• The Journal of the Acoustical Society of Korea
• /
• v.36 no.1
• /
• pp.57-63
• /
• 2017

This paper presents an active acoustic-reflection control algorithm based on a single sensor. The proposed algorithm operates in a system comprising a single sensor located nearby the reflective surface and a control transducer mounted on the reflective surface. First, the incident and reflected acoustic signals are separated from the sensor signal, and a control signal is generated using the separated signals. For the signal separation, the proposed algorithm requires the response of the reflection path which is estimated from the acoustic response between an external sound source and the sensor. Finally, the control filter is adjusted using the FxLMS (Filtered-x Least Mean Square) algorithm. To verify the effectiveness of the proposed algorithm, it was implemented in real time using a DSP (Digital Signal Processing) board, and the experimental results obtained in one-dimensional air-acoustic environment show that the reflections of the 1 kHz burst can be reduced by 11.6 dB.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.2A
• /
• pp.129-136
• /
• 2005

A multiplier generator, VPM_Gen (Variable-Precision Multiplier Generator), which generates Verilog-HDL models of multiplier cores with user-defined bit-width specification, is described. The bit-widths of operands are parameterized in the range of $8-bit{\sim}32-bit$ with 1-bit step, and the product from multiplier core can be truncated in the range of $8-bit{\sim}64-bit$ with 2-bit step, resulting that the VPM_Gen can generate 3,455 multiplier cores. In the case of truncating multiplier output, by eliminating the circuits corresponding to the truncation part, the gate counts and power dissipation can be reduced by about 40% and 30%, respectively, compared with full-precision multiplier. As a result, an area-efficient and low-power multiplier core can be obtained. To minimize truncation error, an adaptive error-compensation method considering the number of truncation bits is employed. The multiplier cores generated by VPM_Gen have been verified using Xilinx FFGA board and logic analyzer.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.24 no.7
• /
• pp.737-747
• /
• 2013

A 3-D surveillance radar is a pulsed-doppler radar to provide various target information, such as range, doppler and angle by performing TWS. This paper introduces HW/SW architecture of radar signal processing board to process in real-time using high-speed multiple DSP(Digital Signal Processor) based on COTS. Moreover, we introduced a implemented algorithm consisted of clutter map creation/renewal, FIR(Finite Impulse Response) filter for rejection of zero velocity components, doppler filter, hybrid CFAR and finally presented computational burden of each algorithm by performing operational test using a beacon.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.7 no.1
• /
• pp.81-90
• /
• 2002

This paper presents an Implementation of digital high-performance position sensorless control system of Reluctance Synchronous Motor(RSM) drives with Direct Torque Control(DTC). The system consists of stator flux observer, speed and torque estimator, two digital hysteresis controllers, an optimal switching look-up table, Insulated Gate Bipolar Transistor(IGBT) voltage source inverter, and TMS320C31 DSP board. The stator flux observer Is based on the combined voltage and current model with stator flux feedback adaptive control of which inputs are current and voltage sensed on motor terminal for wide speed range. In order to prove the suggested sensorless control algorithm for industrial field application, we have some simulation and actual experiment at low and high speed range. The developed high-performance speed control by fully digital system are shown a good response characteristic of control results and high performance features using 1.0[kW] RSM having 2.57 reluctance ratio of $L_d/L_q$.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.10
• /
• pp.1858-1865
• /
• 2007

In this paper, we introduce the design and implementation of satellite IP modem. The designed satellite IP modem shows the performance of 0.2% overhead, BER=10-5 when Eb/No=6dB, frequency offset of 8KHz, data rate up to 1536Kbps, $F_{if}=140MHz$. The designed system is verified through software simulation and then implemented with MPC86x communication processor, TMS320C6416 DSP, and Altera FPGA. Since each hardware unit is implemented in daughter board for modularity, we can reduce the development time and easily improve the performance with using better processor. Linux is used for embedded OS because it shows better performance in IP manipulation multitask processing, and hardware control through device driver. The implemented system is tested and verified with channel simulator. Since the proposed IP modem shows small size and light weight, that can be used anywhere with easy if you need IP environment.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.1069-1077
• /
• 2008

The railway abrasion measurement system have to satisfy two conditions to increase the measurement accuracy as follows. The laser region which is projected on the rail have to be extracted without the geometrical distortion. The mapping of the acquired laser region data on the rail profile have to be processed exactly. But, the conventional railway abrasion measurement system is deeply effected by the foreign substance( dust, rainwater, and so on ) on the railway or the sensitive response characteristic of the laser to the external measurement circumstance, and then the measurement errors arise from above factors. When the laser region is projected on the rail extracts from the acquired image, the interference of the light with the same frequency as the laser system occurs the serious problems. In the process of the mapping between the railway profile and the extracted laser region, the measurement accuracy is very highly effected by the geometrical distortion and the abnormal variation. In this Paper, we propose the novel method to increase the accuracy of the railway abrasion measurement dramatically. we designed and manufactured the high precision and fast image processing board with DSP Core and FPGA to measure the railway abrasion. The image processing board has the capability that the image of 1024X1280 from camera can be processed with the speed of 480 frame/sec. And, we apply the image processing algorithm base on the wavelet to extract the laser region is projected on the rail exactly. Finally, we developed high precision railway abrasion measurement system with the error range less than +/-0.5mm by which 2D image data is covered 3D data and mapped on the rail profile using the camera model and the perspective transform.

• Journal of the Institute of Convergence Signal Processing
• /
• v.9 no.2
• /
• pp.141-145
• /
• 2008

When the current flows to parallel lines with different length, it is researched that the radiation is occured by the common-mode current radiates, and the small light weight antenna composed of dual elements by using the principle is proposed. However, there is a problem in production about this antenna because this liner antenna is structured by combining with wires. In this paper, we improved this liner antenna, and designed the plane antenna composed of dual elements with different length in the plane printed board to produce and to design easily. Furthermore, the antenna with the wide-band characteristic is also designed in the same board. The radiation pattern is similar to the dipole antenna on account of designing the triangular patch S, the notch and two tapers in patch S, the notch and two tapers in the antenna element. In result, it was able to design the antenna working wider band-width(the bandwidth ratio about 58%, $VSWR{\le}2$).

• The Transactions of the Korean Institute of Power Electronics
• /
• v.22 no.3
• /
• pp.240-248
• /
• 2017

This paper describes the development of a powertrain for a 20 kW experimental electric vehicle using a surface-mounted permanent magnet synchronous motor (SPMSM) and its application to a test vehicle. Two 10 kW SPMSMs are used in the powertrain, and two-level inverters are developed by using IGBTs to derive these motors. To control the SPMSM, a control board based on a TMS320F28335 DSP module, which has fast arithmetic function and floating point operator, is used. We develop a 100 V/40 A battery pack, which includes $32{\times}4$ LiFePO4 battery cells using commercial BMS. A commercial on-board charger with 220 V (AC) input and 100 V (DC) and 18 A output is used to charge the battery pack. The performance of the developed vehicle, such as acceleration availability, maximum speed, and maximum power, is estimated based on vehicle dynamics and verified through experiments.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1936-1939
• /
• 2004

This paper proposes streaming layer for personal robot's middleware. Under assumption that robot has open architecture, i.e. consists of modules created by different vendors and intercommunication between these modules is necessary, we have to consider that there are many different network interfaces. To make communication between modules possible it is necessary to develop new type of middleware. Such middleware has to support different platforms, i.e. OS, network interface, hardware, etc. In addition, it is necessary to implement effective interface between network and application in order to manage inter application communications and use network resources more effectively. Streaming layer is such interface that implements necessary functionality together with simplicity and portability. Streaming layer provides high level of abstraction and makes communication between distributed applications transparent as if are located in same module. With possibility of extension by user defined application interfaces it is suitable for distributed environments, i.e. module based architecture including small-embedded systems like as DSP board. To verify the proposed streaming layer structure it is implemented using C and tested.

• The Journal of the Acoustical Society of Korea
• /
• v.18 no.3
• /
• pp.79-87
• /
• 1999

In this paper, we reconstruct an algorithm of sound image control for real-time processing and implement a real-time system using digital signal processing board based on TMS320C40. The performance of real-time sound image control system was evaluated by a listening test. The results of the test showed that localized sound image can be perceived by headphone and speaker, and result of test by headphone was better than that of speaker. In the results of test of elevation perception, result of perception between left and right were better than those for differentiating between front and back, and the moving sound image was better than the fixed sound image.