| 摘要 |
PURPOSE:To perform an easy and reliable selection of a signal, by a method wherein, through application of a rise and a fall edge of a signal and edge by means of a retrigable monostable multivibrator as a clock, a specified signal in a repeating pattern is fetched via shift register etc. CONSTITUTION:A pulse and a period, corresponding to a rise and a fall edge of a signal from a differentiation circuit 1, and a pulse, corresponding to an edge, formed by a monostable multivibrator 2 and being set to a reference of each pattern by a retrigable monostable multivibrator 2 and a differentiation circuit 3 set between a longest period and a second period therto, are applied as a clock to a shift register 5 through an OR circuit 4. A code output, corresponding to each signal contained in each pattern, of a repeat pattern from the regeister 5, is decoded by a decoder 6. This causes a given signal, included in each pattern, of a repeat pattern to be easily and accurately selected by an FF 7 operating in conformity with the decoder 6, and permits the rapid and reliable measurement of a period and frequency of a signal without the use of an oscillator and the like. |
