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:
Mar. 04, 1986
Filed:
Jun. 22, 1984
Manley J Head, Wylie, TX (US);
Rockwell International Corporation, El Segundo, CA (US);
Abstract
A quadrature amplitude modulation (QAM) demodulator system has in-phase and quadrature channel detectors receiving local oscillator signals which must be in precise phase quadrature relationship with each other. The in-phase and quadrature channels each have analog-to-digital converters with n output bits, where n is greater than m, the number of bits required for the data output for each channel. The n-m less significant bits in one channel are used to derive a signal indicating the deviation from a true quadrature relationship between the local oscillator signals. The error signal controls an adjustment of the phase of one of the local oscillator signals, to bring about the precise quadrature relationship required for accurate demodulation.