The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 26, 1982
Filed:
Oct. 29, 1979
Applicant:
Inventor:
Richard E DeFreitas, Westford, MA (US);
Assignee:
DeltaLab Research, Inc., Chelmsford, MA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03K / ;
U.S. Cl.
CPC ...
375 28 ; 332 / ; 375 26 ;
Abstract
In an electrical system for generating a digitally-encoded signal from an analog signal and a reference signal, a circuit for reducing quantization noise comprises a bandpass filter which passes audible frequency components, the output of which filter is used to adjust the encode signal so as to reduce the level of audible components in a signal decoded from the encoded one.