5 Project 5: Introduce Noise into digital data and digital signals:
As we know that noise can be occurred while transmitting data in both forms analog and digital. Additionally, noise and error can interfere, copper-based media, satellite and fibre optic cable, however, in fibre optic it has less chances of noise then other type of media. These type of error and noise can be seen in transmission system.
White noise, also knows by thermal or Guassian noise. Mostly this noise can be found in radio transmissions and electronic devices. And it rely on temperature, this noise is constant. Thus, it can be reduce to large extent but impossible to remove completely. And it fuzzier the ...view middle of the document...
And it make irregularities in timing during transmission of digital signal. Further, jitter slow down the system and it’s kind of cyber-attack.
There are many kind of noises and error exist during transmission of signal which slow down the system. Thus, they can be prevented by taking such measures;
• Proper shielded cables can reduce electromagnetic interference and crosstalk.
• Replace old devices with new modern digital devices.
• Proper network and building infrastructure should be build. For instance, heavy lights and aluminium door and windows should not be used. (White, 2002, p. 173-177).
6 Project 6: Digital Encoding Schemes:
Digital encoding scheme mainly use to change the 0s and 1 of digital data into the proper transmission forms. And below picture will show all five digital encoding schemes:
None-Return to Digital Encoding Scheme:
This digital encoding scheme transfer 1s as 0 voltage and 0s as positive voltage. And it is very easy to produce and implementation on hardware is very cheap. In this scheme receiver has to check voltage level for every bit to decide the bit is 0 or a 1. It also has some disadvantages, in 0s long distance data does not change the signal, and therefore, receiver cannot recognize that when one bit ends and another start.
Non-Return to Zero Inverted:
In this scheme voltage change at the start of 1 and does not change at the 0. And in this scheme receiver has to check that does any changing happen at the start of the bit to know if it is a 0 or 1.
Manchester Digital Encoding Scheme:
This encoding scheme assure that every bi has some sort of signal change and it solve the synchronization issue as well. This encoding has following properties: to transmit a 0, the signal change from high to low in the middle of interval; to transmit a 1, the signal change from low to high in the middle of interval.
The Differential Manchester:
This scheme mostly used in a local area network to transmit digital data through a local area network cable. And it is similar to Manchester Scheme, however, the difference in this scheme is the transmission in the middle cannot distinguished between 0 and 1. The advantage of this scheme is transition always occur in the middle of the bit. Therefore, the receiver can easily recognized the signal change at regular interval and the incoming bit stream can be synchronized. And this scheme is self-clocking because it works in same manner as clock ticks works. The disadvantage of Manchester Scheme is signal has to change two time of each bit one at the beginning and in the middle too.
Bipolar-AMI Encoding Scheme:
This scheme is distinct from all encoding scheme because it uses three voltage levels. At the point transmits a binary 0, a 0 voltage is transmitted. Another, when device transmits a binary 1, either a positive or negative voltage transmitted. Both depend on the binary 1 value which has been last transmitted. (White, 2002, p. 42-45).