Write a short note on Pulse Code Modulation.

1. The process of encoding digital information in terms of voltage signals is called modulation.
2. It is done using device called modulator.
3. The reverse process of decoding the signal back to the digital information is called demodulation and it is done by de-modulator.
4. The voltage signal is called carrier signal.
5. Formally modulation is a process of varying carrier signal for conveying certain information.
6. In analog modulation the change applied continuously to the signal
7. In Digital modulation the changes are applied in discrete steps.

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