Granted Patent
Utility
US 6,581,080 · App. 09/549,403
Digital filters
Inventor:
David Charles William Richards
Patented Case
View Patent ↗
Granted: Jun 17, 2003
Filed: Apr 14, 2000
Inventor
David Charles William Richards
Assignee (at issue)
SONY UNITED KINGDOM 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.