Headphone receiver apparatus for use with low power transmitters
US7532718B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 2005 |
| Grant date | May 12, 2009 |
| Priority date | — |
| Expiry date | Dec 23, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2420/07
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A headphone receiver apparatus for use with low power transmitters includes a pair of headphone speaker enclosures connected by a headband. An antenna element in the form of a spring steel band or a plastic cable/antenna band where one of the conductors is utilized as the antenna is configured generally concentric with but offset from the headband and the user's head by at least 0.5 inches over at least some length of the antenna. Low-noise performance is improved by a low noise amplifier incorporated before the receiver IC, and a bandpass filter interposed between the low noise amplifier and the receiver IC. A base-loading inductor is used to tune the antenna element to resonance, with or without capacative end-loading. Lumped inductors, ferrite beads, or a parallel resonant LC circuit may be used to isolate the shield conductor at RF frequencies, and/or to reduce the loading of the other conductors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.