Abstract: The vibration level (a) is measured and applied to controllable filter (F). The filter (F) is a band pass filter that only passes a narrow band around a certain frequency that is determined by the frequency (1) of the machining cycle. The output signal of the filter is then compared to one or several reference levels (7) and an alarm signal is outputted in case of unacceptable deviation from the reference level.

Abstract: The present invention relates to means for reducing the gun firing dispersion in a weapon system. The gun (4) comprises a gun servo for aiming the gun at a target. A programmable signal generator (5) is arranged to produce a damping signal (z) which is supplied to the gun servo system at the firing of the gun and which signal has such a character that the oscillating movements which are generated at the firing of the gun are counteracted. A recoil sensor (6) is provided for sensing the start of the recoil movements of the gun and emitting a trigging pulse to the signal generator (5) which in turn is producing said damping signal (z) preferably in the form of a pulse train in which the number of pulses, the pulse widths, polarities and amplitudes of individual pulses can be varied and which has a certain time relationship with the gun firing moment.