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:
Aug. 15, 1995
Filed:
Oct. 25, 1993
H Spence Jackson, Austin, TX (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A bandpass sigma-delta analog-to-digital converter (ADC) (10) includes first (11) and second (12) bandpass sigma-delta modulators, and a digital filter (13) connected to digital outputs thereof. In the illustrated embodiment, the first bandpass sigma-delta modulator (11) is a second-order, single bit bandpass modulator, and the second bandpass sigma-delta modulator (12) is a first-order, multiple-bit modulator. Coefficients in feedback paths of the first (11) and second (12) modulators are derived from a transfer function of the digital filter. In one embodiment, a receiver (50) for a system such as frequency modulation (FM) radio converts an intermediate frequency (IF) analog signal to digital in-phase (I) and quaternary (Q) signals using the bandpass sigma-delta ADC (10).