Block Diagram Of Communication System 81v6m

Block Diagram of Communication System:

Transmitter & Encoder: Transmitter is the first block in the block diagram of communication system. Here the message which is to be sent is generated. This message is sent to encoder. Encoder is the second block in the block diagram of communication system. This block performs encoding. it is the process in which the actual message is converted in to symbols for transmission. In this a sequence of characters are put in a specialized format for efficient transmission. If you transmit a message without encoding then there may be a chance of other persons trapping the message by knowing the frequency of transmission. But if you transmit it through encoding even though they trap it they can’t decode. Only the person who knows how it is encoded can decode it. This is done to increase the security.

Noisy Channel: This is the third block in the block diagram of communication system. Noisy channel is nothing but the medium through which the message is transmitted. Messages are conveyed through this channel. Different channels have different strengths and weaknesses. Each channel has its own frequency and different applications have different operating frequencies. For example mobile communications operate in the vicinity of 800 MHZ and FM radio operates in the vicinity of 100 MHZ.

Decoder: This is the fourth block in the block diagram of communication system. Decoder is used to decode the encoded message and retrieve the actual message. Decoding must be done correctly. If this part is not performed well then the message which is received might not be correct. As i said earlier the person who knows how to encode can only do the decoding.

Receiver: This is the final block in block diagram of communication system. This can be said as the target to which the information needs to be delivered. In the above example American army is the transmitter and the tanker is the receiver.

Two forms of data movement: 1. Parallel Transmission: Parallel data transmission involves the concurrent flow of bits of data through separate communications lines. This pattern resembles the flow of automobile traffic on a multilane highway. Internal transfer of binary data in a computer uses a parallel mode. If the computer uses a 32-bit internal structure, all the 32 bits of data are transferred simultaneously on 32 lane connections. Parallel data transmission is commonly used for interactions between a computer and its printing unit. The printer usually located close to the computer, because parallel cables need many wires and may not work stably in long distance. 2. Serial Data Transmission: Most data transmitted over telephone lines use a serial pattern. That is, each individual bit of information travels along its own communications path; the bits flow in a continuous stream along the communications channel. This pattern is analogous to the flow of traffic down a one-lane residential street. Serial transmission is typically slower than parallel transmission, because data are sent sequentially in a bit-by-bit fashion.