| 摘要 |
PURPOSE:To digitize the frequency of a signal to be measured, by supplying a sampling clock to a counter through a gate circuit which is opened for the estimated period of the signal to be measured. CONSTITUTION:A signal S2 is supplied from a microcomputer M to a gate controlling circuit (a), which is then reset. A gate opening signal SG is generated at the 1st rise of the signal f1 to be measured to open the gate circuit (b), and the sampling clock f2 is supplied to the counter circuit C through the gate circuit (b). The counter circuit C starts counting the passed sampling clock f'2. The gate opening signal S2 is ceased the estimated period of the signal f1 later and the gate circuit (b) is closed. The counter circuit C is reset by a counter starting signal S2 and outputs counted values S4-Sn (or overflow signal S3) to the microcomputer M. |
