Calibration method of time measurement apparatus
View Patent ↗There is provided a calibration method for a time measurement apparatus having a time-voltage converter for converting the time interval of measurement signals and clock signals to voltage, an analog-digital converter for converting this voltage to digital values, and a time interval measurement device for measuring this time interval from these digital values. The method includes a calibration signal generation step for calibrating the calibration signals for the subperiod of these clock signals, with these calibration signals having a shorter period difference than the time which corresponds to the resolution of this analog-digital converter; a frequency distribution analysis step for repeatedly measuring these calibration signals, finding this digital value, and analyzing the cumulative frequency distribution of these digital values; and a calibration determining step for determining the calibration value of these digital values such that this cumulative frequency distribution is linear.
1. A calibration method for a time measurement apparatus comprising a time-voltage converter for converting the time interval of measurement signals and clock signals to voltage, an analog-digital converter for converting said voltage to digital values, and a time-interval measurement unit for measuring said time interval of measurement signals from said digital values, said method comprising:
generating calibration signals for a subperiod of said clock signals by measuring the period of said clock signals, and shifting the period of said calibration signals by said period difference, with said calibration signals having a shorter period difference than the time corresponding to the resolution of said analog-digital converter;
measuring said calibration signals, finding said digital values, and analyzing the cumulative frequency distribution of said digital values;
determining a calibration value for said digital values such that said cumulative frequency distribution is linear;
converting said voltage converted by said time-voltage converter to said digital values in accordance with said calibration value; and
measuring said time interval of measurement signals from said digital values converted in accordance with said calibration value, wherein said time interval is outputted to a predetermined apparatus or stored in a memory of said time-interval measurement apparatus.
2. A calibration method for a time measurement apparatus comprising a time-voltage converter for converting the time interval of measurement signals and clock signals to voltage, an analog-digital converter for converting said voltage to digital values, and a time-interval measurement unit for measuring said time interval of measurement signals from said digital values, said method comprising:
generating calibration signals for a subperiod of said clock signals, with said calibration signals having a shorter period difference than the time corresponding to the resolution of said analog-digital converter;
measuring said calibration signals, finding said digital values, and analyzing the cumulative frequency distribution of said digital values, wherein the analyzing of said frequency distribution begins after the time interval of said calibration signals and clock signals becomes shorter than said time which corresponds to resolution;
determining a calibration value for said digital values such that said cumulative frequency distribution is linear;
converting said voltage converted by said time-voltage converter to said digital values in accordance with said calibration value; and
measuring said time interval of measurement signals from said digital values converted in accordance with said calibration value, wherein said time interval is outputted to a predetermined apparatus or stored in a memory of said time-interval measurement apparatus.