Pokhara University
Bachelor of Engineering in Computer Engineering
Semester 3 · PU Spring 2023
Course Title: Data Communication
Full Marks: 100Pass Marks: 45Time: 3hrs.
Candidates are required to give their answers in their own words as far as practicable.
- 1.15
- a) What are standards? Explain its types. Also explain the standard organizations in data communication.
- b) Define bit rate and baud rate? Explain with a scenario to show bit rate is not always equal to baud rate with suitable diagram and calculations.
- 2.8
- a) Define Time Invariant System. Explain the following properties of the systems: a) causality b)linearity c)stability d)memory
- b) Explain deterministic and random signal with example. Justify 443 whether unit step signal is energy signal or power signal
- 3.15
- a) Explain the existence of Fourier Transform. Find the Fourier Transform of Signum function.
- b) Compare and Contrast Frame relay, X.25 and ATM.
- 4.15
- a) Why optical fiber is considered advantageous over other copper media? Explain. Also, explain about different propagation techniques.
- b) A bit stream is 10011101 is transmitted using the standard CRC method. The generator polynomial is x*+1. Derive the actual bit string transmitted. Show that the error is detected if any one bit in the received bit stream is inverted.
- 5.15
- a) Define flow control as a layered protocol model. Explain the mechanism of a flow control for an ARQ model.
- b) Compare and Contrast between Virtual Circuit Network and Datagram = network.
- 6.15
- a) Differentiate between encoding and modulation? Explain differential PSK with an example.
- b) How modulation helps to reduce the size of antenna, illustrate in brief. Explain about, amplitude, frequency and phase modulation. rs err)
- 7.
Write short notes on: (Any two) 2x5
- a) Synchronous and asynchronous Communication
- b) Types of Switching mK i ee 2
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