公开(公告)号：US20030215100A1

公开(公告)日：2003-11-20

申请号：US10436075

申请日：2003-05-13

Applicant: Ishida Co., Ltd.

Inventor： Takashi Kimura ,  Masayoshi Nakajima ,  Shuuji Murata ,  Yukio Wakasa ,  Kazuhiro Suhara

IPC: A61F011/06 ,  G10K011/16 ,  H03B029/00

CPC classification number: H03H17/025 ,  G01G3/147 ,  G01G23/10 ,  H03H17/0294

Abstract: A noise canceling apparatus (1) comprises an amplifier (10) for amplifying a measured signal (ms) outputted from a measuring device (3), an analog filter (11), an ADC (12), a digital filter (14), a coefficient control section (13), and a data input section (15). The digital filter (14) is a notch filter for attenuating a frequency component of a quantitative signal D(n) outputted from the ADC (12) at a plurality of notches (stop bands). A transfer function of the digital filter (14) is expressed by the product of a plurality of factors each having a root that corresponds to each one of the plurality of notches. The coefficient control section (13) changes a frequency component of a root corresponding to a notch selected from the plurality of notches, and thereafter, expands in a polynomial the transfer function of the reconstructed digital filter (14). On the basis of the polynomial thereby obtained, a new series of filter coefficients is calculated. A filter characteristic is controlled in such a manner that it conforms to a frequency variation of a fixed-period vibration noise, whereby the fixed-period vibration noise that varies in frequency is attenuated with a high degree of precision.

Abstract translation: 噪声消除装置（1）包括用于放大从测量装置（3）输出的测量信号（ms）的放大器（10），模拟滤波器（11），ADC（12），数字滤波器（14）， 系数控制部（13）和数据输入部（15）。 数字滤波器（14）是用于衰减在多个凹口（停止频带）处从ADC（12）输出的定量信号D（n）的频率分量的陷波滤波器。 数字滤波器（14）的传递函数由多个因子的乘积表示，每个因子各自具有与多个凹口中的每一个相对应的根。 系数控制部（13）改变与从多个切口中选择的切口对应的根的频率分量，然后以多项式扩大重构的数字滤波器（14）的传递函数。 根据得到的多项式，计算出一系列新的滤波器系数。 控制滤波器特性使其符合固定周期振动噪声的频率变化，由此频率变化的固定周期振动噪声以高精度衰减。