Apparatus and method for real time harmonic spectral analyzer

Abstract

In one embodiment, a measuring device may comprise two oscillators. The first oscillator may generate a local reference signal in a frequency detector to detect a fundamental frequency of the AC. The second oscillator may generate two substantially mutually orthogonal sinusoid signals having the selected frequency. The measuring device further may comprise a first group of multipliers that mixes the two sinusoid signals with a current and a voltage data signal of the AC respectively, a group of low-pass filters for removing high frequency components from the multiplication products, a second group of multipliers for mixing the filtered multiplication produces respectively, and a plurality of adders each to sum together a pair of multiplication products of the second group of multipliers.

1 . A device for measuring power of an alternating current (AC) with respect to a selected frequency, comprising:
 a frequency detector having a first oscillator to generate a local reference signal to detect a fundamental frequency of the AC; and   a power analyzer to analyze power of the AC, the power analyzer comprising:
 a second oscillator to generate first and second substantially mutually orthogonal sinusoid signals at the selected frequency; 
 a first group of multipliers for mixing the first and second sinusoid signals with a current data signal and a voltage data signal of the AC respectively; 
 a group of low-pass filters for respectively removing high frequency components from a multiplication product of the first group of multipliers; 
 a second group of multipliers for respectively mixing the filtered multiplication products; and 
 a plurality of adders each to sum together a pair of multiplication products of the second group of multipliers. 
   
     
     
         2 - 31 . (canceled)