A device for differentiating signals of very low speed
T Murata · Journal of Physics E Scientific Instruments · 1975
In order to calculate creep rate automatically, a new differentiator using a pulse motor has been developed. The angle of rotation of the pulse motor is controlled so that the angle of revolution is proportional to the input voltage. Accordingly, the number of pulses, n, which are fed into the motor is proportional to the input voltage, E. As the differential value of E with respect to time is proportional to n per unit time, the analogue value can be obtained by the integration of the pulses having a constant height and width during a constant time. The device can differentiate signals having a rate between 5*10 -3 -5*10 -1 V min -1 with a precision of +or-1.5% of the full scale reading.