摘要 |
The frequency of a pulse generator, which could be the tachometer of a motor, is measured with a fast clock and a slow clock using a computer to calculate the frequency omega =k N1/N2, where N2 is a count of pulses accumulated in a register during each period of the slow clock while N1 is the count of the fast clock during the same period. Depending upon whether the measured frequency is higher or lower than the slow clock frequency, a comparator causes measurement to occur at the end of N2 pulses or with N2=1. |