Data slicer, data slicing method, and amplitude evaluation value setting method

An amplitude evaluation value setting method comprising:

• providing an amplitude evaluation value setting unit including an error count circuit and a controller;
• a start value setting step of setting a start value at an amplitude evaluation value for determining whether an input signal including data which are transmitted in serial is a desired signal or not, the start value being set by the controller;
• outputting the start value to a slice level calculation unit including at least an amplitude evaluation circuit and a CRI evaluation circuit;
• a signal detection step of evaluating an amplitude of the input signal on the basis of the amplitude evaluation value in a predetermined period, thereby detecting the desired signal, the amplitude of the input signal being evaluated by at least one of the amplitude evaluation circuit and the CRI evaluation circuit;
• a slice level data calculation step of, when detecting the desired signal, calculating slice level data for binarizing the input signal, on the basis of the detected desired signal;
• outputting the input signal and slice level data to a data slicing unit including a binarization circuit;
• a binarization step of binarizing the input signal using the slice level data, to be converted into a binarized signal;
• outputting the binarized signal to a decoding circuit;
• a decoding step of decoding serial data which are extracted from the binarized signal, thereby generating decoded data;
• outputting the decoded data to a data selection unit including an error detection circuit:
• detecting errors in the decoded data;
• outputting the an error detection signal from the error detection circuit of the data selection unit to an error count circuit of the amplitude evaluation value setting unit;
• an error count step of counting errors in the decoded data, and storing the amplitude evaluation value and the number of errors;
• outputting (1) the counted errors from the error count circuit and (2) the input signal to the controller of the amplitude evaluation value setting unit;
• an amplitude evaluation value update step of binarizing and decoding the input signal and counting counted errors in the decoded data during a predetermined period, thereafter subjecting the amplitude evaluation value to an arithmetic process using a predetermined step value, so as to approach an end value, and updating the amplitude evaluation value;
• and
• an amplitude evaluation value selection step of selecting an amplitude evaluation value that minimizes the number of errors as an optimum amplitude evaluation value, on the basis of the numbers of errors at various amplitude evaluation values, which are obtained by changing the amplitude evaluation value in the predetermined step value from the start value to the end value.