| 摘要 |
PURPOSE:To measure the AFT sensitivity of an AFC circuit IC with a simple measuring device by inputting frequencies proportionate to the lapsed time repeatedly to an AFC circuit IC, measuring the lapsed time corresponding to the output voltage of the said IC, and converting the measured time to a frequency. CONSTITUTION:A sweep signal oscillator 20 outputs the frequency proportionate to the lapsed time to the frequerncy input terminal of the AFC circuit IC 1 in terms of analog and repeatedly within a prescribed range. The output voltage of the IC 1 is measured by a time measuring means 40, the number of clock pulse from an oscillator 42 is counted by a counter 43, the prescribed output voltage range is decided on by a comparator 41, and the number of clock pulse form the counter 43 corresponding to a voltage variation within the said range i.e. the lapsed time is measured. A CPU 50 converts the lapsed time measurred by the means 40 to a frequency with the frequency proportionate to the lapsed time supplied form the oscillator 20 to obtain the AFT sensitivity of the IC 1, compares the obtained value with a set value to discriminate between a good article and a no-good article.
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