Gain linearizer for variable gain amplifiers
US6711391B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 10, 2000 |
| Grant date | Mar 23, 2004 |
| Priority date | — |
| Expiry date | Dec 14, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G7/08
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Techniques to linearly (in dB) adjust the gains of variable gain elements (i.e., variable gain amplifiers or VGAs) in a receiver or transmitter. An input control signal is provided to a conditioning circuit that conditions the control signal to achieve various signal characteristics. The input control signal is limited to within a particular range of values, temperature compensated, scaled (or normalized) to the supply voltages, shifted with an offset, or manipulated in other fashions. The conditioned signal is then provided to an input stage of a linearizer that generates a set of exponentially related signals. This is achieved using, for example, a differential amplifier in which the conditioned control signal is applied to the inputs of the differential amplifier and the collector currents from the differential amplifier comprises the exponentially related signals. An output stage within the linearizer receives the exponentially related signals and, in response, generates a gain control signal. By approximately matching the output stage to a gain stage of the variable gain element and by using the gain control signal generated by output stage, the gain transfer function of the V…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.