Patent ID: 8599996

Claim:
A counting device counting signals wherein there is a linear relationship between a specific physical quantity and the number of signals and wherein the signal has essentially a single frequency when the specific physical quantity is constant, comprising: a binarizing device binarizing an inputted signal; a signal counter counting a number of run lengths of the binarized signal outputted from the binarizing device during a prescribed counting interval; a run length measuring device measuring the run lengths of a binarized signal during the counting interval each time a run length worth of a signal is inputted; a frequency distribution generator generating a frequency distribution for the run lengths of the binarized signals during the counting interval, from the measurement results by the run length measuring device, for first run lengths, which are from a rising edge until the subsequent falling edge of the binarized signal, and second run lengths, which are from a falling edge to the subsequent rising edge of the binarized signal; a representative value calculator calculating a representative value T H for the distribution of the first run lengths from the first run length frequency distribution and calculating a representative value T L for the distribution of the second run lengths from the second run length frequency distribution; and a corrected value calculator calculating a total Ns H number of first run lengths wherein the length is no less than 0 times and less than 1 times the representative value T H , a total Ns L number of second run lengths wherein the length is no less than 0 times and less than 1 times the representative value T L , a total Nw nH number of first run lengths wherein the lengths are no less than {T H +n−0.5)×(T H +T L )} and less than {T H +n+0.5)×(T H +T L )}, and a total Nw nL number of second run lengths wherein the lengths are no less than {T L +n−0.5)×(T H +T L )} and less than {T L +n+0.5)×(T H +T L )}, and calculating a number of inputted signals by correcting the counting results by the signal counting means based on these frequencies Ns H , Ns L , and Nw nH , and Nw nL .