The formula mentioned in docs for [First order low pass filter](https://kmilo17pet.github.io/qlibs/qssmoother_desc.html#qssmoother_lpf1) have a typo: ### $y(t)=x(t)+\alpha[y(t-1)+x(t)]$ it should have **minus**: ### $y(t)=x(t)+\alpha[y(t-1)-x(t)]$