Granted Patent
Utility
US 4,968,989 · App. 07/040,168
Switched capacitor filter for use with a digital-to-analog (D/A) converter
Inventors:
John A. Olmstead, Salomon Vulih
Patented Case
View Patent ↗
Granted: Nov 6, 1990
Filed: Apr 20, 1987
Inventors
John A. Olmstead
Salomon Vulih
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.