The signals generated by the acceleration- and the force-probe are first filtered by a
low-pass-filter (8th order Butterworth-filter with a cut-off frequency of either 800 hertz or 3 kilohertz) to suppress measurement noise and eliminate aliasing and then are passed on to the measurement card (NI PCI 6052E, http://www.ni.com/) implemented in the PC along with the strain measurements. These signals, which are
proportional to strain, require no filtering but a differential amplification to be capable of eliminating interference which can easily occur using such high resistance sensor types.