The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 05, 1997
Filed:
Dec. 03, 1993
Russell A Hershbarger, Nevada City, CA (US);
Eric Davies, Grass Valley, CA (US);
Silicon Systems, Inc., Tustin, CA (US);
Abstract
A method and apparatus for communicating a modulated signal across an isolation barrier using capacitors is provided. The present invention allows low distortion communication of an audio signal across an isolation barrier without the need for a large and bulky isolation transformer. The present invention may be used to provide telephone line isolation for modem applications compliant with governmental regulations. A line interface integrated circuit (IC) may be connected directly to a telephone line and powered by the telephone line. The line interface IC may include a sigma delta modulator to communicate the receive signal across a capacitor over an isolation barrier and a digital-to-analog (D/A) converter to provide an analog transmit signal from a sigma delta bit stream communicated across a capacitor over an isolation barrier. Circuitry on the opposite side of the isolation barrier includes similar components to process the transmit and receive signals.