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.

Date of Patent:
Nov. 10, 1998

Filed:

May. 01, 1997
Applicant:
Inventors:

Paul Klatser, Markelo, NL;

Egbert Jan Kruisdijk, Enschede, NL;

Assignee:

Fluke Corporation, Everett, WA (US);

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03F / ;
U.S. Cl.
CPC ...
330126 ; 330 59 ; 330 84 ; 330308 ;
Abstract

A voltage isolation circuit having an improved method of combining the HF path and LF path is provided. The LF path comprises an opto-isolator to achieve voltage isolation of the input signal while passing low frequencies. The HF path comprises a transformer to achieve voltage isolation of the input signal while passing high frequencies. The HF path and LF path are combined at a summing node to obtain an isolated input signal. Obtaining a flat frequency response requires that the cross-over frequency between the LF path and HF path be closely matched. A portion of the LF path is injected into the HF path such that LF components are canceled out in the region of the transition frequency. In this way, the pole frequency of the transformer in the HF path may be compensated for to achieve a flat frequency response for the combined LF and HF paths.


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