Short synchronization time data modem
US6625209B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 29, 1999 |
| Grant date | Sep 23, 2003 |
| Priority date | — |
| Expiry date | Mar 29, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04W4/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A short synchronization time modem comprising a GPS receiver for receiving a broadcasted signal comprising a high precision clock. When a first short synchronization data modem communicates with a second, a PLL in each data modem synchronizes its own local clock to the same high precision clock derived from the same received broadcasted signal. The modems connect for the first time using one of many clock recovery schemes known to the modem designers. Once they disconnect, the modems keep their clocks synchronized using a local GPS receiver and the received broadcasted signal. This prevents the local clock of the modems from drifting, which significantly reduces the time period the modems need to synchronize the next time they connect.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.