Patent ID: 6907128
Filing Date: 2005-06-14
Classification: G01G,H03H

Abstract:
1. A noise canceling apparatus for weight measurement for eliminating a fixed-period vibration noise contained in a quantitative signal, said quantitative signal being a result of digitization of a signal obtained by detecting a weight of an object to be measured, said apparatus comprising: a band pass filter for filtering a frequency component of said quantitative signal at a plurality of notches, said filtering using variable filter coefficients; and a coefficient control section for calculating a series of said filter coefficients, and supplying said series to said band pass filter, wherein said band pass filter has a frequency characteristic including said plurality of notches, and a transfer function of said band pass filter includes a product of a plurality of factors each having a root corresponding to each one of said plurality of notches, said coefficient control section comprising: a frequency changing element for changing a frequency component of a root as a part of a factor, said root corresponding to a notch selected from said plurality of notches; an expansion element for expanding a product of a plurality of factors in a polynomial, said product constituting said transfer function of said band pass filter; and a coefficient calculating element for calculating a series of said filter coefficients on the basis of said polynomial.