I'm trying to oversample to smooth the display on my software audio scope using band limited (sinc) interpolation. I have a quick question to ask. Which of the following implementations is liable to take more processing time: 1) Padding my data, and then convolving the original (non-zero) samples with a sinc function (from a LUT). I think it's only feasible to have a LUT for a sinc of unity amplitude. or 2) Doing an FFT on my original sample set. Padding, and multiplying by a rectangular window, then doing an iFFT to return to the time domain. The FFT library I would use would be FFTW. Cheers Henry