Granted Patent
Utility
US 4,813,073 · App. 07/069,250
Echo cancellation
Inventor:
Fuyun Ling
Patented Case
View Patent ↗
Granted: Mar 14, 1989
Filed: Jul 2, 1987
Inventor
Fuyun Ling
Assignee (at issue)
Codex 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.