| 摘要 |
PURPOSE:To detect the value of a changing number of rotation by controlling the counting and the reading of a counter which divides the frequency of detection pulses which is proportional to the number of rotation to count clocks. CONSTITUTION:A pulse signal (a) having a frequency proportional to the number of rotation due to a contactless switch 3 has the frequency divided by a frequency divider 11 to become a frequency-divided clock (c), and a NAND gate 12 to which count clocks are impressed is controlled. Meanwhile, the fall of the clock (c) is detected by a pulse generator 14, and the detection signal resets an 8-bit counter 13, which counts count clocks passing through the gate 12, and an overflow register 15. By this operation, the counter 13 counts count clocks while the clock (c) is in the high level; and contents of the counter 13 and the register 15 are read out to detect surely the value of the changing number of rotation while the clock (c) is in the low level. |
