Granted Patent
Utility
US 4,667,178 · App. 06/571,271
Digital to analog converter
Inventor:
Kazuo Ryu
Patented Case
View Patent ↗
Granted: May 19, 1987
Filed: Jan 16, 1984
Inventor
Kazuo Ryu
Assignee (at issue)
NEC 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.