Can any one tell about pulce code modulation(pcm)?

Question

Can any one tell about pulce code modulation(pcm)?

Answer 1

Pulse Code Modulation (PCM) is the preffered method of communications within specially the public switched telephone network to combine digitized voice and digital data into a single, high speed digital signal and propagate it over either metallic or optical fiber cables and the process is much easier as compared to other techniques of modulation. In fact PCM is the only digitally encoded modulation technique that is commonly used for digital transmission.

In case of PCM, the pulses are of fixed lengths and fixed magnitudes. It's a binary system where a pulse or lack of a pulse within a prescribed time slot represents either a logic 1 or a logic 0 condition.