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Pitch Shifting and Dynamic Filtering. Rossum (1992a) Digital sampling instrument for digital audio data; Rossum (1992b) Dynamic digital IIR audio filter and method which provides dynamic digital filtering for audio signals. Digital sampling instrument for digital audio data.
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Pitch ShiftingandDynamic Filtering Rossum (1992a) Digital sampling instrument for digital audio data; Rossum (1992b) Dynamic digital IIR audio filter and method which provides dynamic digital filtering for audio signals
Digital sampling instrument for digital audio data • Multi-channel interpolative playback of digital audio data stored in a waveform memory provides improved interpolation of musical sounds by using seven or eight surrounding points. • Allowed a high channel count, enhanced access to waveform memory to allow improved • performance parity between computational units and memory. Also, the present • invention includes techniques which dramatically reduce the amount of memory • required to store the musical waveforms while still maintaining adequate • bandwidth and fidelity in the output.
The traditional approach to implement a sinc function interpolation has been to store the above coefficients in a table in memory. • The present invention uses a similar approach as sinc function, but stores the function in memory as a seventh or eighth order impulse response of a filter having deep (>90 dB down) notches at integral multiples of the sample rate and peaks only 60 dB to 70 dB down at half-integral multiples of the sample rate.