| 摘要 |
PURPOSE:To detecting a rotating speed with high precision and to repeating the detection at specific intervals over the entire range including the zero speed, by counting pulses generate within a specific time of a pulse signal of frequency proportional to the rotating speed to be detected. CONSTITUTION:An analog signal 29 is led to an A/D converter 5. A pulse signal 30 is led as count input pulses to a pulse counter 9 and also led as a clear signal to pulse counter 10. Internal reference pulses 31 in a CPU14 are counted repeatedly up to a specific number PT to generate the 1st timing pulse 32 with a period of specific time T and the 2nd timing pulse 33 lagging it slightly. The 1st timing pulse 32 is supplied to the A/D converter 5 as an A/D conversion command signal and to latch circuits 12 and 13 as a latch command signal. The 2nd timing pulse 33 is used as the clear signal of the pulse counter 9. Thus, a speed detection value is obtained repeatedly invariably at a specific period over the entire speed range including the zero speed. |
