Process for reducing the pre-echoes or post-echoes affecting audio recordings
US5717768A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 4, 1996 |
| Grant date | Feb 10, 1998 |
| Priority date | — |
| Expiry date | Oct 4, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/22
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
For various values of an integer p, short-term discrete Fourier transforms X(p,k) and X.sub..tau. (p,k) of the audio signal shifted by pR samples and of the audio signal shifted by pR+.tau. samples are respectively calculated, R denoting a predetermined integer and .tau. denoting a time shift between the echo and the portion of signal which gave rise to it, a corrected signal is calculated in the frequency domain by nonlinear transformation of X(p,k) taking account, for the various values of the frequency index k, of a value representative of an attenuation factor relating to the echo and of X.sub..tau. (p,k), and a short-term component of a corrected signal is calculated in the time domain by short-term inverse Fourier transform of the corrected signal in the frequency domain. The corrected signal in the time domain is then formed by weighted summation of its short-term components. Application to the digital reprocessing of analog recordings.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.