Modulation signal calibration between modem and radio using loopback
US5890057A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 27, 1996 |
| Grant date | Mar 30, 1999 |
| Priority date | — |
| Expiry date | Nov 27, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/20
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A radio-frequency output signal having a specified characteristic is produced using a combination of a calibrated radio unit in which a calibration factor is stored and an uncalibrated modem unit. The calibration factor is input to the modem unit from the radio unit, and the modem outputs to the radio unit a signal of a nominal signal level determined in accordance with the calibration factor. An actual signal level of the signal is measured, and a gain factor within the modem unit is adjusted until the nominal signal level and the actual signal level are substantially equal. A wireless modem includes a calibrated radio unit and an uncalibrated modem unit coupled to the radio unit. A first signal path is provided from the modem unit to the radio unit, and a feedback signal path from the radio unit to the modem unit. The modem unit includes control circuitry for outputting across the first signal path a signal that is nominally of a desired signal level, and for adjusting a nominal signal level of the signal in accordance with information received across the feedback signal path.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.