Granted Patent
Utility
US 5,825,897 · App. 08/912,459
Noise cancellation apparatus
Inventors:
Douglas Andrea, Martin Topf
Patented Case
View Patent ↗
Granted: Oct 20, 1998
Filed: Aug 18, 1997
Inventors
Douglas Andrea
Martin Topf
Assignee (at issue)
Andrea Electronics Corporation
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.