| 摘要 |
PROBLEM TO BE SOLVED: To provide a counter which can correct a counting error with computational complexity smaller than usual, and a method for counting and a physical quantity sensor which can correct the counting error of MHP (mode hop pulse) with the computational complexity smaller than usual and thus can improve the measuring accuracy of the physical quantity and a method for measuring a physical quantity. SOLUTION: An oscillation frequency measuring device has a laser driver 4 which makes a semiconductor laser 1 oscillate, the counter 7 which counts an interference waveform contained in an output of a photodiode 2 which converts an output of the semiconductor laser 1 into an electric signal, and an arithmetic device 8 which determines the physical quantity of an object 10 from the result of counting of the counter 7. The counter 7 measures the period of the interference waveform in a prescribed counting term, calculates the average value of the period of the interference waveform as a representative value from the result of the measurement and counts one measured period as one signal, and performs addition of n to the result of counting when the measured period is a multiple of (n+0.5) or more of the representative value to less than a multiple of (n+1.5) thereof, as to the all results of measurement of the periods during the counting period. COPYRIGHT: (C)2011,JPO&INPIT |
