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:
May. 08, 1984
Filed:
Mar. 22, 1982
Hitachi, Ltd., Tokyo, JP;
Nippon Telegraph & Telephone Public Corporation, Tokyo, JP;
Abstract
A testing system connects a subscriber line to be tested by way of a semiconductor switch of a type driven by a constant current to a test equipment to test a subscriber line and a terminal equipment. The test system includes a compensation circuit having means for measuring a constant current component contained in a current flowing through the semiconductor switch into a test line, and means for drawing a constant current component to drive the switch through the test line on the basis of the measuring result to supply the current component obtained by subtracting the constant current component from the current flowing through the test line to the testing equipment.