Granted Patent
Utility
US 4,437,087 · App. 06/343,355
Adaptive differential PCM coding
Inventor:
David W. Petr
Patented Case
View Patent ↗
Granted: Mar 13, 1984
Filed: Jan 27, 1982
Inventor
David W. Petr
Assignee (at issue)
Bell Telephone Laboratories, Inc.
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.