Granted Patent
Utility
US 6,370,244 · App. 09/054,872
Efficient digital ITU-compliant zero-buffering DTMF detection using the non-uniform discrete fourier transform
Inventors:
Matthew D. Felder, James C. Mason, Brian Evans
Patented Case
View Patent ↗
Granted: Apr 9, 2002
Filed: Apr 3, 1998
Inventors
Matthew D. Felder
James C. Mason
Brian Evans
Assignee (at issue)
BOARD OF REGENTS, THE UNIVERSITY OF TEXAS SYSTEM
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.