| 摘要 |
PROBLEM TO BE SOLVED: To reduce the measuring time of an oscillation frequency and to quickly adjust the oscillation frequency of a crystal oscillator to a target frequency by performing LED display of the results of the number of counts as frequency deviation and adjusting the capacitance of a capacitor so that the display results can be the frequency deviation being a target. SOLUTION: A measurement start and end pulse generating part 106 generates a start pulse 115 at the rise of a frequency synchronized by a synchronizing part 105 and generates an end pulse 116 at the fall. A latching part 110 fetches the number of counts of a counting part 109 when the end pulse 116 is generated and sends the number of counts to a decoding part 111. The part 111 converts the number of counts into data for being displayed on an accuracy displaying part 112. Then, LED display is performed in 17 stages in accordance with the frequency deviation of a crystal oscillator 101 to be adjusted, and when the LED display exceeds the regulated range between -4 and +4, the readjustment of an oscillation frequency is performed by changing and adjusting the capacity and of a capacitor 115.
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