Electronically controllable slope equalizer
US6580327B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 28, 2002 |
| Grant date | Jun 17, 2003 |
| Priority date | — |
| Expiry date | Feb 28, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G1/0088
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The present invention provides a slope equalizer for use in a voice frequency channel card, which is preferably electronically and remotely controllable, and retrocompatible with existing telecommunication systems. The slope equalizer of the invention includes a high-pass filter followed by a variable gain stage amplifier, where the variable gain stage amplifier is an operational amplifier with a plurality of parallel input signal paths, each of the signal paths being a series-connected resistor and switch. The switch is preferably a FET transistor that is electronically and, optionally, remotely controllable. The circuit topology allows the use of FET transistors having relatively high on-resistances. A further advantage of the topology is that the FET switches are connected to a virtual ground by way of an operational amplifier, thereby reducing on-resistance modulation caused by signal variations across the FET.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.