| 摘要 |
PURPOSE:To enable fast detection regardless of changes in the pulse frequency even at any shorter detection cycle, by storing differences of counter values at each fixed cycle sequentially to determine the frequency from a relationship between an integrated value of differences and the period. CONSTITUTION:Input pulses P are counted with a counter 1 to be read into a computer 2 sequentially at a fixed cycle T0 and differences or increments yn between the present values and the previous values are determined to be stored into a memory. Then, the computer 2 performs an operation of taking out a difference data thus obtained only for a specified cycle T with a certain time as reference, shifting the reference point sequentially. At this point, since an added value of (n) data each corresponds to a counter value within the cycle T, the sum A of the added values is determined and fn=A.K/(nXT0) is computed to obtain the frequency fn.
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