| 摘要 |
PURPOSE:To obtain an inexpensive rotational speed meter with a simple constitution, by counting the rotational cycle by using clock pulses, and obtaining said inverse number through a priority encoder, a rate multiplier and a down counter. CONSTITUTION:The rotation sensor 10 generase a signal having a frequency proportional to the rotational speed of a rotating body. Said signal is applied to the reset terminal of a counter 14 through a delay circuit 12. Said counter 14 counts the cycle of the rotational signal by means of clock pulses and outputs the count value to a priority encoder 15. The encoder 15 outputs a signal according to the position of the leading bit of the binary output of the counter 14 to control a rate multiplier 16 so that when the count value of the counter 14 is small, the down pulse frequency to be outputted to a down counter 17 is made large, while count value is large, the frequency is made small. Thereby, the down counter value is made approximately inversely proportional to the count value, corresponding to the rotational speed. |
