Craig, Most of the filtering is done in DSP. The 'roofing filters' add some protection by restricting the bandpass seen by the ADC, but do not provide the final filtering. 73, Don W3FPR On 12/31/2013 11:09 AM, Craig Schroeder wrote: > A particular point made in regard to SDR on the KX3 was hardware filter options vs software filters. > >