Multiple input frequency locked loop
US5943381A · kind A · utility
27Cited by
5References
17Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | May 2, 1997 |
| Grant date | Aug 24, 1999 |
| Priority date | — |
| Expiry date | May 2, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/087
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A dual locked loop is disclosed comparing preferably a GPS signal with an E1 signal and the E1 signal with the output of the loop. The GPS signal is low pass filtered to provide a low pass filtered GPS versus E1 signal that is used as a calibration for a closed loop having a second low pass filter for filtering the comparisons of the E1 and the output signal. By appropriately selecting the filter parameters, the output stability can track the stability of the local oscillator driving the NCO for short term stability, the medium term stability of the E1 signal and the long term stability of the GPS signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.