Q.Write the block diagram of digital communication and explain the function of each block.

A digital communication system encodes the information into binary form, adds channel coding for error protection, modulates it onto a carrier for transmission over the channel, and then reverses these steps at the receiver to recover the original information. …

[!TLDR]

A digital communication system is: information -> source encoder -> channel encoder -> modulator -> channel -> detector -> channel decoder -> source decoder -> information; the receiver reverses each transmitter operation.

The block diagram of a digital communication system and the function of each block are:

1. Information input: the message to be transmitted; the source is generally a computer keyboard or any device producing the information.

2. Source encoder: converts the information into binary code. If the input is an analog waveform it is first converted into a digital (binary) form.

3. Channel encoder: generates the channel code word from the source code words. It adds controlled redundancy and changes troublesome bit patterns so that errors introduced by the channel can be detected and corrected.

4. Modulator: modulates the channel code words onto a continuous (carrier) wave suitable for transmission over the channel.

5. Channel: the physical medium (wire, cable, free space) through which the modulated signal travels from transmitter to receiver.

6. Detector (demodulator): demodulates the received continuous waveform and converts it back into the digital (ordinary) signal.

7. Channel decoder: decodes the channel code word, using the redundancy added by the channel encoder to detect and correct errors.

8. Source decoder: converts the channel-decoder output back into the original information signal.

9. Information output: delivers the recovered information to the destination. …