Process and circuit to determine estimates of the instantaneous value of parameters of at least one sinusoidal signal with constant and known frequency which is an additive component of a measuring signal
AssigneeLandis & Gyr Betriebs AG
InventorsPeter Gruber, Jurg Todtli
Life of this patent
Estimating the term…
Abstract
A circuit and method for iteratively estimating Fourier coefficients of one or more Fourier components of a measuring signal utilizes a filter to determine the Fourier coefficients for sampling time k-1. The coefficients are utilized to obtain an estimate of the measuring signal at sampling time k. A subtractor circuit subtracts an actual sample of the measuring signal at sampling time k from the estimate of the measuring signal at sampling time k to obtain a difference signal. The difference signal is inputted back into the filter to determine an estimate of the Fourier coefficients at sampling time k.
Claims19
A process for iteratively determining estimated instantaneous values of Fourier coefficients characteristic of one or more sinusoidal components of constant and known frequency which are additive components of a measuring signal comprising the steps of:
- utilizing a filter circuit to output and store first estimated values of the Fourier coefficients of said sinusoidal components at a sampling time k-1
- utilizing said filter circuit to process said first estimated values to obtain an estimate of said measuring signal for the sampling time k,
- subtracting by means of a subtracting circuit element the estimate of the measuring signal at sampling time k from an actual sample of the measuring signal at sampling time k to generate a difference signal,
- inputting said difference signal into said filter circuit, and
- utilizing said difference signal in said filter circuit to correct the stored first estimated values of the Fourier coefficients for sampling time k-1 to obtain instantaneous second estimated values of the Fourier coefficients for sampling time k.
A circuit for iteratively determining estimates of instantaneous values of Fourier coefficients characterizing one or more sinusoidal components of constant and known frequency which are additive components of a measuring signal, said circuit comprising
- a subtractor for subtracting an estimated sample of the measuring signal from an actual sample of the measuring signal to generate a difference signal for a particular sampling time,
- a correction circuit connected to an output of said subtractor and comprising multiplier means for multiplying said difference signal for the particular sampling time by a plurality of time variable coefficients, and
- a signal model circuit connected to said correction circuit and to said subtractor for generating and storing signals representative of updated estimated values of Fourier coefficients of said sinusoidal components by adding the outputs of said correction circuit to previous estimated values of said Fourier coefficients and for producing said estimated sample of said measuring signal for use by said subtractor for a next sampling time by multiplying said updated estimated value of Fourier coefficients by sine and cosine functions and adding the outputs.
An estimation circuit for interatively determining estimated instantaneous values of Fourier coefficients characterizing one or more sinusoidal components of constant and known frequency which are additive components of a measuring signal comprising
- means for storing first signals representative of the Fourier coefficients of said sinusoidal components at a sampling time k-1,
- first processing means for processing said first signals to obtain an estimate signal corresponding to an estimate of said measuring signal at a sampling time k,
- means for generating an actual signal corresponding to an actual sample of the measuring signal at the sampling time k,
- subtractor means for subtracting said estimate signal and actual signal to obtain a difference signal, and
- second processing means for processing said first signals and said difference signal to correct said first signals to obtain second signals representative of said Fourier coefficients of said sinusoidal components at the sampling time k.
Dependencies are inferred from the claim text.