• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.36S no.9
• /
• pp.103-112
• /
• 1999

In this paper, a speaker-independent isolated world recognition system for a car navigation system is implemented using a general digital signal processor. This paper presents a method combining SNR normalization with RAS as a noise processing method. The semi-continuous hidden markov model is adopted and TMS320C31 is used in implementing the real-time system. Recognition word set is composed of 69 command words for a car navigation system. Experimental results showed that the recognition performance has a maximum of 93.62% in case of a combination of SNR normalization and spectral subtraction, and the performance improvement rate of the system is 3.69%, Presented noise processing method showed good speech recognition performance in 5dB SNR in car environment.

• Journal of IKEEE
• /
• v.18 no.2
• /
• pp.282-290
• /
• 2014

This paper presents the design of embedded electrical power control unit for Personal Electrical Vehicle(PEV). The embedded unit is designed using PIC18F8720 processor, 16Mb flash ROM, 32Mb SDRAM and signal condition circuits. The proposed PEV consists of 4KW in-wheel Brushless DC Motor(BLDCM), 3 phase voltage source inverter with the $180^{\circ}$ conduction space vector PWM method, PID speed controller and the embedded control unit. The PEV has mechanical manufacture of inverse 3 wheel system, which is applied by the in-wheel BLDCM and steering mechanism with tilting function. Also, the performances of the proposed embedded electrical power control unit are verified through the lab experiment and road driving test of PEV.

• Journal of IKEEE
• /
• v.24 no.1
• /
• pp.178-185
• /
• 2020

This paper proposes precise time synchronization-based synchronized sampling structure applied HW/SW platform for LAN-based protection of future digital substations. The integrated software of the proposed platform includes IEC 61850 protocol, IEEE 1588 precision time protocol and synchronized sampling structure. The proposed platform expected to provide a basis of an application of future distributed sensing data-based protection and control methods by providing synchronized measurement among IEDs. The implementation of the proposed HW/SW platform technique was performed using TMDXIDK572 multi-core/multi-processor evaluation module and its time synchronization performance and synchronized sampling function were confirmed through the performance tests.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.2
• /
• pp.303-308
• /
• 2001

An objection of this study is to develop a high stable measuring circuits and a analytic system for radioactive pulses. The proposed system consists of a pulse detection units for neutrons and gamma-rays a programmable high voltage supply unit and a digital signal processor. The programmable high voltage supply unit designed can generate DC voltage up to 1,500 V at 5 V input and have a series voltage regulator to maintain the output voltage constantly, resulting in less than 1.63% of voltage regulation. The pulse detection parts consists of an active integrator, a pole-zero circuit, and a 3-stage amplifier of 60 dB, and its frequency bandwidth is from 37 Hz to 300 kHzAlso, pulse height distribution in accordance with pulse counts is important data in analyzing radioactive pulses. In this study, A/D convertor (12bit, 100ms) and DSP (TMS320C31-60) are used to analyze the pulse height, and the analytic system is designed to be operated in PC-base.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.12
• /
• pp.3029-3034
• /
• 2014

The paper describes the scleral diagnostic system implementation for human eyes by using the scleral color code and vessels sign pattern code generations. The system is based on the high performance DSP image signal processor, programmable gain control for preprocessing and RISC SD frames storage. RGB image signals are optimized by PGC, the edge image is detected form the gray image converted. The processing algorithms are executed by scleral color code generation and scleral vessels sign pattern code creation for discriminating and matching. The scleral symptomatic color code is generated by YCbCr values at memory map tolerated and the vessel sign pattern code is created by digitizing the 24 clock and 13 ring zones, overlay matching and tolerances. The experimental results for performance are that the system runs 40ms, and the color and pattern for diagnostic errors are around 20% and 24% on average. The system and technique enable a scleral diagnosis with subdividing the patterns and patient database.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.15 no.3
• /
• pp.188-198
• /
• 2010

Recently, as the demand of the environmental-friendly energy storage system such as an electric double-layer condenser increases, that of the bidirectional charger/discharger for the systems also increases. However, when charging/discharging mode-change occurs, the charger/discharger employing a bi-directional DC-DC converter with a commercialized analog controller has a complex circuit scheme, and a poor transient response. On the other hand, if a single digital controller is used for the bi-directional mode, the system performances can be improved by application of an advanced power-processing algorithm. In the paper, an environmental-friendly power storage systems including an Electric Double Layer Capacitor(EDLC) banks were developed with a bi-directional buck-boost converter and a digital signal processor (TMS320F28335). A simulation test-bed was realized and tested by MATLAB Simulink, and the hardware experiment was performed which shows that the dynamic response was improved such as the simulation results.

• The Journal of the Acoustical Society of Korea
• /
• v.20 no.1
• /
• pp.56-61
• /
• 2001

This paper presents the real-time implementation of an AMR (Adaptive Multi Rate) vocoder which is included in the asynchronous International Mobile Telecommunication (IMT)-2000 mobile ASIC. The implemented AMR vocoder is a multi-rate coder with 8 modes operating at bit rates from 12.2kbps down to 4.75kbps. Not only the encoder and the decoder as basic functions of the vocoder are implemented, but VAD (Voice Activity Detection), SCR (Source Controlled Rate) operation and frame structuring blocks for the system interface are also implemented in this vocoder. The DSP for AMR vocoder implementation is a 16bit fixed-point DSP which is based on the TeakLite core and consists of memory block, serial interface block, register files for the parallel interface with CPU, and interrupt control logic. Through the implementation, we reduce the maximum operating complexity to 24MIPS by efficiently managing the memory structure. The AMR vocoder is verified throughout all the test vectors provided by 3GPP, and stable operation in the real-time testing board is also proved.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.27 no.10
• /
• pp.900-908
• /
• 2016

In this paper, we have studied the tracking system with a single channel monopulse receiver that has a comparative advantage of costs, size, weight, and power consumption over the general 3-channel monopulse receivers. After the single channel monopulse system was composed of an antenna, a monopulse receiver, a servo unit, a RF signal processor unit and a power supply unit, we analyzed the basic tracking performance of the tracking error angle and the pointing loss. And we proved the tracking performance to a moving target in the outdoor environment. On the Analysis of the tracking test results, the single channel monopulse system shows a equal or higher performance over the general 3-channel monopulse system and also has advantages of the system implementation. Also, it is concluded that this study is useful to apply a single channel monopulse receiver with benefits of production price and miniaturization when the monopulse tracking systems will be developed in the future.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.11 no.6
• /
• pp.64-73
• /
• 1997

RPWM(Random Pulse Width Modulation) techniques have been attracting an interest as an excellent reduction method of acoustic noise on the inverter drive system. Using randomly changed switching fre-quency of the inverter, the power spectrum of the electromagnetic acoustic noise can be spread out into the wide-band area. The wide band noise is much more comfortable and less annoying than the narrow-band one. This paper describes an implementationof the triangular carrier frequency modultde RPWM inverter drive system The poweer soedtrum of the noise emittde from the induction motro was measured in the anechoic chamber. The analysis of the sources for the acoustic noise and the effects of the noise reduction are confirmed by the ceasured dpectra of the noise. Real-time RPWM along with the speed control was achieved by high speed DSP(Digital Signal Processor ) TmS320C31, By changing the center frequency and the bandwidth of the carrier, theis real-time RPWM scheme can be used as an efficient switching frequency band acoustic noise reduction method for the inverter system with variant load conditions.

• Journal of Power Electronics
• /
• v.15 no.1
• /
• pp.190-201
• /
• 2015

This paper uses the switching function approach to present a simple state model of the Vienna-type rectifier. The approach introduces the relationship between the DC-link neutral point voltage and the AC side phase currents. A novel direct power control (DPC) strategy, which is based on the sliding mode control (SMC) for Vienna I rectifiers, is developed using the proposed power model in the stationary ${\alpha}-{\beta}$ reference frames. The SMC-based DPC methodology directly regulates instantaneous active and reactive powers without transforming to a synchronous rotating coordinate reference frame or a tracking phase angle of grid voltage. Moreover, the required rectifier control voltages are directly calculated by utilizing the non-linear SMC scheme. Theoretically, active and reactive power flows are controlled without ripple or cross coupling. Furthermore, the fixed-switching frequency is obtained by employing the simplified space vector modulation (SVM). SVM solves the complicated designing problem of the AC harmonic filter. The simplified SVM is based on the simplification of the space vector diagram of a three-level converter into that of a two-level converter. The dwelling time calculation and switching sequence selection are easily implemented like those in the conventional two-level rectifier. Replacing the current control loops with power control loops simplifies the system design and enhances the transient performance. The simulation models in MATLAB/Simulink and the digital signal processor-controlled 1.5 kW Vienna-type rectifier are used to verify the fast responses and robustness of the proposed control scheme.