US 6,665,403 B1 · Digital gyrator

Abstract

A digital device for controlling the DC line current on a telephone line which includes a digital device that utilizes a digital filter for setting the DC line current. By controlling the DC line current digitally, software can be used to set the DC line current in accordance with predefined characteristics. Predefined characteristics can be set to accommodate varying country specifications instead of using switches to control resistors and capacitors. In addition, changes in a country's requirements can be accomplished through software, instead of changing components or redesigning a circuit board. The device also incorporates a method for maintaining DC current level during changes in digital filter characteristics. The use of software results in increased flexibility by allowing an infinite number of settings via software or software updates, and allowing changes to be made quickly and easily throughout the world.

Claims23

Dependent claims

A method for regulating the DC line current on a telephone line, comprising the steps of:

interfacing a telecommunication device with a telephone company central office;
deriving a first analog signal from said telecommunication device which is representative of the existing DC voltage across said telecommunication device;
converting said first analog signal to a first digital signal;
filtering said first digital signal to derive a second digital signal, said filtering step comprising at least changing filtering characteristics at a predetermined time point during filtering of said first digital signal;
converting said second digital signal to a second analog signal;
and
regulating a current source with said second analog signal, wherein said current source controls the DC line current on the telephone line.

4 more elements

Dependencies are inferred from the claim text.

Digital gyrator

Life of this patent

Digital gyrator

Life of this patent

Abstract

Claims23