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The burst frequency modulation (FM) control mode is applied to an LLC resonant converter with multiplier in this study for enhanced efficiency and low voltage ripple at light load. This control mode provides an effective solution to high‐voltage power supply with wide‐range loads such as the traveling wave tube (TWT) power supply. Shortages in the LLC resonant converter with multiplier at light load are analyzed and a burst FM control strategy is proposed accordingly. The principle of the LLC resonant converter with multiplier under this control mode is then analyzed in detail. A ripple control strategy and zero voltage switching (ZVS) method are proposed, where the controller is implemented by digital signal processing (DSP). The prototype of a TWT power supply based on the burst FM control mode is completed accordingly. In the burst FM control mode applied in this study, ZVS is realized from light load to full load, and the efficiency at light load is improved by 7% comparing with conventional FM mode. The voltage ripple at light load is reduced by 5 V comparing with conventional burst mode. The experimental result indicates that the proposed method is feasible and effective. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

High-frequency Doppler (HFD) sounding is one of the major remote sensing techniques used for monitoring the ionosphere. Conventional systems for HFDs mainly utilize analog circuits. However, existing analog systems have become difficult to maintain as the number of people capable of working with analog circuits has declined. To solve this problem, we developed an alternate HFD receiver system based on digital signal processing. The software-defined radio (SDR) technique enables the receiver to be set up without the knowledge of analog circuit devices. This approach also downsizes the system and reduces costs. A highly stabilized radio system for both the transmitter and receiver is necessary for stable long-term observations of various phenomena in the ionosphere. The global positioning system disciplined oscillator with an accuracy of 10 - 11 compensates for the frequency stability required by the new receiving system. In the new system, four frequencies are received and signal-processed simultaneously. The dynamic range of the new system is wider (> 130 dB) than that of the conventional system used in HFD observations conducted by the University of Electro-Communications in Japan. The signal-to-noise ratio significantly improved by 20 dB. The new digital system enables radio waves to be received with much smaller amplitudes at four different frequencies. The new digital receivers have been installed at some of the stations in the HFD observation network in Japan and have already captured various ionospheric phenomena, including medium-scale traveling ionospheric disturbances and sudden commencement induced electric field fluctuations, which indicates the feasibility of SDR for actual ionospheric observations. The new digital receiver is simple, inexpensive, and small in size, which makes it easy to deploy new receiving stations in Japan and elsewhere. These advantages of the new system will help drive the construction of a wide HFD observation network. [ABSTRACT FROM AUTHOR]

This paper proposes a novel integrated solution for real‐time power quality (PQ) disturbance analysis. Traditionally, the recognitions are based on the feature extraction and are implemented offline or on the advanced reduced instruction set computer machine/digital signal processor platforms. In this paper, the optimized deep belief network (DBN) analyzes the PQ signals by learning knowledge from raw data of signals directly, which maximizes the features of original signals, and runs on an embedded parallel computing platform (EPCP). In simulation studies, eight types of common PQ disturbances are divided into 17 classes of data frame models according to the PQ disturbances that may occur during a fixed period of time. These samples of data frame models are utilized to train and optimize the DBNs on a central server. Compared with the existing classifiers, the simulation results demonstrate that the proposed approach has higher accuracy and stronger robustness. Then, the optimized DBN is sent to EPCP, and the previous DBN model is updated. The EPCPs are used to recognize the signals of PQ disturbances from a real time digital system (RTDS). The proposed integrated solution has excellent performance regarding accuracy but is time consuming. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

This paper describes the teaching and research of signal processing and communications systems that took place during the development of a real-time transceiver and radio channel testbed at Hokkaido University, Japan. Digital signal processing (DSP) concepts were taught and learnt during both the testbed system development and also the results gathering and analysis stages. The performance of a modern multiple antenna communications system is dependent on a number of key parameters, and the student interaction with such a real-time system can assist in the understanding of key but often abstract theoretical concepts. The communications algorithm and architecture overview on a signal processing board containing a Xilinx field programmable gate array (FPGA) and Analog Devices TigerSharc DSP is detailed. The lessons learned and potential uses of the testbed in both teaching and research are also described. [ABSTRACT FROM AUTHOR]

In Japan, the interwoven systems of communication, transport, and information and the commercially-industrially-culturally compressed spaces of the metro-poles, like Tokyo, have created super-density as new cultural form of the present. In this respect, the installation works by Seiko Mikami respond to quotidian experience with high density and lack of individual space. In her interactive installations, we are targeted by programmed multisensors and robotic devices, which invite us to engage in close encounter with the measuring and moving tools of the installation. In this human-machine-interrelationship, which is set out for multiple participants, we will also achieve a sense of each other via technology. The technological environment becomes a perceptual space, which instigates awareness and self-awareness of our own. [ABSTRACT FROM AUTHOR]

To clarify the relationship between earthquakes and electrical phenomena, signals of three parameters were observed continuously at Sennan in Akita Prefecture, Japan: ground acceleration (GAC), earth potential difference (EPD), and electrostatic field in the atmosphere (EFA). A large metal plate was used as an electrostatic antenna to observe EFA variation. For this paper, we used the digital natural observation (D-NOB) method as a signal processing technique and found clear EPD and EFA waveforms during seismic wave propagation. Our observation and examination results show that GAC causes EPD variation. Subsequently, the EPD variation induces EFA variation. [ABSTRACT FROM AUTHOR]

Recent work [Iverson et al. (2003) Cognition, 87, B47-57] has suggested that Japanese adults have difficulty learning English /r/ and /l/ because they are overly sensitive to acoustic cues that are not reliable for /r/-/l/ categorization (e.g., F2 frequency). This study investigated whether cue weightings are altered by auditory training, and compared the effectiveness of different training techniques. Separate groups of subjects received High Variability Phonetic Training (natural words from multiple talkers), and 3 techniques in which the natural recordings were altered via signal processing (All Enhancement, with F3 contrast maximized and closure duration lengthened; Perceptual Fading, with F3 enhancement reduced during training; and Secondary Cue Variability, with variation in F2 and durations increased during training). The results demonstrated that all of the training techniques improved /r/-/l/ identification by Japanese listeners, but there were no differences between the techniques. Training also altered the use of secondary acoustic cues; listeners became biased to identify stimuli as English /l/ when the cues made them similar to the Japanese /r/ category, and reduced their use of secondary acoustic cues for stimuli that were dissimilar to Japanese /r/. The results suggest that both category assimilation and perceptual interference affect English /r/ and /l/ acquisition. [ABSTRACT FROM AUTHOR]

This paper proposes a method for precisely estimating sinusoidal frequency using five samples. The estimation procedure is implemented by interpolating the impulse location between DFT results. Five samples are used because two complex components are available in the DFT results. However, an estimation method which uses four samples and is called Prony's approximation method is known in the literature. To derive interpolation formulas for six or more samples is more complex. In this paper, strict estimation formulas and their simplified versions arc deduced from the DFTs of five samples. The frequency estimation error is also discussed with a computer-simulated experiment which shows a I percent r.m.s. error at a signal-to-noise ratio of 30 dB. This method may be applicable for representing frequency in a direct binary form which can be processed by simple operations such as addition, exclusive-OR, and sign extractions form the calculated value. [ABSTRACT FROM AUTHOR]

This paper proposes a method of realizing an adaptive normalized ARMA lattice filter. This filter was proposed in a previous paper and can be realized with an arbitrary ARM A order and with all the lattice coefficients less than one. Furthermore, these coefficients are equal, so the structure is simplified. The adaptive realization method proposed in this paper retains these features. In addition, we perform spectral estimation of a time-varying signal with frequency weighting and model identification of an unknown input system. In our paper we describe an experiment with a real speech signal to prove that our algorithm can be used for frequency-weighted spectral estimation. The use of real data to perform spectral estimation has not been attempted in other references. [ABSTRACT FROM AUTHOR]

When metallic telecommunication lines carrying digital signals are laid adjacent to ac supply lines in an office or a house, then the noise generated by the ac supply lines is induced on the telecommunication lines and the quality of transmission may be degraded. To calculate the induced voltage generated directly between the cores of a telecommunication line requires accurate values of the coupling admittance or coupling impedance between the two lines corresponding to the cable construction and the problem becomes very complicated. This paper proposes a simple method of estimating the voltage induced between the cores of a telecommunication line when the telecommunication line is laid adjacent to an ac supply line. The amount of coupling from the primary circuit with an open-circuited terminal and with a short-circuited terminal to the secondary circuit is measured. Using this value, the characteristics of the induced voltage corresponding to an arbitrary value of terminal impedance of the primary or secondary circuit simply are estimated. The validity of the estimation method was confirmed by experiments. [ABSTRACT FROM AUTHOR]

This article introduces a series of articles related to papers presented at the 2003 Symposium on VLSI Circuits, which was held at the Rihga Royal Hotel, Kyoto, Japan during June 12-14, 2003, published in the April 2004 issue of the IEEE Journal of Solid-State Circuits. The 2003 Technical Program Committees of the Symposium selected 77 papers to be presented. These papers covered a vast scope of digital, analog, memory, signal processing, and wireless and wire-line communication circuits.