What is Data Transmission and explain Transmission Channels

Data Transmission
Transmission of the data is very much important in the services related to the data communication and the information technology as this technique makes use of the data processed in the order to forward the same to the end user.
The communication of the data mainly involves the processing of the data as well as the transmission of the data and for the communication of the data, following devices play a very critical role and these devices should work in a very efficient manner.

1. Transmitter
2. Converter at the transmitting end.
3. Transmission channel.
4. Converter at the receiving end.
5. Receiver.

Transmission signals –
The telecommunication systems help in the transmission of the data and this data is then transmitted in the form of the electromagnetic signals.

The types of these signals can be categorized as the follows –
1. The Analog Signal –

a. Is a continuous wave form.
b. Passes through the communication medium.
c. Used mainly for the transmission of the data in the form of the voice and to reflect the various variations in the pitch, across the line.
d. The wave form is of different frequencies and subject to the distortion.
e. The main characteristics of the wave form are as follows –

A. Amplitude – refers to the strength of the signal.
B. Phase – refers to the direction of the flow of the signal in a cycle time.
C. Frequency – refers to the number of the times the wave form is repeated during a specified interval.

2. The Digital Signal –

a. Is a discrete wave form.
b. Transmits the data coded into the two discrete states as 1 – bits and 0 – bits, which are represented as the on – off electrical pulses.
c. Generated by the micro – processor based – or controlled – device.
d. Possesses identical strength from the source to the destination.
e. Is very clear, rapid and also is distortion – free.
f. Less prone to noise – distortion.

Modem
Modem refers to Modulation / DEModulation. Modem is a device used in the translation from the analog signal to the digital signal or from the digital signal to the analog signal.

Transmission Channels
Transmission channels are generally referred to as the communication channels and these act as the links, which help in the transmission of the data from one device in a particular network to the other. A transmission channel has the ability to make use of the various types of the media like the following –
1. Physical connection lines –

a. Twisted pair of the copper wires.
b. Coaxial cables.
c. Optical fiber.

2. Micro – wave lines –

a. ‘Line of sight’ earth micro wave (from tower to the tower)
b. Radio/wire – less transmission waves (AM/FM)
c. Satellite

Basic critical features of the communication channels –
1. Transmission Speed: Also called as the Baud Rate and it refers to the total amount of the information which can be transmitted through any type of the telecommunication channel. Transmission speed can be measured in terms of the Bits per Second.

2. Band – width: The capacity of the communications channel as measured by the difference between the highest and the lowest frequencies that can be transmitted by that channel is referred to as the band – width.

3. Transmission Modes: The various modes affecting the transmission may involve the Asynchronous Transmission and the Synchronous Transmission. In asynchronous transmission, transmission of only one character takes place at a time and this type of the process is generally used for the low speed transmission but in case of the synchronous transmission, a group of the characters is transmitted simultaneously and is often used for the high speed transmission of the block of the characters.

4. Transmission Direction: The transmission of the data can take place in the different directions with the help of the simplex, the half duplex or the full duplex transmission.

5. Communication Processors: Transmission of the data and then the reception in a telecommunication network can be done with the help of the certain processors, some examples of the processors can be summarized as the follows –

a. Front End Processors
b. Concentrator
c. Controller
d. Multiplexer
e. Telecommunication Software