| 摘要 |
PURPOSE:To select optionally a frequency for calibrating the delay circuit by inputting the same signal of calibration frequency to the delay circuit to be calibrated and a reference delay means, and comparing the phases of the delay circuit to be calibrated and reference delay means with each other and finding the calibration value for the delay circuit to be delayed. CONSTITUTION:The same signal is distributed and inputted to the delay circuit 102 to be calibrated and reference variable delay circuit 103 and the phase difference between both their outputs is measured by a phase comparator 104. At this time, the set value of the reference variable delay circuit 103 is varied in order to search for setting data of the circuit 102 to be calibrated with which the phase difference is invariably constant, thereby obtaining the setting data corresponding to the set delay time of the delay circuit 102 to be calibrated as the calibration value. Consequently, the calibration value for the circuit 102 to be calibrated is found fast at the optional frequency with high accuracy. |
