Low power transmitter frequency stabilization
US4794622A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 19, 1988 |
| Grant date | Dec 27, 1988 |
| Priority date | — |
| Expiry date | May 19, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2001/0491
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An improved miniature hand-held low power transmitter utilizing a surface acoustic wave (SAW) resonator as the control element to establish the carrier frequency of the oscillator. The SAW resonator stabilizes the frequency of the transmitter to within 0.05% of the center frequency of the SAW resonator for the condition of the user's hand enclosing the transmitter. This stability allows the companion receiver to operate at a narrow bandwidth, 0.1% of the center frequency of the SAW resonator, thus reducing the spurious noise received by the receiver. The configuration of the transmitter allows schemes such as pulse position or pulse width modulation to be utilized to encode the transmitted information. The physical size of the SAW resonator allows the transmitter to be mounted within a housing small enough to be enclosed by the user's hand.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.