Granted Patent
Utility
US 4,390,754 · App. 06/265,983
Tone generator circuit
Inventor:
Douglas R. Holberg
Patented Case
View Patent ↗
Granted: Jun 28, 1983
Filed: Jun 30, 1980
Inventor
Douglas R. Holberg
Assignee (at issue)
Mostek 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.