Granted Patent
Utility
US 5,381,473 · App. 07/968,180
Noise cancellation apparatus
Inventors:
Douglas Andrea, Martin Topf
Patented Case
View Patent ↗
Granted: Jan 10, 1995
Filed: Oct 29, 1992
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.