A tissue stimulator including a sensing unit, wherein the sensing unit includes an A/D converter that samples an analog signal using a sampling clock and converts the analog signal into a digital signal. The tissue stimulator includes a digital filter with an input, wherein the input is connected to an output of the A/D converter. Using a filter clock, the digital filter filters the digital signal, and wherein the filter clock is a multiple of the sampling clock for a specific period of time T.
