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:
Jun. 08, 2004
Filed:
Oct. 08, 1999
Kevin J. McCall, Lafayette, CO (US);
STMicroelectronics, Inc., Carrollton, TX (US);
Abstract
A method is provided for determining the actual amplitude of a signal relative to a predetermined amplitude. According to the method, two samples of the signal are squared to produce two squared samples, and the sum of the two squared samples minus the square of the predetermined amplitude is calculated to produce a difference of squares. A shift operation is performed on the difference of squares to determine a difference between the actual amplitude and the predetermined amplitude. In a preferred embodiment, two consecutive samples of the signal are taken at four times the frequency of the signal. Also provided is a circuit device that includes an A/D converter, a variable gain amplifier, and a feedback loop. The A/D converter converts an analog signal into a digital signal, and the variable gain amplifier adjusts the amplitude of the analog signal. The feedback loop controls the variable gain amplifier based on a difference between the amplitude of the analog signal and a predetermined amplitude. Further, the feedback loop calculates the difference by squaring two samples of the digital signal, summing the two squared samples and subtracting the square of the predetermined amplitude to produce a result, and shifting the result.