DIGITAL ENCAPSULATION OF AUDIO SIGNALS

摘要

Encoding and decoding systems are described for the provision of high quality digital representations of audio signals with particular attention to the correct perceptual rendering of fast transients at modest sample rates. This is achieved by optimising downsampling and upsampling filters to minimise the length of the impulse response while adequately attenuating alias products that have been found perceptually harmful.

主权项

1. A system comprising an encoder and a decoder for conveying the sound of an audio capture, wherein the encoder is adapted to furnish a digital audio signal at a transmission sample rate from a signal representing the audio capture, and the decoder is adapted to receive the digital audio signal and furnish a reconstructed signal,
wherein the encoder comprises a downsampler adapted to receive the signal representing the audio capture at a first sample rate which is a multiple of the transmission sample rate and to downsample the signal to furnish the digital audio signal; and, wherein an impulse response of the encoder and decoder in combination is characterised by a duration for its cumulative absolute response to rise from 1% to 95% of its final value not exceeding five sample periods at the transmission sample rate, wherein the cumulative absolute response is a time integration of the absolute magnitude of the impulse response.