Telecommunications Articles

A good article on BER is available here. Other good telecommunication articles from the same website are:Selected Comments on Scrambler Security, Analog Tone Detection using the Quadrature Receiver, and Digital Phase Modulation

Thoughts on my favorite software tools

Vim is the excellent cross-platform editor that lets me achieve dhyana(Zen) while programming.

Preparing documents with LaTeX (using Vim of course) similarly lets me concentrate on my task without worrying about the irritating formatting details while composing.

To be quite honest, after I have gotten used to these two tools, I feel cramped and inefficient whenever I have to use a non-modal editor or a WYSIWYG(“What is see is what you get”) editor like Word.

By the way, for those who don’t want to jump in head-first into LaTeX, LaTeXiT is an excellent app for generating image files that can be put inside Word documents, etc.

Exploring Analog QAM modulation with Grapher

Caveat: This is NOT meant to be a rigorous explanation of QAM. You can read a book like Telecommunication Breakdown or Principles of Communications by Ziemer and Tranter for such explanations(of course, Wikipedia also works at times). These three plots are just meant to build intuition.

Note: Message signals in general are NOT sinusoids! (sin(x) or cos(x))

Enjoy. Click on the thumbnails to enlarge the graphs. Of course, there is no noise effect and no demodulator plots shown here.

First step: y = sin(x)*sin(50x)

Second step: y = cos(x)*cos(50x)

Third step: y = sin(x)*sin(50x) + cos(x)*cos(50x)

A quick way to make screencaptures is to press Apple-Shift-3(the screenshot will be put on the Desktop)