Variable frequency switching amplifier and method therefor
US6819912B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 5, 2001 |
| Grant date | Nov 16, 2004 |
| Priority date | — |
| Expiry date | Mar 27, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B15/04
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A switching amplifier generates noise at its switching frequency and harmonics thereof. The noise at these harmonics, for an audio amplifier, will be generated with significant amplitude in the AM band. Thus, an AM tuner will experience interference problems if the tuner frequency is sufficiently close to one of these harmonics. To avoid this problem the switching frequency of the switching amplifier is chosen based on the tuner frequency. Thus, the switching frequency is chosen to avoid having harmonics at or too near the chosen tuner frequency. The switching amplifier is disabled when the tuner is in seek or scan mode. Instead of using the tuner frequency to determine what switching frequency should be used to avoid interference, the interference can be detected directly to cause a change in the switching frequency and thus remove the interference.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.