Well, this post is more of an announcement – I started a YouTube channel and will try to make videos on most of the stuff i can related to Electronics & Communications, and perhaps, some other stuff too. So, to begin with, I decided to go for a set of videos on Communication Systems.

Check out the following videos on PCM, Intersymbol Interference & Eye Patterns. I’ll be posting other videos on the blog wherever required. The best part is that they are light & hence, buffer really fast. Good Luck :)

The first video gives an introduction to how PCM works. The source produces an analog signal which has to be sampled, quantized & encoded to convert it into a pulse composed of only binary words. The binary words, represented by voltage pulses, are then transmitted. It gives a general block diagram of the PCM system.

isi

Intersymbol Interference

Once the signal is transmitted, noise affects the signal and the receiver must remove the additive channel noise. Since, the signal is a set of digital pulses, we only need to re-quantize it to remove noise. We then decode and reconstruct to get the required information(analog). Then, if bandwidth is decreased, we can observe effects of ISI which distorts the signal leading to a CRO pattern that appears to be a closed eye(called eye pattern)