| 摘要 |
PURPOSE:To make the frequency of the signal to be measured measurable with high accuracy with simple circuit constitution by subtracting reference clock pulses from the prescribed preset value during the prescribed period of low frequency signals. CONSTITUTION:The frequency f to be measured entering from an input terminal 1 is divided by n by a gate signal generating circuit 2, to make gate signals. On the other hand, the output of a clock pulse generating circuit 10 built in with a quartz vibrator 9 is divided into (m) by a (m) frequency divider 11 and is inputted together with the gate signals to an AND gate circuit 4. The value prescribed times the reference value of the frequency to be measured is preset in a down counter 5 by a presetting circuit 6, so that the outputs of the gate circuit are down-counted. Upon ending of the counting, the output of the counter 5 is displayed in a display device 8 having a latch circuit. Thereby, the fluctuating components of the signal to be measured with respect to the reference value are measured accurately in real time. |
