Lecture diaries at S-72.423 fall 2002

HELSINKI UNIVERSITY OF TECHNOLOGY
COMMUNICATIONS LABORATORY

S-72.423 Telecommunication Systems

Fall 2002

(last update: 27.9.2002)

GUIDE FOR LECTURE DIARIES

General

You will receive email that you should reply to specify your student number, name, course code (S-72.423), and the web address where one can access your own lecture diaries. (Diary format can be in html document or Word document - the first one preferred.) Note: You may protect your diaries by zipping them by passwords you select by yourself. In this case each diary should carry unique password. If you do this, you should email also all of these passwords. See an example of this email here!
This email should be sent at the latest 17.9.2002. If you don't send this email, we consider that you will not participate to writing lecture diaries - module of this course. (Note that the introductory lecture (lecture number 1) on 12.9. is excluded from the lecture diary module.)
After this you will receive mail specifying your student number that is associated with the lecture diaries (name, lecture number, access web page, and possibly passwords to access the diaries) you should grade.
You grade the lecture diaries submitted to you by following the instructions given later in this page. Then you send your grading (should contain text only) to lecture assistant. This mail contains: (1) your student number, (2) the name of the person whose diary you graded, (3) the order number (>=2) and the title of the lecture that you graded, (4) Written arguments (see below for instructions) for your grade, and (5) the grade you consider appropriate for the diary (0-5 points).
In case you can not grade a diary send email to lecture assistant by specifying your name, the name of the diary author and the number of the lecture that was to be graded - course assistant will then handle the grading. Note that in order to get any grade out of this module you must submit and grade at least 8 diaries. If you grade more diaries this will be rewarded as discussed in the homepage.
Note that in your own web page where you have the links to the lecture diaries you have written, and in your diaries only your name should appear - not your student number.

Writing lecture diary

Lecture Diary summarizes the essential elements of a lecture, gives critical view of the discussed topic(s) and points out your own way of understanding. Therefore, its purpose is to develop critical thinking and reassure that you have got a grip what was discussed.

It is strongly recommended that you use library / Web to get more information; especially for the facts you don't understand. You may also discuss the lecture topics at the tutorials.

Don't speculate - give arguments for your statements and observations! The best way to give criticism is to first analyze the current theory (status) and then to suggest a justified and applicable improvement!

A well-done Lecture Diary is also a splendid tool for preparing to exam!

Lecture Diary is also a diagnostic tool: If it appears that you have difficulties in writing it you have not been able to follow the lecture. In this case, try to find the reason as soon as possible!

Note that you probably don't have time to write the diary during the lecture (you make only short notes) but you should write the complete version as soon as possible (when you still remember the lecture).
Familiarize yourself with the example Lecture Diary at the end of this document

In your Lecture Diary you address the following elements:

Contents
Discuss what were the essential elements of this lecture? (Do not copy lecturing slides but use your own words!) Use many figures! You may use Mind Mapping chart to show the logical connections of the lecture topics.

Motivation
Discuss why these concepts and this information is important for science, society and you. Suggest if the studying of this topic could be made more fruitful.

Understanding
Give a critical point of view of a single lecturing topic: How this could be applied, why it should be applied! Discuss what you could not comprehend! How this lecturing topic could be illustrated?

Applications
What is a consequence of this topic with respect of applications? Where and how this topic is applied?

Guide for grading of lecture diaries

Each student participating to the lecture diary - module of this course must grade at least eight lecture diaries. One should read the lecture diary carefully through and justify if it covers the four key points explained in " GUIDE FOR WRITING A LECTURE DIARY "-section.

In your grading you must

Explain what is good in this lecture diary, why?
Explain what is not covered -Suggest how would you make it better!
Give a grade for the lecture diary at the scale 0 - 5p.

Grading of Lecture Diary is always subjective. However, by following the lecture carefully by yourself you enable more justified comments. Return your grade/comments as explained in the " General " section above. See the following example of a Lecture Diary:

LECTURE DIARY 12.9.2002 (example)

Mathew Matts (don't include your student number)

Lecture topic: Exponential Modulation (lecture 2)

Contents: This lecture discussed about exponential modulation that is used for instance in FM-radios. In analysis of FM we noticed that it can not be analyzed as simply as linear modulation techniques. Therefore one must use a set of special cases to find out how it works. This is done gradually such that first narrow band modulation is discussed and then wideband modulation with tones and finally wideband modulation with arbitrary modulation signal. This was used also to determine the required bandwidth. Detection of FM was discussed. It was interesting to note that FM and AM detection carries some similarities as shown in the figure below:

Motivation: Considering EM is important for two reasons. First is gives a set of ideas to analyze non-linear systems. One can see that their analysis is not necessary more difficult than analyzing linear systems but one needs to have a grip how problems can be simplified or to extract the essential elements. Secondly, analyzing EM forms basics to understand phase shift keying modulation, for instance its spectral presentations.

Understanding: In this lecture understanding of FM-AM conversion was interesting. It is a handy way to convert phase changes to amplitude changes for detection. One must use limiters to cut-out channel introduced amplitude distortion. Also channel may introduce FM-AM conversion that is alleviated by equalizer. Therefore, this is an interesting topic having many applications. Also software radio was discussed that I got so interested that I went to the Web and found an interesting article (http://www.nml.org/n_1999-3.htm). Only a brief look revealed that the introduction of A/D conversion can change receiver structure a great deal. However, signal properties are still the same - only their processing is now based on making DSP-based calculations. I wonder if there exists any simulation tools that can be used to study software radios more closely?

Applications: EM is used because it can dramatically improve post detection SNR still this is paid by increased transmission bandwidth. EM is applied in analog radios and in TVs sound channel. Various phase modulation techniques as QPSK and M-PSK are a form of EM. GSM - system applies Gaussian Shift Keying that is a filtered phase modulation technique having narrow bandwidth and smooth envelope. In the web page I found that in modern digital systems, as in satellite or in cellular communications, M-level EM is practically always combined to efficient channel coding as Turbo-coding or concatenated coding.