What is Manchester Encoding?

Manchester code, also known as digital bidirectional code, phase separation code or phase coding (PE), is one of the commonly used binary code line coding methods. It is used by the physical layer to encode the clock of a synchronous bit stream. And data. In communication technology, a code used to indicate that the data in the bit stream to be transmitted is combined with a timing signal. Commonly used in Ethernet communication, train bus control, industrial bus and other fields. ^[1]

In Manchester encoding, there is a transition in the middle of each bit.

There is ambiguity about the above level transitions: Regarding Manchester coding level transitions, Lei Zhenjia's "

The Manchester coding algorithm is mainly used for signal preprocessing. The algorithm needs to initially estimate the number of signal sources and establish a noise model. The number of information sources K can be estimated using the Minimum Description Length (MDL) criterion. This algorithm can effectively estimate the number of information sources from the perspective of information theory. Meanwhile, the noise matrix N =

, Each vector obeys zero mean, and the variance is

The white complex Gaussian distribution is independent of each other, and the noise and the source are independent of each other. The Manchester coding algorithm first needs to preprocess the sorting signals during operation, and through preprocessing, the dimension is equal to the number K of response signals. Manchester encoding characteristics

The separation matrix W can be solved by transforming the joint diagonalization formula to solve the problem. Finally, the separation matrix W can be obtained by solving the asymmetric non-orthogonal joint diagonalization problem. ^[4]

Commonly used Manchester encoding methods are: Using a dedicated Manchester codec, using high speed

Due to the mid-time of each symbol of Manchester encoding, a level transition occurs. This is very advantageous for the receiver to extract the bit synchronization signal. But we can see the other

Manchester Coded Interval Reading

Read data through the timer control at regular intervals. Because only the first 0.5T data is valid, and the last 0.5T data is not valid. So when reading the data, just read the data of 0-0.5T. This method is mainly done by reading the data intermittently with a timer. In view of the occurrence of the skip phenomenon, the solution is to avoid the skip point by delay, so that the data can be effectively read out. ^[5]

Manchester coded continuous detection

The so-called continuous detection method is for the interval reading method mentioned above. This method is not reading data at intervals. Instead, it has been monitoring the level change, and then judges whether the current data is "l" or "0" by the length of time that the waveform maintains high and low levels and the ordered combination of high and low levels. ^[5]