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. 19, 1995
Filed:
Oct. 07, 1994
James D Hagerty, Tiverton, RI (US);
The United States of America as represented by the Secretary of the Navy, Washington, DC (US);
Abstract
The balanced, bi-directional calibration circuit of the present invention joined to a sensor and a differential preamplifier. The sensor has two outputs which are received by the differential preamplifier such that common-mode line noise is rejected. The calibration circuit includes a broadband signal generator which provides the calibration signal. The calibration circuit also includes a switching network that allows the calibration signal to be switched to either of the two sensor outputs or isolated from the sensor and preamplifier. A dual-state switching control signal is applied via a single control wire to the switching network to select which preamplifier input receives the calibration signal. The calibration signal generator control line is electrically isolated from the preamplifier by an opto-isolator. The electrical balance of the bi-directional calibration circuit and electrical isolation of the calibration signal generator preserve the common-mode noise rejection of the differential preamplifier.