Phase and amplitude equalization arrangement
US5557640A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 30, 1994 |
| Grant date | Sep 17, 1996 |
| Priority date | — |
| Expiry date | Jun 30, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B7/005
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An equalisation arrangement compensates for multipath phase and amplitude distortion effects in a transmission channel by first measuring such distortion effects as they occur over time in a calibration phase, thereby obtaining phase and amplitude compensation factors, then applying these factors to a correcting circuit situated in the signal path of the receiver at the appropriate times during a subsequent data transmission phase. Calibration is achieved by feeding a received calibration signal to an amplifier, preferably a successive detection logarithmic amplifier (26), comparing the phase of the limited linear output of the logarithmic amplifier with a delayed version of itself (30, 28), and using the amplitude information (39) in the logarithmic output (72) of the logarithmic amplifier (26) and the phase-change information (35) resulting from the phase comparison to compute the phase and amplitude compensation coefficients. In the data transmission phase, the compensation coefficients are applied to amplifiers and multipliers, etc (56, 55), in the correcting circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.