arjun chandra

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1. The Talking Drums

2. Too Many Beats (Redundancy) Keeps the Message Alive

3. Redundancy in Language

4. Redundancy in Digital Communication

4. Redundancy in Digital Communication

Claude Shannon played such games in the 1940s, but there was no internet at the time, so no blogs either. He used books, and through playing such games and analysing language mathematically, made digital communication a reality. He invented a measure for information. Now we could measure how many 'bits' of information a message contains, like we could measure how many grams of sugar a pack of sugar contains.

Central to the idea of communicating messages is the presence of a the 'medium' through which the message travels from sender to receiver. Our messages are represented as a stream of bits, [0]s and [1]s, and sent as electrical signals over cables or electromagnetic waves over wifi. Many things can corrupt a message as it is on its way, e.g. cabling problems, network issues. The medium is noisy. Our computers and mobile phones still let us communicate reliably. How do they do it?

Yes, they do it by adding extra symbols to our messages, extra [0]s and [1]s. This was possible to figure out because of Claude Shannon's work. We could now understand how many bits of information a message contained. Likewise, how many extra bits makes a message wordy enough to recover the information in it, if it gets corrupted by noise while it is on its way.

When a drummer drums 'the lion makes a funky king' as [_----__-], as long as the neighbouring village is able to hear most of the message, say [_??--__-], they would figure out that its the 'lion' we are talking about, for who else would make a funky king? Similarly, if our digital message were [0 1 0] and we substitute [000] for any [0] and [111] for any [1], our message would become [000 111 000]. We can design our receiver to detect patterns: at least two [0]s in sequence of three digits to mean [0] and at least two [1]s to mean a [1]. In so doing, we would recover from errors that corrupt the message to [100 011 010].

Padding messages with extra symbols, not only removes confusion, it helps overcome errors introduced by thunderstorms in case of drummers, or network errors in case of our WhatsApp messages. Redundancy helped centuries ago with drums, and continues to do so today with computers and mobile phones.