Quadrature signal generator having digitally-controlled phase and amplitude correction
US4696017A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 1986 |
| Grant date | Sep 22, 1987 |
| Priority date | — |
| Expiry date | Feb 3, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03B27/00
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A digitally-controlled quadrature signal generator is provided having a frequency synthesizer for receiving a digital input signal and in response thereto generating an output signal having a predetermined frequency. The output signal is split to produce an in-phase (I) signal and a quadrature-phase (Q) signal. A first table look-up memory is provided for generating a predetermined phase correction signal for use in cancelling any phase error in the quadrature-phase signal. A mixer receives the phase correction signal and the in-phase signal and in response thereto generates a phase error signal. The phase error signal is then added to the quadrature-phase signal to thereby cancel the undesirable phase error. Moreover, programmable attenuator circuits or limiter circuits are provided to limit the in-phase and quadrature-phase signals and thereby cancel any undesirable amplitude error components therein.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.