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. 02, 2004
Filed:
Feb. 19, 2002
Michael A. Mayor, Fort Wayne, IN (US);
David W. Lagrow, Fort Wayne, IN (US);
ITT Manufacturing Enterprises, Inc., Wilmington, DE (US);
Abstract
An EMI testing scheme involves analyzing an analog input signal in frequency band segments. The input signal is passband filtered and digitally sampled before being converted to a complex analytic signal via a Hilbert transform filter and then transformed into a frequency domain signal via a Discrete Fourier Transform (DFT). Pre-stored frequency window filters are then applied to the frequency domain signal. The set of discrete filter sample points which form the window filters are designed such that particular frequency sub-bands of a desired bandwidth within the frequency segment are selected for EMI analysis. By applying different frequency window filters to the frequency domain signal, different frequency sub-bands are sequentially selected for analysis. An inverse DFT transforms the filtered signal back to the time domain, and the peak voltage of the time domain signal is compared with a threshold to determine whether EMI levels within the selected sub-band are acceptable.