Patent ID: 7684957
Filing Date: 2010-03-23
Classification: G01S

Abstract:
1. A counting device comprising: counting means for counting the number of signals input during a counting interval, the number of signals having a linear relationship with a physical quantity, and the signals having a substantially single frequency when the physical quantity is constant; period measurement means for measuring a period of a signal every time a signal is input during the counting interval; frequency distribution generating means for generating a frequency distribution of signal periods during the counting interval from a measurement result obtained by said period measurement means; representative value calculation means for calculating a representative value of a distribution of periods of signals from the frequency distribution generated by said frequency distribution generating means; and correction value calculation means for obtaining a total sum Ns of frequencies in a class not more than a first predetermined multiple of the representative value calculated by said representative value calculation means and a total sum Nw of frequencies in a class not less than a second predetermined multiple of the representative value from the frequency distribution generated by said frequency distribution generating means, and correcting a count result obtained by said counting means on the basis of the frequencies Ns and Nw.