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:
Dec. 24, 2002
Filed:
Apr. 07, 2000
Applicant:
Inventors:
Assignee:
Sumitomo Electric Industries, Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01R 3/302 ;
U.S. Cl.
CPC ...
G01R 3/302 ;
Abstract
A SQUID bias current adjustment device supplies a sinusoidal current at 40 kHz, for example, to a coil to generate magnetic field at a SQUID. The amplitude of the field corresponds to a half period of a field-voltage characteristic. Voltage generated from the SQUID at this time is filtered by using a filter to pick out components of 40 kHz and 80 kHz. The picked out signal components are rectified and converted to direct current, and the bias current is adjusted such that the maximum value is obtained. In this way, a SQUID bias current adjustment device can be provided capable of automatically adjusting bias current properly in a short period of time.