Digital Communications Slip Test Questions

Slip test-1

  1. In a PCM system, if the Quantization levels are increased from 2 to 8,                 i. Find the change in Signal to Quantization Noise ratio.                                ii.Find the change in Transmission Bandwidth.
  2.  i. Convert the following signal x(t) = 10 cos (200πt) to a discrete signal x[n] if sampling rate is 1000Hz.                                                                                       ii. Write the advantages of Digital Communication system over Analog Communication system.


  1. Draw the Basic Block Diagram of Digital Communication System and explain each block in detail.                                                                                                                             
  2. Deduce the expression for Signal to Quantization noise ratio in PCM system.                                                                  Slip test-2
  1. A PCM source transmits four samples (messages) with a rate 2B samples /second. The probabilities of occurrence of these 4 samples (messages) are equally likely Find out the information rate of the source.                                                           
  2. A source produces 26 symbols with equal probability what is the average information produced by this source?     


  1. State Mutual information. Prove any three properties of Mutual information.                 
  2. A source alphabet has 10 symbols with the given probabilities 0.02, 0.04, 0.17, 0.02, 0.16, 0.06, 0.03, 0.27, 0.20, 0.03 construct Shannon-Fano coding and calculate the efficiency.                                                                                                                             

Author: Lakshmi Prasanna Ponnala

Completed M.Tech in Digital Electronics and Communication Systems.

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