Journal of Signal Processing
Online ISSN : 1880-1013
Print ISSN : 1342-6230
Volume 18 , Issue 3
Showing 1-5 articles out of 5 articles from the selected issue
  • Sukanya Praesomboon, Kobchai Dejhan, Surapun Yimman
    2014 Volume 18 Issue 3 Pages 121-134
    Published: May 25, 2014
    Released: May 25, 2014
    JOURNALS FREE ACCESS
    This paper proposes the reduction effect of reconstruction filter for digital signal processing system. It is well known that the reconstruction filter limits the bandwidth of output signal processing and the output signal is staircase form or has high frequency components. For effect reduction we use the nonrecursive system which corresponds with the inverse system function of the reconstruction filter. The initial step starts with the analog system function of the reconstruction filter and is converted to a discrete-time system using the approximation of derivative technique and inverse system. This inverse discrete-time system function is a nonrecursive system to compensate the reduction effect of the reconstruction filter implemented by using the software. For hardware experiments, we use TMS320C31 digital signal processor, D/A, PIC-32 microcontroller, PWM analog output. The experimental results of the proposed principle show that it can be used to compensate the bandwidth and reduce the total harmonic distortion (THD) of high frequency signal. In addition, this experiment shows that the nonrecursive system for compensation uses only first-order system and it does not utilizes any more processor. Furthermore, it is able to increase the performance. The applications are such as digital filtering, digital control and audio processing. They can be done with high accuracy using the proposed principle.
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  • Kuniaki Kawabata, Hitoshi Aonuma, Satoru Takahashi, Koh Hosoda, Jianru ...
    2014 Volume 18 Issue 3 Pages 135-141
    Published: May 25, 2014
    Released: May 25, 2014
    JOURNALS FREE ACCESS
    This paper describes an image-based agent's pose estimation method for supporting experiments on cricket-micro mobile robot interactions. Crickets modify their behavior selection tendency as a result of experience and the context based on the interaction with other crickets. Such a behavior selection mechanism with a tiny brain is a typical example to understand the adaptability of animals. Behavior observations in such interaction experiment sometime impose a burden on the experimenter. Therefore, in our previous works, we reported the development of a visual tracking method for two agents. However, it only tracked the positions of the agents. In this paper, utilizing our method, we also develop an image-processing algorithm for simultaneous pose estimation based on visual features related to the head part of each agent. We conducted estimation experiments based on video recordings of cricket-robot interactions and confirmed that our proposed method could estimate the pose of both agents. This method will help to efficiently analyze behavioral data during interaction experiments.
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  • Nobuo Nagai, Jie Ren, Takashi Yahagi
    2014 Volume 18 Issue 3 Pages 143-148
    Published: May 25, 2014
    Released: May 25, 2014
    JOURNALS FREE ACCESS
    For the frequency of a unit element whose phase is nπ, the unit element has eigen oscillation. By a parallel connection of two unit elements, we can obtain a loop circuit. Since we obtain image phase of the loop circuit by image parameter theory, we can show that the loop circuit has eigen oscillation.
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  • 2014 Volume 18 Issue 3 Pages 149-150
    Published: 2014
    Released: May 25, 2014
    JOURNALS FREE ACCESS
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  • 2014 Volume 18 Issue 3 Pages 151-152
    Published: 2014
    Released: May 25, 2014
    JOURNALS FREE ACCESS
    Download PDF (184K)
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