| 摘要 |
To measure frequency or period of an unknown pulse train (I1), its pulses (n1, n2, ...nx) are counted during a gate time (TG). Between in each case two pulses (n0-n1, n1-n2, ...nx-nx+1) of the unknown pulse train (I1), the pulses of another pulse train (I3), the frequency (f3) of which is much higher than the frequency (f1) of the unknown pulse train (I1), are counted. If the beginning of the gate time (TG) is detected during one such counting period (n0-n1), the counts at the beginning (Z0) and end (Z2) of this counting period and at the beginning (Z1) of the gate time (TG) are stored. As well, the counts (Z3, Z4, Z5) of the counting period (nx-nx+1) at the end of the gate time (TG) are stored. From the number of pulses (x), the gate time (TG) and the counts (Z1...Z5), the unknown frequency (f1) is determined in accordance with the equation. (TG . f1 = x + (Z2-Z1)/Z2-Z0-(Z5-Z4)/Z5-Z 3) <IMAGE>
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