Counting device, physical quantity sensor, counting method and physical quantity measuring method

A counting device which counts the number of signals having a linear relationship with a specific physical quantity, wherein the signals have substantially a single frequency if the specific physical quantity is constant, the device comprising:

• a signal cycle measurement unit configured to measure cycles of input signals during given counting periods whenever a signal is input;
• a frequency distribution generator configured to generate a frequency distribution of the cycles of the input signals during the given counting periods, based on a measurement result from the signal cycle measurement unit;
• a representative value calculator configured to calculate a representative value of a distribution of the cycles of the input signals, based on the frequency distribution;
• a signal combination unit configured to combine a first cycle that is less than 0.5 times the representative value with a cycle measured immediately after the first cycle so as to set the combined cycle as a new cycle of a signal waveform, wherein when the combined cycle is less than 0.5 times the representative value, the signal combination unit continues to perform the combination process until newly-combined cycle is equal to or greater than 0.5 times the representative value;
• a signal counter configured to count the number of the cycles of the input signals during the given counting period, wherein the number of the cycles contains the new half cycles combined by the signal combination unit;
• and
• a correction value calculator configured to calculate, based on the measurement result from the signal cycle measurement unit, a total number Ns and a total number Nwn so as to correct the number of the cycles of the input signals counted by the signal counter, based on the total number Ns and the total number Nwn, wherein Ns represents the total of the number of the half cycles that are less than 0.5 times the represent value, and Nwn represents the total of the number of the half cycles that are equal to or greater than (n+0.5) and less than (n+1.5) times the representative value, where n is a natural number of 1 or more.

A method of counting the number of signals having a linear relationship with a specific physical quantity, wherein the signals have substantially a single frequency if the specific physical quantity is constant, the method comprising:

• (a) counting the number of half cycles of an input signal during given counting periods;
• (b) measuring the half cycles of the input signals during the given counting periods whenever a half cycle of the signal is input;
• (c) generating a frequency distribution of the half cycles of the input signals during the given counting periods, based on a measurement result in the step (b);
• (d) calculating a representative value of a distribution of the half cycles of the input signals, based on the frequency distribution;
• and
• (e) calculating, based on the measurement result in step (b), a total number Ns and a total number Nwn so as to correct the number of the half cycles of the input signals in step (a), wherein Ns represents the total of the number of the half cycles that are less than 0.5 times the represent value, and Nwn represents the total of the number of the half cycles that are equal to or greater than 2n and less than (2n+2) times the representative value, where n is a natural number of 1 or more.

A method of counting the number of signals having a linear relationship with a specific physical quantity, wherein the signals have substantially a single frequency if the specific physical quantity is constant, the method comprising:

• (a) measuring cycles of input signals during given counting periods whenever a signal is input;
• (b) generating a frequency distribution of the cycles of the input signals during the given counting periods, based on a measurement result in step (a);
• (c) calculating a representative value of a distribution of the cycles of the input signals, based on the frequency distribution;
• (d) combining a first cycle that is less than 0.5 times the representative value with a cycle measured immediately after the first cycle so as to set the combined cycle as a new cycle of a signal waveform, wherein when the combined cycle is less than 0.5 times the representative value, wherein step (d) comprises:
• continuing to perform the combination process until newly-combined cycle is equal to or greater than 0.5 times the representative value;
• (e) counting the number of the cycles of the input signals during the given counting period, wherein the number of the cycles contains the new half cycles combined in step (d);
• and
• (f) calculating, based on the measurement result in step (a), a total number Ns and a total number Nwn so as to correct the number of the cycles of the input signals counted in step (e), wherein Ns represents the total of the number of the half cycles that are less than 0.5 times the represent value, and Nwn represents the total of the number of the half cycles that are equal to or greater than (n+0.5) and less than (n+1.5) times the representative value, where n is a natural number of 1 or more.