| 摘要 |
The measuring system of the disclosure has two oscillators of different frequencies. The oscillations of the high frequency oscillator are counted for a time corresponding to a portion, for example one-eighth, of the period of the low frequency oscillator. If the count is less or greater than a selected count, for example 4,096, the frequency of the low frequency oscillator is corrected by approximately one high frequency period in the one-eighth low frequency period. By this method the oscillators are brought into near-synchronism, so that there are counted exactly 4,096 high frequency oscillations during the one-eighth period of the low frequency oscillator, but neither 4,097 or more, nor 4,095 or less. The correction is accomplished by excluding or including one at a time, various resistors in the frequency determining portion of the low-frequency circuit by the use of transmission gates in parallel with the resistors. The system may be used to measure, for example, weight. The capacity in the frequency determining portion of the high frequency oscillator is increased as a function of the weight. The frequency of the high frequency oscillator is thereby reduced. Suitable circuits respond to count the changed oscillations relative to the unchanged calibration period of the low frequency oscillator to derive a measure of the weight.
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