Lecturer:          Prof.  E. G. Coffman, Jr.
                         Office hours:  Monday 10:50-11:50am, Tuesday 1:00-2:00pm except on 10/9, 11/13, and 12/11
                                                    when it will be 3:00pm-4:00pm.
                         Office: 813 Schapiro (CEPSR) Bldg.
                         Phone: (212)  854-2152
                         Email: [email protected]
                         URL: http://www.ee.columbia.edu/~egc

TA:        Andreas Constantinides   [email protected]
 

Room:        386 A ET (Engineering Terrace)
 

Time:        MW 9:35-10:50am

Text:        Principles of Communications, Fifth edition, 2002, Ziemer and Tranter
                  Current errata can be found in zterrata.ps

Notes:        Course notes (notes2.ps) will be available prior to class, and are meant to alleviate the burden of
                          note taking, and to be the definitive source of the material you must know for purposes
                          of exams.   Please note that I will be correcting typos as I re-read the notes prior to lectures.
                          If you find what you think are typos, please check the date given on the notes to see if you
                          have the most recent version of the notes.

Calendar information (holidays,  last day to add a class,  last day to exercise pass/fail option,  etc., etc. )

Course structure:
         There will be weekly homework assignments, 2 midterm exams, and a final exam;
                           these will count for  25%, 20%, 20%, and 35%, respectively.
                          The first midterm is scheduled for Wed. Oct. 3, 2001.
                          The second midterm is scheduled for Wed. Nov. 7, 2001

 Problems you may wish to practice on for the midterm next Wednesday include the following.
I give answers, partial answers or hints for each.  Do NOT waste time resolving discrepancies
that arise; we'll take care of that later.

Prob. 3.11   For this problem the modulation index is 12/20 = 0.6, the carrier power is
200W, the sideband power is 36W and the efficiency is 0.1525.

Prob. 3.12  By numerical means you'll find that the minimum value of m(t) is -3.432.
In the positive frequencies there are 7 components.  The efficiency is 19.6%.

Prob. 3.37 According the Carson's rule, the bandwidths are  50.2kHz, 52kHz, 70kHz, and 250kHz

Prob. 3.42 This is a lot of numerical work with Bessel coefficients.  The answers given were
2700Hz and 3000Hz.

Prob. 3.44 Do your elementary circuit analysis and plot the amplitude response to get a
curve that is very nearly linear from 54kHz to 118kHz, so choose a carrier at 86kHz half
way between.  The discriminator constant turns out to be about 8 times 10 to the -6.

Prob. 3.51 Just use Eq. 3.211 and note that where the derivative is 0 we get the steady
state solution.  You'll need to do some inverse sine calculations.  The answer to the
last question is that the loop is not stable for the given value.

Make-up Exam Policy:  Exam dates are announced well in advance.
Information on  scheduling and other course information can be found
on the present web page.

You can always avoid taking a regularly scheduled test, and take
a make-up exam.  However, do be cognizant of the fact that the make-up exam
must be guaranteed to be no easier than the regularly scheduled exam (to be
fair to the majority who adhere to the schedule);  I can only guarantee this by
devising a make-up exam that is definitely harder than the regular exam; I
make every effort to  minimize the added difficulty of the make-up exam.
For grading purposes, the make-up exam grades are combined with the
others, just as if everyone took the same exam.
 
 

Week 1
We begin with Chapter 2 with lectures to be taken from pp. 16 - 36 of the text,
but skipping Section 2.3.

Homework to be turned in Wednesday  9/12/01:
       Probs.  2.2, 2.3(d), 2.4, 2.5(b), 2.6(d,e), 2.7(b,c,e,f), 2.8, 2.9(a,b,c)

The first half of the first lecture introduced physical layer, point-to-point
communication systems: definitions of basic terms, block diagram of a
canonical system, ... .   A history lecture was deferred until later.  In the
second half of the lecture there will be a sharp break into mathematical
foundations, particularly those the student is already familiar with: complex
numbers, signals and their classifications, etc.

The first week was anomalous in that it included 3 lectures up to and including
the lecture on 9/12.  At the end of the first week we had covered the elements
of complex numbers, singularity functions,  signal classifications,  complex Fourier
series, the notion of amplitude and phase spectra, and Fourier transforms and
their properties.

Week 2
We finish up with Fourier transforms,  and then  turn to the basics of linear systems,
particularly filters, in the second week.   Please read pp. 36-72, skipping section 2.6
(which we shall return to later) and section 2.7.13.

Homework to be turned in Wednesday 9/19/01:
       Probs: 2.15(c), 2.17(b), 2.18(c), 2.23(a) (first part only),  2.25(a,b), 2.28(c),
       2.30(b), 2.31.(c), 2.35

Week 3
We wind up Chapter 2 of the text and begin Chapter 3 on basic modulation
techniques.   Please read Section 2.8.

Homework to be turned in by Friday 9/28/01:
       Probs: 2.38(a,b), 2.40, 2.48, 2.49, 2.50, 2.54, 2.59, 2.61

Week 4
Monday 10/1/01 will be devoted to review.  Recall that the first midterm will be
on Wednesday 10/3/01 and will cover everything in the notes up through
sampling theory.

Week 5
This week we cover linear modulation:  double sideband, single sideband, and AM.
We also cover mixing (frequency translation) and the superhet receiver.

Please read pages 102-113, skipping the last paragraph, then the last paragraph of
page 114 to the last paragraph of page 115, and finally Section 3.1.5, pages 121 - 124.

Homework to be turned in for Chapter 3 is:
      Probs: 3.2, 3.5, 3.9(a), 3.13, 3.15, 3.20, 3.31, 3.36, 3.56, 3.58, 3.59, and 3.60.
      (See earlier for practice problems in this chapter.)

Week 6
We begin angle (phase and frequency) modulation and discuss the narrowband case,
spectra of angle modulated signals,  and the bandwidth of such signals.  We skip
Section 3.2.5 and move on to elementary demodulation techniques.
Read from the bottom of p. 124 to p. 138 then from p. 142 to 146, skipping the
bottom paragraph of p. 146 and the remaining paragraphs of Section 3.2.

Week 7
We cover interference in Section 3.3 focusing on linear modulation and special
cases of angle modulation.  We then cover the phase-locked loop as a feedback
demodulator

Please read pages 147 - 149 up to the paragraph ending after Equation 3.186.
Then read Section 3.4 from p. 154 to 159.

Week 8
This week we started with pulse amplitude modulation, delta modulation, and
elementary pulse code modulation, then we moved on to multiplexing,
both FDM and TDM as well as quadrature multiplexing.  This concludes
Chapter 3, which is the primary basis for the second midterm.

Week 9
This week we cover elements of information theory: measure of information,
entropy (average uncertainty), source encoding techniques, Shannon's
theorem on noiseless channels, discrete memoryless channels, mutual
information, capacity, and Shannon's theorem on noisy channels.

Read Sections 10.1 and 10.2 and do problems 10.2, 10.3, 10.5(a,b only),
and 10.22 to hand in Monday 11/19/01.
On Wednesday 11/21/01 please hand in solutions to problems 10.8, 10.9,
10.23.

Week 10
The topic for the first part of this week is random processes.  Specific
items to focus on are the concepts of stationarity (wide-sense and
strict),  ergodicity, Gaussian distributions, autocorrelation functions
and their properties,  power spectral density (PSD), white noise,  LTI
system input-output relationships: the output is Gaussian if the
input is; the output PSD is the input PSD times the square of the
absolute magnitude of the transfer function.

Read sections 5.1, 5.2.1 - 5.3.3, 5.4.1, 5.4.2  and do problems 5.3, 5.4,
5.5, 5.14 and hand in Monday 12/3/01.

Week 11
This week we cover receiver designs having matched filters.  We
compute probabilities of bit errors in digital communication systems
with ASK, PSK, and FSK modulation.
The last reading/homework assignment:  Please read pp. 329-347,
and skip section 7.2.6.  Then read sections 7.3.1 and 7.3.4; the
notes will have a simplified discussion of BPSK.

Homework problems: 7.1, 7.5, 7.19(a,b,c).  These homeworks do not
need to be turned in.