Patent ID: 11870489
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Telecommunications (Electrical engineering)
Classification: CPC H | IPC H

Claim 6:
7. An adaptive filter circuit, comprising:
a filter unit that filters a received signal on the basis of a filter coefficient;
a tentative decision unit that makes a tentative decision for symbols on the basis of the received signal that has been filtered and a decision threshold, and outputs a tentative decision signal including a sequence of the symbols; and
a filter coefficient updating unit that, on the basis of the received signal, the received signal that has been filtered, and the tentative decision signal output by the tentative decision unit, calculates an update value for the filter coefficient, and provides the update value for the filter coefficient that has been calculated to the filter unit,
wherein on the basis of the received signal that has been filtered and has been increased or reduced by the scale value used when the SN ratio estimation circuit according to claim 1 takes in the received signal that has been filtered instead of the received signal and calculates the SN ratio, and the decision threshold, or on the basis of the decision threshold to which the threshold change rate used when calculating the SN ratio is applied and the received signal that has been filtered, the tentative decision unit of the adaptive filter circuit makes a tentative decision for the symbols, and outputs a tentative decision signal including a sequence of the symbols.