elements of digital communication

The above figure depicts the elements of a communication system. There are three essential parts of any communication system, the transmitter, transmission channel, and receive..

Advantages - The advantages associate with digital communication systems include (i) A common format for encoding different kinds of message signals (e.g., speech signal, video signal, computer data, etc.) for the purpose of transmission. (ii) An improved security of message. (i..

The concept of information is central to communication. There is no precise definition of the word "information". So, instead of information, we deal with "message..

A digital message is an ordered sequence of symbols selected from a finite set of discrete elements. Examples of digital messages are: (i) letters printed on this page (ii) listing of hourly temperature readings (iii) the keys you press at a computer terminal. Whether..

Satellite Communication - It is mainly done through geostationary satellites. These satellites are fitted with special devices. These devices can receive signals from an Earth station and transmit them again in different directions. These special devices are called transponders. A TV tran..

The 'modem' is a contraction of the term modulator-demodulator. It is a conversion that facilitates the transmission and reception of the data over the public switched telephone network (PSTN). The data of interest may be digital signals generated by computers or service providers. In suc..

The advantages associate with digital communication systems include (i) A common format for encoding different kinds of message signals (e.g., speech signal, video signal, computer data, etc.) for the purpose of transmission. (ii) An improved security of message. (iii) Increase..

. If the mathematical sums do not match, the modems communicate with each other by resending the missing segments of data. Modems also have special circuitry that allows them to compress digital signals before modulating them and then decompressing them after demodulating the si..

The simplest approach to the design of modems is to treat the entire PSTN as a linear analog network. [Note that PSTN is almost entirely due to the use of pulse-code modulation (PCM) for the transmission of voice signals.]..