1. A circuit arrangement comprising a finite impulse response (FIR) digital filter comprising assigned filter coefficients storing filter coefficient weights, the circuit comprising: a data source configured to provide digital samples at discrete times; an external indicator generating an associated confidence value for each digital sample; wherein the FIR digital filter comprises an input receiving said digital samples, another input receiving said associated confidence values, and a filter output, and the FIR digital filter is configured to apply a digital filter function on said digital samples using said filter coefficients; wherein the FIR digital filter is further configured to modify or eliminate some of the filter coefficient weights depending on the confidence values associated to their corresponding digital samples and to determine a sum of the filter coefficient weights that have been removed or partially removed and to redistribute the sum of the removed filter coefficient weights onto the filter coefficients.