Correction of Wow and Flutter Effects in Analog Tape Transfers

摘要

Here we describe a system whereby analog hardware is combined with the theory of nonuniform sampling in order to correct for wow and flutter effects in analog tape transfers. We show how in certain instances the medium itself can provide an accurate measurement of a recording's timing irregularities, in which case digital signal processing techniques permit a playback-rate correction of what is essentially an irregularly sampled audio waveform. Results using both real and synthetic data demonstrate the effectiveness of the method, both in cases of severe degradation as well as high-quality analog transfers heretofore considered normal.