Data signal attenuator and systems and methods for using same
US6697485B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 10, 1998 |
| Grant date | Feb 24, 2004 |
| Priority date | — |
| Expiry date | Nov 10, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/76
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The present invention provides apparatus and methods for attenuating signals received from a source over a data transmission line, having an unknown resistance, to achieve optimized signals in various data terminal and data communications equipment. In a preferred embodiment, a resistor network is operably coupled between the transmission line and a means for processing the signal, such as a digital processor, an ADC and a DAC. The resistor network comprises a termination resistor that is associated with a termination voltage, a variable resistor and another resistor. During use, a switch is operably positioned between a plurality of switch positions so that two voltage measurements will lead to the determination of the voltage of the source and the termination voltage within the resistor network. Once these voltages are known, the unknown resistance can be estimated. Thereafter, the length of the transmission line may be determined because of known resistance-per-unit-distance characteristics of the transmission line. In response to knowing this length, the digital processor selects a desired resistance value for the variable resistor so that, upon adjustment of the variable resis…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.