude of the carrier in FM?

  • To reduce the total transmitted power
  • To prevent interference from other signals
  • To maintain the overall amplitude of the FM wave constant (correct)
  • To ensure the side bands are separated from each other by the frequency of the modulating signal

What is the deviation ratio in FM?

  • The ratio of the modulating signal frequency to the carrier frequency
  • The ratio of actual frequency deviation to the maximum allowed frequency deviation
  • The ratio of side bands to the carrier frequency
  • The ratio of maximum permitted frequency deviation to the maximum permitted audio frequency (correct)

What is the expression for the bandwidth of an FM signal?

  • fm × (fc + 2fm)
  • 2n × fm (correct)
  • 2 × fm
  • fc × (fm + 2fm)

What is the percentage of modulation in an FM signal?

<p>The ratio of actual frequency deviation to the maximum allowed frequency deviation (D)</p> Signup and view all the answers

What is the total power of an FM signal?

<p>1.5 × Pc (B)</p> Signup and view all the answers

What is the primary reason for modulation of a low frequency signal?

<p>To enable transmission over long distances without attenuation (B)</p> Signup and view all the answers

Why is the height of the antenna crucial in signal transmission?

<p>To enable efficient radiation and reception (B)</p> Signup and view all the answers

What is the modulation index 'm' given by?

<p>m = m1 + m2 + m3 + ... (D)</p> Signup and view all the answers

What is the range of audible signals?

<p>20 Hz to 20 KHz (A)</p> Signup and view all the answers

What is the wavelength of a 1 MHz frequency?

<p>75 m (B)</p> Signup and view all the answers

What is the bandwidth of an Amplitude Modulation (AM) signal?

<p>(fc + fm) - (fc - fm) (B)</p> Signup and view all the answers

What is the modulation index in Frequency Modulation (FM)?

<p>The ratio of the maximum frequency deviation to the modulating frequency (C)</p> Signup and view all the answers

What is the advantage of Frequency Modulation (FM) over Amplitude Modulation (AM)?

<p>FM is less prone to amplitude-sensitive noise than AM (C)</p> Signup and view all the answers

What is the power dissipated in a circuit in terms of voltage amplitude and resistance?

<p>P = E^2 / R (B)</p> Signup and view all the answers

What is the relationship between the modulation index and the number of sidebands in an AM signal?

<p>The modulation index determines the number of sidebands (C)</p> Signup and view all the answers

What is the process of changing the amplitude of a carrier wave in accordance with the amplitude of the audio frequency signal known as?

<p>Amplitude Modulation (AM) (C)</p> Signup and view all the answers

What remains unchanged in Amplitude Modulation (AM)?

<p>Frequency of the carrier wave (A)</p> Signup and view all the answers

What is the expression for the modulated wave in Amplitude Modulation (AM)?

<p>Ec cos(ωc t) + aEc cos(ωc - ωm)t - aEc cos(ωc + ωm)t (C)</p> Signup and view all the answers

What are the frequencies present in an Amplitude Modulation (AM) wave?

<p>fc, fc + fm, fc - fm (C)</p> Signup and view all the answers

What is the term for the frequencies fc + fm and fc - fm in an Amplitude Modulation (AM) wave?

<p>Side band frequencies (C)</p> Signup and view all the answers

What is the primary reason for the limitation of amplitude modulation?

<p>All of the above (D)</p> Signup and view all the answers

What determines the maximum variation in frequency of the modulated wave for a given modulating signal?

<p>Constant of proportionality (B)</p> Signup and view all the answers

What is the process of changing the frequency of a carrier wave in accordance with the audio frequency signal known as?

<p>Frequency Modulation (D)</p> Signup and view all the answers

What is the ratio of the maximum frequency deviation to the modulating frequency?

<p>Modulation index (D)</p> Signup and view all the answers

What is the total variation in frequency from the lowest to the highest called?

<p>Carrier swing (A)</p> Signup and view all the answers

What is the frequency deviation in Frequency Modulation?

<p>The maximum change in frequency from the mean value (D)</p> Signup and view all the answers

What is the significance of modulation index in Frequency Modulation?

<p>It determines the number of side bands (D)</p> Signup and view all the answers

What is the process of digitising the quantised pulses according to some code?

<p>Coding (A)</p> Signup and view all the answers

What is the type of modulation where the amplitude of the pulse varies in accordance with the modulating signal?

<p>Pulse Amplitude Modulation (PAM) (B)</p> Signup and view all the answers

What is the total power of side bands in an FM signal?

<p>Ec2 / 2R (B)</p> Signup and view all the answers

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