Granted Patent
Utility
US 4,433,396 · App. 06/300,128
Sonar receivers
Inventors:
Phillip Johnson, John Robert Walden
Patented Case
View Patent ↗
Granted: Feb 21, 1984
Filed: Sep 8, 1981
Inventors
Phillip Johnson
John Robert Walden
Assignee (at issue)
Plessey Overseas Limited
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.