| 摘要 |
PURPOSE:To increase the measuring accuracy over the entire measuring range, by securing the automatic switching between the two pulse generators having different generating coefficients after detecting their revolving speeds. CONSTITUTION:The output voltage of comparator 6 is turned to the zero voltage from the constant voltage if the pulse duration is long enough for the time during which the output voltage of low-speed range measuring pulse generator 2 is at a certain level. When the time elapses and the output voltage of generator 2 lowers down to the zero voltage with the output voltage of comparator 6 kept at the zero level, the output of flip-flop FF8 selects high-speed range measuring pulse generator 1. In case the pulse duration of generator 2 is short, the output voltage of comparator 6 is kept at a certain level. And the output of FF8 selects generator 2. Here the voltage of the external control input terminal is changed to the zero level from a certain level, and thus the control input of FF8 is locked with the output kept as it is. Accordingly, the measuring accuracy can be increased over the entire measuring range. |
