Terminating circuit in a battery feed circuit of an electronic exchange system
US4982422A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 19, 1989 |
| Grant date | Jan 1, 1991 |
| Priority date | — |
| Expiry date | Sep 19, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M19/005
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Disclosed is a terminating circuit in a battery feed circuit of an electronic exchange system. The battery feed circuit comprises two transconductance amplifiers connected by a coupling capacitor, for supplying a direct current through a ring terminal and a tip terminal to a load. Each of the transconductance amplifiers comprises an operational amplifier; a resistor connected between the output end of the operational amplifier and the tip terminal or the ring terminal, and an impedance unit connected between the inverting input terminal of the operational amplifier and the output end. The impedance unit has an impedance determined in such a way that the required terminating impedance of the battery feed circuit when viewed from the tip terminal and the ring terminal is formed only by the internal elements including the impedance means and the resistor, whereby an external larger-size capacitance capacitor for matching becomes unnecessary.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.