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

Abstract

The counting device includes: a signal counter that counts the number of half cycles of input signals during given counting periods; a signal half cycle measurement unit that measures the half cycles; a frequency distribution generator that generates a frequency distribution of the half cycles; a representative value calculator configured to calculate a representative value of a distribution of the half cycles; a correction value calculator configured to calculate a total number Ns and a total number Nw n so as to correct the number of the half cycles, wherein Ns represents the total of the number of the half cycles that are less than 0.5 times the represent value, and Nw n 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.

1 - 6 . (canceled) 
     
     
         7 . 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 Nw n  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 Nw n , wherein Ns represents the total of the number of the half cycles that are less than 0.5 times the represent value, and Nw n  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.   
     
     
         8 . The device according to  claim 7 ,
 wherein the correction value calculator is configured to calculate the corrected number N′ of the cycles of the input signals, based on the following expression:   
       
         
           
             
               
                 N 
                 ′ 
               
               = 
               
                 N 
                 - 
                 Ns 
                 + 
                 
                   
                     ∑ 
                     
                       n 
                       = 
                       1 
                     
                     
                       n 
                       max 
                     
                   
                    
                   
                     ( 
                     
                       n 
                       × 
                       
                         Nw 
                         n 
                       
                     
                     ) 
                   
                 
               
             
           
         
         
           
             
               
                 n 
                 max 
               
               ≦ 
               
                 
                   T 
                   max 
                 
                 
                   T 
                    
                   
                       
                   
                    
                   0 
                 
               
             
           
         
         wherein the number of the cycles of the input signals counted by the signal counter is N, the representative value is T 0  and the maximum value of the cycles of the input signals is T max . 
       
     
     
         9 . The counting device according to  claim 7 ,
 wherein the representative value is one of the median, the mode, the mean and a class value, the class value having a maximum value obtained by multiplying the class value by a frequency corresponding to the class value.   
     
     
         10 - 16 . (canceled) 
     
     
         17 . 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 Nw n  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 Nw n  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.   
     
     
         18 . The counting method according to  claim 17 ,
 wherein step (f) comprises: calculating the corrected number N′ of the half cycles of the input signal, based on the following expression:   
       
         
           
             
               
                 N 
                 ′ 
               
               = 
               
                 N 
                 - 
                 Ns 
                 + 
                 
                   
                     ∑ 
                     
                       n 
                       = 
                       1 
                     
                     
                       n 
                       max 
                     
                   
                    
                   
                     ( 
                     
                       n 
                       × 
                       
                         Nw 
                         n 
                       
                     
                     ) 
                   
                 
               
             
           
         
         
           
             
               
                 n 
                 max 
               
               ≦ 
               
                 
                   T 
                   max 
                 
                 
                   T 
                    
                   
                       
                   
                    
                   0 
                 
               
             
           
         
         wherein the number of the cycles of the input signals counted in step (e) is N, the representative value is TO and the maximum value of the cycles of the input signals is T max . 
       
     
     
         19 . The counting method according to  claim 17 ,
 wherein the representative value is one of the median, the mode, the mean and a class value, the class value having a maximum value obtained by multiplying the class value by a frequency corresponding to the class value.   
     
     
         20 . (canceled)