ELEC 3400 - Communication Systems - Fall 2009

Instructor: Dr. Shiwen Mao

Course website: http://www.eng.auburn.edu/~szm0001/ELEC3400-F09/

Textbook:

• S. Haykin and M. Moher, Communication Systems, 5th Ed., John Wiley & Sons, Inc., June 2009.

Reference book:

• B. P. Lathi and Z. Ding, Modern Digital and Analog Communication Systems, 4th Ed., Oxford University Press, Jan. 2009.

Syllabus: PDF

Questions & answers:

• Click here (last updated: Nov.11, 2009)

Class room & hour: Broun 125, Tuesday and Thursday, 11:00-12:15.

Office hour: WF 14:00-15:00, drop by my office (Broun 301) any time, or email for appointment

Final exam hours: Thursday, December 10, 12:00- 14:30, according to AU Exam Schedules

Aug. 17, 2009, Monday

• Welcome!

Aug. 19, 2009, Wednesday

• Reading assignment: Chapters 1 "Introduction" and 2 "Representation of Signals and Systems." Chapter 2 is a nice and neat summarization of the ELEC 2120 material, which we will use a lot through out this semester. It is very important to refresh your memory to understand the ELEC 3400 material.
• I have sent the slides for Tuesday's lecture to the class via email. If you have not received it, please contact me.
• We will discuss Chapter 3 "Amplitude Modulation" tomorrow.

Aug. 23, 2009, Sunday

• Sorry for the delay in posting the first homework problems. It took me more time to prepare the slides for Chapter 3. I will post the problems soon and the hw is due Sept. 1.

Aug. 24, 2009, Monday

• Homework assignment 1: Problems 2.3 2.12 3.5, 3.17, and 3.24 in the textbook. It is due Tuesday Sept. 1, before the class. The problems can be downloaded here.
• I have sent the slides for Chapter 3 to the class via email.
• In addition to Chapter 2, a useful overview of Fourier transform can be found at http://en.wikipedia.org/wiki/Fourier_transform.

Aug. 27, 2009, Thursday

• Extension for Homework assignment 1: due Thursday Sept. 3, before the class. The last problem involves materials that we will discuss next Tuesday.
• Check the Wikipedia page for more information on even and odd functions: http://en.wikipedia.org/wiki/Even_and_odd_functions.

Sept. 1, 2009, Tuesday

• Just found that there is a meeting with the Provost tomorrow (Wednesday) from 3:00pm that I have to attend. The meeting probably will last for one hour.  I will also be available this afternoon from 3:30pm to 5:00pm.
• The definition of sgn(t) is given in Eqn.(2.18), Page 16 of the textbook. The derivation for the Fourier transform of the sgn(t) function is given in Page 36 of the textbook. For homework Problem 2.12, you also need to apply the Duality property of Fourier transforms in Page 18. 

Sept. 2, 2009, Wednesday

• Based on request, there is a further extension of homework 1. It is now due Tuesday Sept. 8, before the class. I will discuss some hints for the problems tomorrow.
• We will have our second homework assignment tomorrow. 

Sept. 3, 2009, Thursday

• Homework assignment 2: Problems 3.3(a), 3.4(a)(c), 3.7, 3.9, 3.10, and 3.11 in the textbook. It is due Thursday Sept. 10, before the class. The problems can be downloaded here.

Sept. 8, 2009, Tuesday

• We will discuss homework 1 solution today. If time permits, I will also discuss some other example problems.
• This is the H1N1 contingency statement as required by the provost:

        If normal class and/or lab activities are disrupted due to a high number of students experiencing illness or an emergency or crisis situation (such as a widespread H1N1 flu outbreak), the syllabus and other course plans and assignments may be modified to allow completion of the course. If this occurs, an addendum to your syllabus and/or course assignments will replace the original materials.

Sept. 13, 2009, Sunday

• The slides for Chapter 4 has been distributed to the class via email. Let me know if you did not receive it. You can also bring a memory key to the class to get a copy if email does not work for you.
• Homework assignment 3: Problems 4.4(a)(b), 4.5(a), 4.7, 4.9, 4.10 in the textbook. It is due Tuesday Sept. 22, before the class. This is a hard deadline, since I will discuss the solution in the Tuesday class. The problems can also be downloaded here.
• Reminder: our first midterm exam will be on Thursday Sept. 24, 11:00am~12:15pm, BR 125. Chapter 3 and 4 will be covered. Feel free to see me if you need any help with the material.

Sept. 15, 2009, Tuesday

• I will be out of town for a conference in Canada and will leave 3:30pm next Tuesday. So please see me early if you want to discuss the homework problems or the course materials.
• I will discuss homeworks 2 and 3 in next Tuesday class.
• Hints for Homework 3:

o Problem 4.4: the envelop of a signal s(t)=a(t)*cos(2πfct)+b(t)*sin(2πfct) is: e(t)=sqrt(a²(t)+b²(t)). That is, the square root of of the square sum of the coefficiencies of cos() and sin().

o  Problem 4.5(a): for small x, cos(x)≈1, and sin(x)≈x. Follow the derivations in Equations (4.17)~(4.20).

o  Problem 4.7: follow the derivations in Equations (4.17)~(4.20)

o  Problem 4.9: see Example 4.3 in Pages 116, 117.

o  Problem 4.10: see Example 4.4 in Page 119.

Sept. 16, 2009, Tuesday

• Additional office hours:  I will be out of town after the next Tuesday class. I will discuss homeworks 2 and 3 in that class. While I am away, I have arranged my graduate student, Mr. Donglin Hu, for office hours next Wednesday Sept. 23, 2:00pm~4:00pm. He will be in his office BR 163 to answer any questions you may have regarding homework 3 during these two hours.

Sept. 18, 2009, Thursday

• URGENT: Change of Schedule: based on request, our first midterm exam will be on Tuesday Sept. 29, 2009. I will wrap up Chapter 4 in the next Tuesday class (Sept. 22), and my graduate student In-Keun Son will teach the Thursday class (Sept. 24) to discuss homework solutions. I will be available Monday Sept. 28 to answer additional questions that you may have.
• Extension for Homework 3: Homework 3 is now due Thursday, Sept. 24, before the class. This is a hard deadline with no further extensions, since the solutions will be discussed in the Thursday class.

Oct. 7, 2009, Wednesday

• We will use a little bit of probability theory in Chapter 7. Specifically, when deriving the quantization error, we use the uniform distribution and driving the variance of a uniformly distributed random variable, the quantization error. A handout on basic/minimal probability theory and examples has been sent to the class through email. Let me know if you have not got it.
• We will have our fourth homework assignment tomorrow.

Oct. 8, 2009, Thursday

• Homework assignment 4: including 3 warm up exercises, 3 regular problems, and one MATLAB exercise. The MATLAB exercise is optional. The problems can be downloaded here. HW4 is due Oct. 15, Thursday, before the class. 

Oct. 13, 2009, Tuesday

• Which problems are due this Thursday?  Both the warm-up problems and the regular problems are due on Thursday. The MATLAB problem is optional and is not required.
• Hint for the third regular problem: We discussed the relation between the number of quantization levels L and the number of bits R used to represent a level in class. That is, R=log2(L). You know how many samples you get per second by applying the Nyquist theorem, and now you know how many bits you get for each sample. The produce of the two gives the bit rate of the PCM signal.
• Homework assignment 5: including 3 warm up exercises, 3 regular problems 7.13, 7.14, and 7.17, and 1 optional MATLAB exercise 7.24. The problems can be downloaded here. HW5 is due Oct. 20, Tuesday, before the class.

Oct. 19, 2009, Monday

• Question about Homework 5:
  • Question: In Problem 7.14, there are two equations to find L: i) step = (2*max(m))/L; yields L = 12.  ii) R = log2(L); yields L = 16. Which one is correct?
  • Answer: L=12 is the correct one. The second formula is for the maximum value of L. The first formula is always correct if you know the step size and the maximum range max(m). In this problem, apparently, L=12. When coding the L=12 levels, three bits are not sufficient (with only 8 different combinations of three-digits, each being either 0 or 1). So we have to use 4 bits to code the 12 levels. When 4 bits are used, some combinations (actually 4 combinations of 4 digits) are not used.

Oct. 20, 2009, Tuesday

• Homework assignment 6: including 3 warm up exercises, 3 regular problems, and one MATLAB exercise. The MATLAB exercise is optional. The problems can be downloaded here. HW6 is due Oct. 27, Tuesday (firm deadline), before the class.  I will discuss the solutions in that Tuesday class.
• REMINDER: our second midterm exam is on Thursday, Oct. 29, in the same classroom, regular class hour. Please mark your calendar. Since it is in regular class hour, make up exams will generally not be provided unless sickness or other emergencies (let me know at least one day before the exam). To be fair to all the students, a make up exam may be a little bit more difficult than the regular exam. 

Oct. 22, 2009, Thursday

• HW5 solutions has been distributed via email.
• For HW6, Problems 8.6 and 8.8 are not required since we have not discuss the related material in class yet. We will get back to these two problems after the midterm exam.

Nov. 5, 2009, Thursday

• Our arrangement for the last two classes:
  • Dec. 1, Tuesday: guest lecture by Mr. Sperby Piner.  He is an Auburn graduate and an network engineer working for AdTran, a Huntsville-based telecommunication company. He will talk about a brief history of telecommunication, current industrial practice, and job opportunities.
  • Dec. 3, Thursday: a presentation by Mr. Paul Temple about some modulation techniques used in Neptune products, a presentation by Mr. Peter Farver about a modulation/demodulation project he is working on, and a presentation by Dr. Yihan Li, about a wireless networking project for search and rescue.
• The final exam is on Thursday, December 10, 12:00- 14:30 in BR 125.

• Homework assignment 7: including 3 warm up exercises, 3 textbook problems, and one MATLAB exercise. The MATLAB exercise is optional. The problems can be downloaded here. HW7 is due Nov. 12, Thursday, before the class.
• HINT for Problem 8.8: First write the BER P_e as a function of p₀, p₁,  f_Y(y|0) and  f_Y(y|1). The two conditional probabilities are both function of the threshold λ. Then set the first derivative of P_e with respect to λ to 0, to find the expression for the optimal threshold value. 

• Two typos in the textbook
  • Equation (8.23): the correct form should be

      .

  • Equation (8.39): the correct form should be

    

Nov. 5, 2009, Thursday

• Homework assignment 8: including 2 warm up exercises, textbook problems 9.1, 9.4, 9.7(a)(b), 9.8, and one MATLAB exercise. The MATLAB exercise is optional. The problems can be downloaded here. HW8 is due Nov. 19, Thursday, before the class.

Nov. 17, 2009, Tuesday

• Homework assignment 9: including 2 warm up exercises, textbook problems 9.11, 9.12, 9.15, and one MATLAB exercise. The MATLAB exercise is optional. The problems can be downloaded here. HW9 is due Dec. 3, Thursday, before the class.