| 摘要 |
PURPOSE:To take out a pulse signal having a prescribed frequency range by connecting an F/V converter which converts the frequency of the pulse signal to a voltage, a comparator, and a gate in such relations that the gate is opened for a prescribed frequency range to permit the pulse signal to pass through the gate. CONSTITUTION:This circuit is provided with a buffer amplifier 1, and the input side of this buffer amplifier 1 is connected to an input terminal connected to a pulser which generates the pulse signal. The detection output of a rotation detecting element such as the pulser or the like which detects the rotation number of an engine is supplied to an F/V converter 2 through the buffer amplifier 1. This converter 2 generates an output voltage corresponding to the inputted frequency as shown in a figure 3. Since a reference voltage V1 is given to a reference input terminal of the second comparator 4, a voltage shown in a figure 5 is generated in the output side of the comparator 4. Since the output of the comparator 4 is inverted by an inverter 5 and is supplied to a gate 6, the gate 6 generates an output only when the frequency of the pulse signal obtained by the pulser is between f1 and f2.
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