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

Claim 2:
3. The SN ratio estimation circuit according to claim 1,
wherein the updating unit includes:
a histogram generation unit that generates a histogram indicating the appearance frequency for each symbol included in the tentative decision signal output by the tentative decision unit;
a decision unit that, on the basis of error between a histogram of the appearance frequency of each symbol in the reference signal and the histogram generated by the histogram generation unit, decides whether or not the degree of agreement between the appearance frequencies is within a predetermined permissible range, and when it is decided that the degree of agreement is within the permissible range, outputs the instruction signal to the SN ratio calculation unit; and
an update computation unit that updates the scale value or updates the threshold change rate so as to reduce the error when the decision unit decides that the degree of agreement is not within the permissible range.