Estimator for estimating an operating defect in a quadrature modulator, and a modulation stage using the estimator
US5663691A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 1996 |
| Grant date | Sep 2, 1997 |
| Priority date | — |
| Expiry date | Jan 11, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2071
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An estimator for estimating an operating defect in a quadrature modulator, including two mixers to which respective carrier signals are applied, and to which respective modulating signals are also applied. The output signals from the mixers are applied to a summing circuit so as to constitute a modulated signal. The estimator includes detection circuitry for detecting the instantaneous power of said modulated signal; multiplication circuitry for multiplying the detected instantaneous power by at least one of the modulating signals; and integration circuitry for integrating the result of the multiplication and for supplying a signal indicative of the operating defect of the modulator. The modulator is particularly applicable to removing the residual amount of the carrier signals that remains in the modulated signal, and to correcting the quadrature between the signals output by the mixers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.