Non linear filter with group delay at pre-response frequency for high res radio
US11996816B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 28, 2020 |
| Grant date | May 28, 2024 |
| Priority date | — |
| Expiry date | Nov 20, 2042 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H2017/0472
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Methods and devices are described for reducing the audible effect of pre-responses in an audio signal. The pre-responses are effectively delayed by employing a digital non-minimum-phase filter, which includes a zero lying outside the unit circle in its z-transform response. This zero is not paired with another zero at a reciprocal position inside the unit circle, as this would linearise the phase modification. The filtering can introduce a greater group delay at the pre-response frequency than at a low frequency, such as 500 Hz or even 0 Hz. The technique can be used to reduce pre-responses in an existing audio signal and also to pre-empt pre-responses that would be introduced to the audio signal by subsequent processing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.