Non-linear filter for oscillating sensor signal

摘要

The filter is supplied with a oscillating sensor signal at an input (E), and forms a difference (e) between the input signal and a filter output signal (A) in a substractor element (1). The produced difference is supplied once directly, and once over a non-linear transmission element (2) to an integrator. The non-linear transmission element is equipped with a medium range (M) with adjustable width (2a) at relatively small amplification. The width of the medium range is adjusted through an amplitude detector forming the difference between the largest and smallest amplitude value of the input signal during a period (T) of the disturbing oscillation in the input signal, in such way, that the time constant of the filter is reduced only slightly during changes of the usage signal, and that the disturbing oscillation signal does therefore not appear in the output signal of the filter.