| 摘要 |
A threshold value is set in a decision circuit (9) receiving a transmitted stream of binary symbols from a network link. The decision circuit uses the threshold value for detecting whether a 1 or a 0 is received to produce an output stream having a low bit error rate. Bit errors in the output stream of the detector are detected (35). The number of errors is counted when a transmitted 0 is detected to give a 1 in the output stream. The number of errors is also counted when a transmitted 1 is detected to give a 0 in the output stream. The counted numbers of errors are compared to each other. The threshold value is then modified, if necessary, as given by the result of the comparing, to e.g. make the probabilities of the two kinds of errors equal to each other. Extra predetermined bits can be inserted (31) that are used in determining the bit errors. This method of setting the threshold value gives small bit error rates in the output signal.
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