A computer-implemented method for filtering a signal representing a physical process, the method comprising: passing a first signal through two or more integration paths, each path including a sequence of two or more integration stage blocks; and calculating at least one final output signal based on an arithmetical combination of outputs of the two or more integration paths, wherein each of the first signal and the at least one final output signal comprises a sequence of samples, each sample representing a value of the first signal or the at least one final output signal at a sampling time, wherein each integration stage block in the sequence of integration stage blocks: receives an input signal comprising a sequence of input samples and generates an output signal comprising a sequence of output samples; comprises a data window having an associated length in samples, the data window covering a sequence of most recent input samples received by the integration stage block, only the sequence of the most recent input samples influencing a corresponding output sample in the sequence of output samples generated by the integration stage block; multiplies a newly received input sample by a coefficient to generate a corresponding product value, the product value remaining unchanged while the data window covers the input sample; and calculates, at or after the sampling time, the corresponding output sample through a numerical integration over product values corresponding to the most recent input samples covered by the data window, wherein each of the two or more integration stage blocks comprises a same data window length, and wherein the output signal of a preceding block in the sequence of integration stage blocks forms the input signal to a next block in the sequence of integration stage blocks. passing a first signal through two or more integration paths, each path including a sequence of two or more integration stage blocks; and calculating at least one final output signal based on an arithmetical combination of outputs of the two or more integration paths, wherein each of the first signal and the at least one final output signal comprises a sequence of samples, each sample representing a value of the first signal or the at least one final output signal at a sampling time, wherein each integration stage block in the sequence of integration stage blocks: receives an input signal comprising a sequence of input samples and generates an output signal comprising a sequence of output samples; comprises a data window having an associated length in samples, the data window covering a sequence of most recent input samples received by the integration stage block, only the sequence of the most recent input samples influencing a corresponding output sample in the sequence of output samples generated by the integration stage block; multiplies a newly received input sample by a coefficient to generate a corresponding product value, the product value remaining unchanged while the data window covers the input sample; and calculates, at or after the sampling time, the corresponding output sample through a numerical integration over product values corresponding to the most recent input samples covered by the data window, wherein each of the two or more integration stage blocks comprises a same data window length, and wherein the output signal of a preceding block in the sequence of integration stage blocks forms the input signal to a next block in the sequence of integration stage blocks. receives an input signal comprising a sequence of input samples and generates an output signal comprising a sequence of output samples; comprises a data window having an associated length in samples, the data window covering a sequence of most recent input samples received by the integration stage block, only the sequence of the most recent input samples influencing a corresponding output sample in the sequence of output samples generated by the integration stage block; multiplies a newly received input sample by a coefficient to generate a corresponding product value, the product value remaining unchanged while the data window covers the input sample; and calculates, at or after the sampling time, the corresponding output sample through a numerical integration over product values corresponding to the most recent input samples covered by the data window, wherein each of the two or more integration stage blocks comprises a same data window length, and wherein the output signal of a preceding block in the sequence of integration stage blocks forms the input signal to a next block in the sequence of integration stage blocks.