Granted Patent
Utility
US 5,809,133 · App. 08/653,283
DTMF detector system and method which performs frequency domain energy calculations with improved performance
Inventors:
John G. Bartkowiak, Zheng Xie
Patented Case
View Patent ↗
Granted: Sep 15, 1998
Filed: May 24, 1996
Inventors
John G. Bartkowiak
Zheng Xie
Assignee (at issue)
Advanced Micro Devices, 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.