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:
Sep. 07, 1993
Filed:
Feb. 21, 1992
U.S. Philips Corporation, New York, NY (US);
Abstract
A sigma-delta modulator comprising a low-pass filter of the Nth order, which is constituted by a series combination of N first-order integrating sections (6.1, 6.2, 6.3, . . . , 6.N) each comprising an integrator (12.1, 12.2, 12.3, . . . , 12. N) and a limiter (14.1, 14.2, 14.3, . . . , 14.N). The individual output signals of the sections are weighted by means of corresponding weighting amplifiers (16.1, 16.2, 16.3, . . . , 16.N) and the weighted signals are added together by an adder stage (18). The gains of the sections and the limit values of the limiters are selected so that the last limiter (14.N) in the series arrangement is activated first as the input signal level to the sigma-delta modulator increases, then the last-but-one limiter, and so on. This reduces the order of the filter system each time by one section as the input signal level increases above each successive limit value, thereby causing the sigma-delta modulator to remain stable at all signal levels.