Electrical Communications Systems

Course No. 0909-331-01

Spring 2005


 
 
 

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Laboratory Project 2

AM and DSB-SC Modulation and Detection

Suggestions for a Good Laboratory Report

  • The following suggestions, specific to the various sections of your lab report are meant to be a listing of minimum expectations.
  • There is a lot to discover about ECOMMS as you do the labs - so keep your eyes and ears open - and record everything! (Also have fun...).
  • Feel free to experiment - i.e. do more than the suggested lab activity. This will improve your lab score.
  • You are encouraged to observe and record more than the minimum suggested here - this will also improve your lab score.
  • Talk to the instructor often - especially when you see/hear something that you cannot explain.

Page 1. Cover page 

  • Project Number
  • Project Title.
  • Course Number.
  • Names of Group Members.
  • Date handed in.

Pages 2 - 5

  • Objective
  • Equipment and Software used.
    • List exactly what you used.
  • Approach (Theory)
    • Part 1: Derive the design the equation for the envelope detector. Why does the envelope detector exhibit ripple and harmonic distortion? How do the effects of ripple and harmonic distortion appear in the time and frequency domains? What effects do these have on AF sound quality? What do we expect to see in the time and frequency domains when we vary the SNR? What effects does this  have on AF sound quality?
    • Part 2: How does the LM1496 behave as a double-balanced modulator to generate DSB-SC? What are the effects of loss of synchronization with the local oscillator with the incoming carrier (the quadrature-null effect)? What do we expect to see in the time and frequency domains?
  • Procedure
    • List what you actually did.

Page 6 - 

  • Results (tables and graphs)
    • Matlab figures of the time and spectral domain representations of the various waveforms  - label all axes.
  • Discussion of Results and Conclusions. 
    • Did you see what you expected in the time and spectral domains? If not, why not?
    • List the virtues and limitations of AM and DSB-SC as you have observed in your laboratory experiments.

Appendix 

  • Program listings, etc..
    • All your Matlab m-files.