Abstract: It is an object of the present invention to provide techniques which allow for easier change in filter characteristics of a digital filter. Then, in order to attain this object, in a weighing device according to the present invention, a filter coefficient calculator (6) calculates a filter coefficient using a predetermined mathematical expression and outputs the result to a signal processor (5). The signal processor (5) carries out a filtering process on a weight signal (DS) of a digital signal using the filter coefficient. The mathematical expression includes a first parameter which specifies an amount of attenuation in at least one attenuation band where attenuation should be locally intensified in a stopband of amplitude characteristics of the filtering process, a second parameter which specifies the band position of the at least one attenuation band, and a third parameter which specifies a starting frequency of the stopband.

Abstract: It is an object of the present invention to provide techniques which allow for easier change in filter characteristics of a digital filter. Then, in order to attain this object, in a weighing device according to the present invention, a filter coefficient calculator (6) calculates a filter coefficient using a predetermined mathematical expression and outputs the result to a signal processor (5). The signal processor (5) carries out a filtering process on a weight signal (DS) of a digital signal using the filter coefficient. The mathematical expression includes a first parameter which specifies an amount of attenuation in at least one attenuation band where attenuation should be locally intensified in a stopband of amplitude characteristics of the filtering process, a second parameter which specifies the band position of the at least one attenuation band, and a third parameter which specifies a starting frequency of the stopband.

Abstract: A filtering technique which makes it possible to easily and appropriately eliminate a noise without increasing a scale of a circuit necessary for a filtering process even if a noise frequency is liable to be changed is provided. A filter coefficient calculator (6) of a weight measurement apparatus calculates filter coefficients using a predetermined arithmetic expression and outputs them to a signal processor (5). The signal processor (5) carries out a filtering process on a weighing signal (Ds) using the filter coefficients. The arithmetic expression includes a parameter specifying a band position of an attenuation band where attenuation must be locally enhanced. A user can input a value of the parameter via a data entry part (7). In this manner, the filter coefficients can be changed by using a parameter specifying the band position of the attenuation band which is physical and thus easy to grasp.

Abstract: A filter coefficient calculator of a weight measurement apparatus calculates filter coefficients using a predetermined arithmetic expression and outputs them to a signal processor. The signal processor carries out a filtering process on a weighing signal using the filter coefficients. The arithmetic expression includes a spectrum parameter specifying a band position of an attenuation band where attenuation must be locally enhanced. A user can input a value of the parameter via a data entry part. Each band is specified by the spectrum parameter not as the lowest limit value of a normalized angular frequency, but as the amount of deviation (the amount of displacement) from its center frequency.

Abstract: A filtering technique which makes it possible to easily and appropriately eliminate a noise without increasing a scale of a circuit necessary for a filtering process even if a noise frequency is liable to be changed is provided. A filter coefficient calculator (6) of a weight measurement apparatus calculates filter coefficients using a predetermined arithmetic expression and outputs them to a signal processor (5). The signal processor (5) carries out a filtering process on a weighing signal (Ds) using the filter coefficients. The arithmetic expression includes a parameter specifying a band position of an attenuation band where attenuation must be locally enhanced. A user can input a value of the parameter via a data entry part (7). In this manner, the filter coefficients can be changed by using a parameter specifying the band position of the attenuation band which is physical and thus easy to grasp.

Abstract: Disclosed is a process for producing fine particles of crosslinked urea-formaldehyde polymer which comprises the steps of synthesizing a precondensate of urea and formaldehyde, allowing the precondensate to react by the addition of an aqueous solution of an acid catalyst, and then neutralizing the reaction mixture, characterized in that the filtrate obtained in the filtration step for separating the polymer particles is recycled to the reaction system at the step of synthesizing a precondensate of urea and formaldehyde and/or the step of allowing the precondensate to react by the addition of an aqueous solution of an acid catalyst and in that the precondensate is obtained by reaction 1 mole of urea with 1.4 to 1.9 moles of formaldehyde at a pH of 6 to 10 and a temperature of 10 to 95.degree. C.