Granted Patent
Utility
US 4,254,436 · App. 05/934,829
Noise cancellation circuit
Inventor:
Jack R. Harford
Patented Case
View Patent ↗
Granted: Mar 3, 1981
Filed: Aug 18, 1978
Inventor
Jack R. Harford
Assignee (at issue)
RCA 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.