Apparatus for generating an instantaneous value signal of a number of revolutions

摘要

The signal generator generates an analogue signal representing the instantaneous value of the rotational speed of the motor. The signal is derived from a digital or essentially digital signal whose frequency is proportional to the number of rotations (N) to be detected. The generator includes a device (24) incorporating an integrating component (39). This receives the signal and converts it into a synchronised signal with sloping edges. This signal is fed to an input of a component (50) which derives a difference between two signals. The other input of this component receives a signal which includes, at least approx., only the alternating voltage part of the signal with sloping edges. This provides an analogue rotational speed actual value signal at the output (25) of the subtracting component (50). The analogue signal is essentially in the form of a constant voltage dependent on the number of rotations (N). The subtracting component (5) is preferably an operational amplifier.