Patent ID: 9239349
Filing Date: 2016-01-19
CPC Classification: G01R

Claim Text:
1. A method of monitoring electromagnetic interference in equipment under test, the method comprising: capturing and/or generating a plurality of time domain waveforms from the equipment under test, and a plurality of scatter plots; storing the plurality of captured and/or generated time domain waveforms and scatter plots; applying a fast fourier transform (FFT) to each of the stored time domain waveforms as it is received thereby to produce FFT outputs; storing the FFT outputs in a database; generating a statistically representative spectrograph or spectrogram in the frequency domain based on at least the stored FFT outputs and scatter plots or data associated with the scatter plots, combining constituent FFTs of the statistically representative spectrograph or spectrogram in such a manner as to emulate a spectrum that is produced by an EMI (Electromagnetic Interference) receiver or spectrum analyzer; combining resultant outputs from a number of iterations of this process to produce an EMI spectrum that is substantially statistically equivalent to an actual EMI spectrum associated with a signal source under examination, determining from each scatter plot, a total pulse count; passing, at each frequency point under consideration, the corresponding value from each FFT in the spectrogram, in a sequence determined by a sequencing array, to a cascaded first-order infinite impulse response (IIR) filter at suitable timing determined by the determined total pulse count; combining outputs of the IIR filter to produce a final quasi-peak spectrum; passing, at each frequency point under consideration, the corresponding value from each FFT in the spectrogram to a peak detector algorithm; and combining outputs of the peak detector algorithm to produce a final peak spectrum, wherein the substantially statistically equivalent EMI spectrum and the final peak spectrum provide a convenient and a cost effective way to monitor EMI signals.