The sampling rate is important to the success of a filtering operation. The maximum frequency component of the signal of interest usually determines the sampling rate. In general, choose a sampling rate 10 times higher than the highest frequency component of the signal of interest.
Make exceptions to the previous sampling rate guideline when filter cut-off frequencies must be very close to either DC or the Nyquist frequency. Filters with cut-off frequencies close to DC or the Nyquist frequency might have a slow rate of convergence. You can take the following actions to overcome the slow convergence:
In general, adjust the sampling rate only if you encounter problems.