Method of predicting voltages in telephone line measurement
US5444759A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 20, 1993 |
| Grant date | Aug 22, 1995 |
| Priority date | — |
| Expiry date | Sep 20, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M3/30
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
For measuring characteristics (resistance, capacitance, and foreign voltage) on a telephone line, source voltages are coupled via source resistances to the line in three test conditions and the parameters are calculated from steady state voltages at the terminals of the line. Each steady state voltage is predictively calculated from nine samples of the voltage at the terminal using a closed form second order solution of a circuit model of the telephone line derived from a transformation of the circuit model into the Z domain and using the matched pole-zero technique. The steady state voltages can thus be determined without waiting for transients, due to the time constants of the telephone line, to die out, resulting in much faster measurements for telephone lines with large time constants.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.