Phase lock loop with tracking filter for attenuating spurious signals of a swept local oscillator
US9083351B1 · kind B1 · utility
8Cited by
8References
16Claims
0Family size
Assignee
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Key dates
| Filing date | Mar 11, 2013 |
| Grant date | Jul 14, 2015 |
| Priority date | — |
| Expiry date | Jul 4, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/093
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A high spectral purity swept local oscillator including a tracking filter. The output of a swept DDS oscillator may be improved by filtering it with a band-pass filter having an adjustable center frequency, which is adjusted in real time to track the instantaneous frequency of the DDS oscillator. The tracking may be accomplished by comparing, using a phase comparator, the phase at the output of the band-pass filter to the phase at its input, and feeding back to the frequency control input of the band-pass filter a signal corresponding to the phase difference measured by the phase comparator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.