System and method for an image rejecting single conversion tuner with phase error correction
US6714776B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 28, 1999 |
| Grant date | Mar 30, 2004 |
| Priority date | — |
| Expiry date | Sep 28, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D7/18
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A system and method for a single conversion tuner which generally uses phase shifted in-phase and quadrature-phase signal paths as an image rejection circuit. Through the use of broadband input LNA and mixer circuits, substantially the entire input signal bandwidth may be processed in the tuner. The broadband input LNA may pass the signal through to the mixers, which may split the signal into in-phase and quadrature terms. Then the in-phase term may be shifted by plus 45 degrees and the quadrature may be shifted by minus 45 degrees. When the terms are subsequently summed together, the desired signal components add together, while the undesired image components subtract from each other. In this way the image signal is suppressed, thus generally eliminating the need for a notch filter. A phase error correction feedback loop may be implemented to compensate for errors between the separate circuit paths. The feedback loop may use a test signal to monitor the phase error between the in-phase and quadrature circuit paths, and may correct for the phase error by shifting the phase of the LO signal sent to one or both of the broadband mixers. The feedback loop thus generally corrects for an…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.