Automute detection in digital audio amplifiers
US7797065B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 2, 2005 |
| Grant date | Sep 14, 2010 |
| Priority date | — |
| Expiry date | Jul 2, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2200/351
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A digital audio processor for a digital audio receiver having an improved automute sequence is disclosed. The digital audio processor includes automute detection circuitry that monitors the amplitude of digital audio signals before and after the application of digital filters by digital audio processing circuitry. The amplitude of the input signals are compared against a first threshold level, while the amplitude of the output signals are compared against a second threshold level. In response to the amplitude of the input signals for all of the audio channels falling below the first threshold for a selected time period, a gain stage in each channel ramps down the volume to a mute level, and pulse-width-modulation circuitry is disabled. If the output signal amplitude falls below a second threshold for a channel, the pulse-width-modulation circuitry for that channel is disabled. Hysteresis for the input signal amplitude is preferably added into the automute exit determination.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.