In a gantry for an x-ray computed tomography apparatus with a rotor and a
stator and a device for measurement of the rotation angle as well as a
method for measurement of the rotation angle, a disc is provided with
markings that rotate relative to a detection device for detection of the
markings. Electrical signals are generated by the detection device, and
an evaluation device converts the signals into a measurement signal
corresponding to the respective rotation angle. To increase the precision
of the measurement, a low-pass filter is connected upstream of the
evaluation device.