Method and apparatus for detecting and compensating for undesired phase shift in a radio transceiver
US5894496A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 16, 1996 |
| Grant date | Apr 13, 1999 |
| Priority date | — |
| Expiry date | Sep 16, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2200/57
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The present invention provides a method and apparatus for detecting and compensating for transmitter phase shift in a radio transmitter. A local oscillator generates a local oscillator signal. A modulator such as an I/Q modulator modulates input signals onto the local oscillator signal to generate a forward signal. That forward signal is amplified and otherwise prepared for transmission via an antenna. The transmitted signal is detected, and a phase adjuster substantially continuously detects and cancels undesired phase shifts in the detected signal caused by elements in the radio chain. A specific, example embodiment of the present invention is provided in a Cartesian feedback system wherein the phase of the feedback signal is detected and aligned with the phase of the original modulated signal, providing uncorrupted I and Q baseband feedback signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.