07-10-2010, 11:19 AM
ABSTRACT
The present need to access internet in homes, offices, companies etc in affordable way results in selection of efficient technology and as a result cable modems are used. Cable modem technology brings high-speed broadband networking to desired places through cable television lines. Cable modems are devices that allow high-speed access to information at a distant server may it be Internet server or video on demand server, via a cable television network. While similar to the traditional (analog) dialup modems, a cable modem is significantly more powerful, capable of delivering data approximately 500 times faster. This not only gave subscribers an opportunity to experience new level of speeds of browsing the net but also eventually make it affordable.
The Tele Vision signals are usually spread in the 50 MHz to 750 MHz spectrum. With each TV Channel such as CNN, BBC, and CNBC occupy 6MHz. Similarly the Internet services via the cable (downstream and upstream separately) occupy a 6 MHz channel too.
The paper further discusses the following topics on the subject of cable modems: working, the factors based on which the cable modem speed varies, traditional cable system, hybrid fiber coaxial system, types of cable modems, external cable modem, internal cable modem, and interactive set-top box. Inside the cable modem, tuner, demodulator, burst modulator, MAC (Media Access Control), interface and CPU.