| 摘要 |
PURPOSE:To supply an accurate timer signal by adding or deleting a timer signal when the vaue of a counter which counts the timer signal coincides with the output of a switch stored with a previously calculated correction value. CONSTITUTION:An oscillating circuit 1 supplies a clock signal 4 to a CPU3 and a frequency dividing circuit 2. The circuit 2 processes the signal 4 by frequency division to output a timer signal 5. When the period of the signal 5 is, for example, 0.998ms for the 1,000Hz ideal frequency of the signal 5, a correction value 500 is set previously in a switch 8. When a counter 7 counts the signal 5 up to 500, a comparing circuit 9 outputs a strobe signal 10 for coincidence to switch a changeover switch 11 to a gate 12, and while the signal 5 is thinned out before being counted up to 500 and supplied to the CPU13, the counter 7 is reset. When the period of the signal 5 is, for example, 1.002ms, on the other hand, the switch 11 is changed over to the side of a one-shot circuit 13 before the signal 5 is counted up to 500 and one pulse obtained differentiating the leading edge of the output of a circuit 13 through a differentiating circuit 14 is added to supply the resulting signal to the CPU13. |
