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t+β t+β t) .What is the maximum

The document contains questions about various topics in digital communication systems including: 1) Line coding, disadvantages of PCM, types of pulse digital schemes, intersymbol interference, and companding. 2) Calculating power, bandwidth, and filter bandwidth for an FM modulated signal with a given carrier frequency, message amplitude and frequency, and frequency deviation constant. 3) Determining the maximum deviation of the instantaneous frequency from the carrier frequency for an FM wave with two modulating signals. 4) Calculating the ratio of phase and frequency constants to achieve the same maximum phase deviation for a signal applied to both a phase and frequency modulator. 5) Explaining a PLL FM demodulator, spectral

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Sukanti Pal
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116 views1 page

t+β t+β t) .What is the maximum

The document contains questions about various topics in digital communication systems including: 1) Line coding, disadvantages of PCM, types of pulse digital schemes, intersymbol interference, and companding. 2) Calculating power, bandwidth, and filter bandwidth for an FM modulated signal with a given carrier frequency, message amplitude and frequency, and frequency deviation constant. 3) Determining the maximum deviation of the instantaneous frequency from the carrier frequency for an FM wave with two modulating signals. 4) Calculating the ratio of phase and frequency constants to achieve the same maximum phase deviation for a signal applied to both a phase and frequency modulator. 5) Explaining a PLL FM demodulator, spectral

Uploaded by

Sukanti Pal
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
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1.

a. What is line coding?


b. What are the disadvantages of PCM?
c. How many types of Pulse digital scheme are there?
d. What is the effect of inter symbol interference?
e. What is companding?
f. what are the advantages of VSB?

2. A FM modulator is used to transmit a tone message with amplitude of 4 volts and frequency of
20 Hz. The frequency deviation constant for the modulator is 25Hz/V, and the carrier wave
has amplitude 10 Volts and frequency 2000 Hz.

a. What is the power of FM modulated Signal?


b. What is the approximate band width of the FM modulated signal using Carson’s rule?
c. The output of the FM modulator is passed through a bandpass filter centered at 2000 Hz.
What should be the bandwidth of the filter such that 90% of the power in the modulated
signal passes through.
d. How would your answer to part b) change if the amplitude of the message is doubled?
e. How would your answer to part b) change if the frequency of the carrier is doubled?

3. Consider an FM wave f (t)=cos[2 π f c t + β 1 sin 2 π f 1 t + β 2 2 π f 2 t ] .What is the maximum


deviation of the instantaneous frequency from the carrier frequency f c.

4. The signal m(t) as shown I applied both to a phase modulator (with k p as the phase constant)
and a frequency modulator with (k f as the frequency constant) having the same carrier
kp
frequency .What is the ratio (in rad /Hz) for the same maximum phase deviation.
kf

5. Explain the PLL- FM demodulator.


6. Describe the spectral representation of PWM and PPM.
7. Explain PCM generator with neat diagram.
8. Explain Delta modulation.

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