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:
May. 10, 1994
Filed:
May. 12, 1993
Applicant:
Inventors:
Paul F Ferguson, Jr, Tewksbury, MA (US);
Apparajan Ganesan, Salem, NH (US);
Robert W Adams, Acton, MA (US);
Assignee:
Analog Devices, Inc., Norwood, MA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03M / ;
U.S. Cl.
CPC ...
341143 ; 375 28 ;
Abstract
A separate filter circuit is inserted between the D/A converter and the summing junction in the feedback path of a conventional sigma delta modulator. This additional filter allows control of the quantization noise transfer function profile independently of the forward signal transfer function. By proper tailoring of the transfer functions a third or higher order modulator can be constructed without instability developing. The modulator can also be constructed as a completely digital circuit and used as a noise shaping circuit in a digital digital-to-analog converter.