Masayuki Kawamata

Learn More
—This paper proposes a new method for online secondary path modeling in active noise control systems. The existing methods for active noise control systems with online secondary path modeling consist of three adaptive filters. The main feature of the proposed method is that it uses only two adaptive filters. In the proposed method, the modified-FxLMS(More)
— This paper proposes a new method for online secondary path modeling in active noise control (ANC) systems. The proposed method is a modified version of the basic method, proposed by Eriksson et. al. The objective is to realize improved performance at a reasonable computational cost. In the proposed method, the control filter is adapted by using same error(More)
SUMMARY In this paper, we propose a novel bicubic method for digital image interpolation. Since the conventional bicubic method does not consider image local features, the interpolated images obtained by the conventional bicubic method often have a blurring problem. In this paper, the proposed bicubic method adopts both the local asymmetry features and the(More)
This paper proposes a simple method of realization of center-frequency adaptive filters for high-accuracy detection of band-pass signals immersed in a broadband signal. Our method extends the conventional method proposed by Kumar and Pal. While the conventional center-frequency adaptive filters were mathematically difficult to describe in the case of high(More)
There has been a constant interest in the design and implementation of digital filters with variable characteristics for different applications. In this article an attempt is made to review and systematize all known structures and methods of design of such filters. First the basic theory of the variable digital filters is introduced. Then FIR and IIR(More)
SUMMARY This paper proposes a closed form solution to L 2-sensitivity minimization of second-order state-space digital filters subject to L 2-scaling constraints. The proposed approach reduces the constrained optimization problem to an unconstrained optimization problem by appropriate variable transformation. Furthermore, restricting ourselves to the case(More)
—This letter proposes a synthesis method for low coefficient sensitivity second-order IIR digital filter structures using Genetic Programming with Automatically Defined Functions (GP-ADF). In this letter, digital filter structures are represented as S-expressions with subroutines. It is easy to generate syntactically valid S-expressions and perform the(More)
— This paper proposes a novel approach to L2-sensitivity minimization problem of state-space digital filters subject to L2-scaling constraints. The proposed approach reduces the constrained optimization problem to an unconstrained optimization problem by appropriate variable transformation. As a result, iterative algorithms for the L2-sensitivity(More)
—This brief proposes a systematic approach to synthesis of limit cycle free state-space digital filters with minimum 2-sensitivity. We synthesize the minimum 2-sensitivity realization adopting the balanced realization as an initial realization. The coordinate transformation matrix which transforms the balanced realization into the minimum 2-sensitivity(More)
— This paper proposes a new expression of frequency transformation for linear continuous-time state-space systems. The proposed frequency transformation preserves the controlla-bility Gramian and the observability Gramian of prototype state-space systems, and thus allows us to easily realize various kinds of state-space systems keeping the same realization(More)