What are the hdb3 encoding rules?

The encoding rules are: 1. If the previous encoding is 0 and the current data bit is 0, the encoding is 0; 2. If the previous encoding is 0 and the current data bit is 1, the encoding is bipolar. Pulse (A or -A), and add 1 to the counter; 3. If the previous code is 1, and the current data bit is 1, then the code is 0, and the counter will be incremented by 1; 4. If the previous code is 1, the current data bit If the data bit is 0, the encoding method is determined according to the parity of the counter. If it is an even number, the encoding is (B or -B). If it is an odd number, the encoding is zero level and the counter is cleared and so on.

# Operating system for this tutorial: Windows 10 system, Dell G3 computer.

HDB3 (High Density Bipolar 3-zero) is a high-density bipolar 3-zero encoding rule that is widely used in digital communication systems. It is a line encoding technology based on bipolar signals that is used to convert digital signals into voltage signals for transmission. HDB3 encoding rules achieve data transmission and synchronization by inserting special encoding sequences into signals.

The main purpose of HDB3 encoding rules is to solve the DC offset problem in transmission lines. During transmission, signals may be subject to various interferences and distortions, one of which is DC offset. DC offset means that the DC component in the signal exceeds the normal range, causing the receiving end to be unable to decode it correctly. In order to solve this problem, the HDB3 encoding rules use a special encoding method, which inserts zero levels into the signal.

The basic principle of HDB3 encoding rules is to encode each 1-bit data as a bipolar pulse, and insert zero levels as needed to maintain DC balance. The specific encoding rules are as follows:

1. If the previous encoding is 0 and the current data bit is 0, the encoding is 0;

2. If the previous encoding is 0, the current data bit is 1, the encoding is bipolar pulse (A or -A), and the counter is increased by 1;

3. If the previous encoding is 1 and the current data bit is 1, the encoding is 0, and the The counter increases by 1;

4. If the previous encoding is 1 and the current data bit is 0, the encoding method is determined based on the parity of the counter:

a. If the counter is an even number, then Encoded as bipolar pulse (B or -B);

b. If the counter is an odd number, the encoding is zero level and the counter is cleared.

Through this encoding rule, HDB3 can effectively solve the DC offset problem and maintain the DC balance of the transmission line. At the same time, due to the insertion of zero levels, HDB3 encoding rules can also provide clock synchronization functions so that the receiving end can correctly decode data.

HDB3 encoding rules are widely used in digital communication systems. It is used in a variety of transmission media, including fiber optics, coaxial cables, and copper wires. In systems with higher transmission rates, HDB3 coding rules can provide better transmission performance and anti-interference capabilities.

Summary

HDB3 coding rule is a high-density bipolar 3-zero coding rule used to solve the DC offset problem in transmission lines. It achieves data transmission and synchronization by inserting special coding sequences. HDB3 coding rules are widely used in digital communication systems and can provide better transmission performance and anti-interference capabilities

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