Image reject transceiver and method of rejecting an image
US6137999A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 24, 1997 |
| Grant date | Oct 24, 2000 |
| Priority date | — |
| Expiry date | Dec 24, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/28
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An image reject transceiver (10) provides both phase and gain adjustments that causes unwanted images to be rejected. A reference signal (RF.sub.IN) is frequency translated by two mixer circuits (28, 34) in a receiver circuit (16) to provide both an in-phase and an out-of-phase replica signal of the reference signal (RF.sub.IN) during normal operation. In a calibration mode a single frequency generated by a transmitter VCO (22) replaces the reference signal (RF.sub.IN). A phase detector circuit (38) provides a phase difference value that is fed back through a first switch (45) to a phase shift circuit (36) for adjusting the phase separation between the two replica signals. An amplitude detector circuit (40) provides an amplitude error value that is fed back through a second switch (47) to the mixer circuit (34) for adjusting and matching the gain of the two replica signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.