| 摘要 |
In a frequency discrimination circuit, a first retriggerable monostable multivibrator is triggered in response to the period of a signal to be measured to produce a first pulse output having a pulse width corresponding to the period of a reference frequency, and a second retriggerable monostable multivibrator produces a second pulse output having a pulse width wider than that of the first pulse output in response to a repetitive pulse signal which has a constant period smaller than the pulse width of the first pulse output and is generated only when the first pulse output is not produced, whereby it is possible to discriminate whether or not the frequency of the signal to be measured is higher than the reference frequency with high response characteristics.
|
