Voice frequency repeater and term sets and other circuits therefor
US4331842A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 11, 1980 |
| Grant date | May 25, 1982 |
| Priority date | — |
| Expiry date | Feb 11, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/586
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An electronic hybrid voice frequency repeater having a pair of term sets interconnected by a four-wire circuit for separating the two directions of signal transmission and amplifying each direction separately. Each term set couples the repeater's four-wire circuit to a two-wire line and has a differential current driver for driving the two-wire line and a differential amplifier connected in a feedback loop for sensing the differential signal voltage across the two-wire line, to drive the current driver and to feed an incoming differential signal on the two-wire line to the repeater's four-wire circuit while nulling signals arriving at the term set from the four-wire circuit to prevent them from returning to the four-wire circuit. Other features disclosed include a low frequency clamping circuit, an adjustable-gain amplifier, and an equalizer for non-loaded cable.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.