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. 31, 1994
Filed:
Jun. 24, 1992
Irving W Cahalan, Huntington Station, NY (US);
Michael La Clair, Yapank, NY (US);
Paul Seiter, Middle Village, NY (US);
John Weber, Northport, NY (US);
Hazeltine Corporation, Greenlawn, NY (US);
Abstract
A portable test receiver for field maintenance of a remote sensor monitoring system for underground transformers. The apparatus uses a phase locked loop method to demodulate the DPSK modulation of the remote monitor transmitter. The apparatus is battery operated and easily moved to permit monitoring of spot networks and critical locations for maintenance work. The apparatus features a single software driven display offering good visibility with low current drain. Decoding the transmitter signal is accomplished by using the crystal oscillator circuit of the transmitter is used to generate a reference which is compared to the transmitter signal to detect phase flips. Since the apparatus is battery-powered, there is no AC power to provide 'zero' crossing points of the monitored transmitter. Bit timing is provided by taking advantage of the nulls at the 60 cycle 'zero' crossings found in the transmitter signal.