Preventing false locks in a system that communicates with an implanted wireless sensor
US7492144B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 6, 2006 |
| Grant date | Feb 17, 2009 |
| Priority date | — |
| Expiry date | Mar 1, 2027 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B2560/0223
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
The present invention determines the resonant frequency of a wireless sensor by adjusting the phase and frequency of an energizing signal until the frequency of the energizing signal matches the resonant frequency of the sensor. The system energizes the sensor with a low duty cycle, gated burst of RF energy having a predetermined frequency. The system receives the ring down response of the sensor and determines the resonant frequency of the sensor, which is used to calculate a physical parameter. The system uses a pair of phase locked loops to adjust the phase and the frequency of the energizing signal. The system identifies false locks by detecting an unwanted beat frequency in the coupled signal, as well as determining whether the coupled signal exhibits pulsatile characteristics that correspond to a periodic physiological characteristic, such as blood pressure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.