DATA TRANSMISSIONWHAT IS DATA TRANSMISSION??
- Data transmission is the transfer of data from point-to-point often represented as an electro-magnetic signal over a physical point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibers, wireless communication channels, and storage media. The term usually refers to digital communications (i.e. digital bit stream), but may include analog data transmission as well.
- Data transmission is a subset of the field of data communications, which also includes computer networking or computer communication applications and networking protocols, for example routing and switching.
# this chapter is easy to understand becoz all of us has a basic understanding about this chapter.
types of data transmission are ::
1. Analog vs Digital
-Analog transmission uses signals that are exact replicas of a sound wave or
image.
-Signals of varying frequency or amplitude are added to carrier waves with a given frequency of
electromagnetic current to produce a continuous electric wave.
-E.g standard phones, fax machines, and modems.
- Digital transmission the signals are converted into a binary code, which consists of two elements.
2. Bandwidth
(1) A range within a band of frequencies or wavelengths.
(2) The amount of data that can be transmitted in a fixed amount of time. For digital devices, the bandwidth is usually expressed in bits per second (bps) orbytes per second. For analog devices, the bandwidth is expressed in cycles per second, or Hertz (Hz).
The bandwidth is particularly important for I/O devices. For example, a fast disk drive can be hampered by a bus with a low bandwidth. This is the main reason that new buses, such as AGP, have been developed for the PC.
3. Series vs Parallel transmission
*There are 2 method of transmitting data either in SERIES or PARALLEL.
SERIES
-
is the process of Transmitting binary words a bit at a time. - Much simpler and less expensive.
- Very slow method of data transmission
- Serial data transmission is useful in systems where high speed is not requirement.
- Are widely used in transmitting data between a computer and its peripheral units
- Use for short communication
- All bits of binary data are transmitted simultaneously.
- Use within computer components
- Disadvantage : Large number of interconnecting cable between the two units. : Cabling become complex and expensive
- Long multiwire cables are require minimiza noise and distortion problem.
• Synchronous transmission
– Data organised into blocks or groups and
transferred at regular specified interval
• Asynchronous transmission
-the process where transmitted data is encoded with start and stop bits, specifying the beginning and end of each character.
- Data sent without being synchronised
• Isochronous transmission
-data is sent at the same time as other related data to support certain types of real time applications e.g streaming voice, video and music.
5. Transmission Direction
• Simplex
• Duplex
– Half Duplex
– Full Duplex
# OK guys, with this video, u can completely understand about this TRANSMISSION DIRECTION . ;D
6. Circuit switched, Packet-switched, and Broadcast Connection.
Circuit switched
– Data used dedicated path from sender to receiver
Packet switched
• Data sent as individual packets, which are assembled at the recipient’s destination
Broadcast Coneection
# example for broadcast connection
-Data broadcast to all nodes within range
ENJOY READING FRIENDS ! ;')
