Abstract: Provided are a multiplierless FIR digital filter and a method of designing the same, in which a filtering operation is performed by not multipliers needed as many as the number of tap depending on design requirement but a small addition/subtraction circuit using extracted information after analyzing the property of a given coefficient and extracting information required for design by only adding/subtracting operations. In the method of designing the multiplierless FIR digital filter, four tables are created to extract and store information needed for adding and subtracting operations to coefficients of design requirement, and an addition table is created to set a sixteen-multiple adding section of which a least upper bound is the maximum value of when the coefficient is represented into an integer by taking a decimal part of the coefficient, and to store values obtained by adding the input data input synchronizing with a clock frequency as a unit of sixteen sections.

Abstract: Provided is a method for converting a dimension of a vector. The vector dimension conversion method for vector quantization includes the steps of: extracting a specific parameter having a pitch period from an input speech signal and then generating a vector of a dimension that varies according to the pitch period; dividing an entire frequency domain of the generated vector of the variable dimension into at least two frequency domains; and converting the vector of the variable dimension into vectors of mutually different fixed dimensions according to the divided frequency domains. Thereby, not only an error due to the vector dimension conversion is suppressed but codebook memory required for the vector quantization is effectively reduced.