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:
Mar. 06, 2007
Filed:
Oct. 02, 2002
Martin C. Sinha, Southampton, GB;
Lucy M. Macgregor, Southampton, GB;
Martin C. Sinha, Southampton, GB;
Lucy M. MacGregor, Southampton, GB;
University of Southampton, Southampton, GB;
Abstract
An apparatus for generating electronic signals for application in subsea electromagnetic exploration. A surface generated high-voltage low-current source signal stabilized at a first frequency is supplied to a deep-tow vehicle () via an umbilical cable (). The high-voltage low-current signal is transformed at the deep-tow vehicle to a high-current low-voltage a.c. signal by a transformer () within a cycloconverter (). A semiconductor relay bridge () provides switchable rectification of the high-current low-voltage a.c. signal to provide a quasi-square wave at a second frequency, lower than the first frequency, for supply to a transmitting antenna () towed by the deep-tow vehicle. The times of the rectification switching are dependent on zero crossings of the high-current low-voltage a.c. signal. Allowable rectification switching times may be gated to occur only within pre-determined time windows to avoid noise-induced zero-crossing switching. The apparatus allows multiple transmission frequencies to be derived from a single stabilized source and improves spectral integrity by avoiding rectification switching at zero-crossings not occurring at the first frequency.