Advantages of 4D-PAM5 line coding | Disadvantages of 4D-PAM5 line coding
This page covers advantages and disadvantages of 4D-PAM5 encoding. It mentions benefits or advantages of 4D-PAM5 line coding and drawbacks or disadvantages of 4D-PAM5 line coding.
What is 4D-PAM5 line coding?
It is also multilevel signaling scheme.It is called four dimensional five level pulse amplitude modulation scheme. In this encoding scheme, data are transmitted over four wires simultaneously and five voltage levels are used to represent these data viz. -2, -1, 0, 1 and 2. Level '0' is used for forward error detection.
In this technique, all the 8 bits are fed into wire simultaneously and are transmitted using one signal element. Gigabit LANs use this encoding technique to transmit 1 Gbps data over four copper cables which can handle 125 Mbaud.
If we assume that code is just one-dimensional, the four levels create something similar to 8B4Q line coding.
Benefits or advantages of 4D-PAM5 line coding
Following are the benefits or advantages of 4D-PAM5 line coding:
➨As it sends data over four channels, the signal rate is reduced by N/8.
➨It can be used in Gigabit LANs to transmit data simultaneously over four wires.
➨Redundant data is used for error detection.
➨It offers self synchronization.
➨There is no DC components in the encoded signal.
Drawbacks or disadvantages of 4D-PAM5 line coding
Following are the drawbacks or disadvantages of 4D-PAM5 line coding:
➨4D-PAM5 maps 28 data patterns to 44 signal patterns. Hence this coding technique uses lot of redundancy in the signal patterns.
Line coding techniques
Difference between Unipolar Polar and Bipolar coding RZ vs NRZ vs Manchester coding RZ vs NRZ pulse shapes Advantages and disadvantages of NRZ encoding RZ encoding 2B1Q coding 8B6T coding 4D PAM5 coding MLT-3 coding 4B/5B encoding 8B/10B encoding R8ZS scrambling HDB3 scrambling