DORDT COLLEGE ENGINEERING DEPARTMENT
INTRODUCTION TO COMMUNICATION SYSTEMS—EGR 363
(Spring 2010)

PROBLEM SETS

(Last update: 5/05/2010 5:30 pm)
PS
#  
Assigned Due Returned Problems Assigned
(In Proakis & Salehi unless otherwise noted)
11

4/21 4/30 5/04   Read 5.1
  Do 5.3, 5.5, 5.9, 5.10, 5.11 parts 1 and 2 only.
 
  Hints on 5.11
  Part 3) You can't use Eq. 5.1.11 (Why?)
              Use techniques discussed in class.
  Part 4) The integral you encounter is not too
              hard. What is d/dy(exp(y2/2s2))?
  Part 5) You can use Eq. 5.1.11.

 
  As discussed in class on Wed. 4/28, parts 3,
  4 and 5 of problem 5.11 have been deleted from
  this problem set. We have run out of time.
10

4/12 4/16 4/21   Review 4.2
  Do 4.4, 4.5
9

3/29 4/7 4/21   Read 4.1, 4.2
  Do this problem (not in the text): 3-A
  Do 4.1
 
  Hints on problem 4.1
  --For part one you should leave the integral
  unsolved. The "sine integral" is a tabulated
  function with no known analytic solution. Just
  show the integral in your solution.
  Some details of the Sine Integral can be found here
  A well known but heavy authority on topics like this is
  the handbook by Abramowitz and Stegun. Available in
  the John and Louise Hulst Library (you will see that this
  handbook is literally heavy) or electronically. See
  especially Section 5.2 if you like these details.

  You should also pay attention to units. The
  modulation index, is always dimensionless. The
  The deviation constant, kf is usually in Hz/V in
  our text.
  --For part three, delete the word "content" from
  the question. Since the frequency and phase
  of the R.F. signal vary only slowly relative to
  the carrier you can assume m(t) = 0 to find the
  power and you will get the same result as if
  m(t) were not zero.
  --For part four use Carson's Rule.
 
  (The solution to 3-A is not posted.)
8

3/03 3/26 3/29   Read 3.3, 3.4, 3.5
  Do 3.16, 3.18, 3.24
 
  (The solution to 3.18 is not posted)
7

2/22 2/26 3/03   Review previous reading assignment
  Do 3.14.
6

2/12 2/19 2/22   Read the "Modulation Theorem" on page 72-74.
  Review problem 2.51 which shows that
  multiplication in the time domain is equivalent
  to convolution in the frequency domain. This
  is a useful theorem.
  Read 3.1, 3.2
  Do 3.1, 3.3, 3.5
  Note errata on problems 3.1, 3.3, 3.5.
5

2/05 2/12 2/17   Read Section 2.3, Review 2.1, 2.2
  Do 2.26, 2.46.1, 2.46.2, 2.51
 
  Hint: A direct application of the Fourier
  Transform's analysis equation to problems
  2.46.1 and 2.46.2 results in a challenging
  integral. A lookup table of integrals would
  be a potential way to get a correct answer,
  but these integrals are usually not given in
  the types of lookup tables included in a
  typical calculus textbook. Instead, one can
  use the table on page 81 of our text as a
  lookup table of integrals. Application of the
  properties of Fourier Transforms is also
  helpful.
4

1/29 2/05 2/10












L. Euler
  Review Sections 2.1, 2.2
  Do 2.34.2, 2.34.6, 2.39.5, 2.39.11, 2.39.12
 
  Note publisher's errata on 2.39, page 113,
  lines 6 through 17.
  In general, the subscript on x(t) should match the
  problem part number.
 
  Hint for 2.39.5: x5(t) is a very simple signal given
  in a messy form.
 
  Hint for 2.39.11 and 2.39.12: Use a corollary
  of Euler's formula to expess the signal as a
  complex exponential. Exponentials are easier
  to integrate than trigonometric functions.
  (See the end of this page on Euler's formula.)
3

1/25 1/29 2/03   Review Section 2.1. Read 2.2.
  Do 2.5, 2.6, 2.7, 2.24, 2.34.3
 
  Note errata on Problem 2.6.
2

1/20 1/22 2/03   Review Chapter 2, Section 2.1
  Do 2.2.1, 2.2.2, 2.2.3
1

1/13 1/20
 
1/27   Read Chapter 1, Chapter 2 Section 2.1
  Do (page 105) 2.1.1, 2.1.3, 2.1.5, 2.1.7, 2.1.9
  Use a Matlab script ("m-file") to make the plots.
  Write the problem statement into the script as
  a comment. Import the script and the plot into
  a word processor file to control fomatting and
  to print.
 
  Note errata on page 31 and errata on page 44.

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