What are data encoding and modulation?

What are data encoding and modulation? How do they differ from one another?

Thank you sir, for giving answer for this question. I was also having the same question in my mind to ask you. but my friend asked you, any way i am happy to see this kind of discussions in future also.

Often data is encoded - each data item is represented by a code.

Examples :

* Each item in a supermarket is coded by a barcode number.
* Each book in a library has an ISBN number.
* Each branch of each High Street Bank has an individual branch sort code
Eg. 51-81-26
* Each pupil's gender is recorded on a school's database as 'M' for male or 'F' for female.
* Country codes for Olympic athletes may be GB, US, F etc..

When the data is input, the codes are used.

Difference between encoding and modulation:

Encoding: The way in which the computer data is represented is known as encoding, there are several encoding techniques (Unipolar, Bipolar and Biphase).


Modulation: Modulation is the method of changing some of the characteristics of the message signal so that it can be transmitted to comparatively large distance without(least) getting affected by noise or unwanted signals.