• Journal of Sensor Science and Technology
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• v.13 no.6
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• pp.417-423
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• 2004

In order to obtain wide-beam characteristics and variable resonant frequency of a ultrasonic transducer for the array source, an electrode of transverse mode piezoelectric vibrator is divided, and an electronic inductance is connected to the divided electrodes. The electronic inductance is made by GIC (General Impedance Converter) circuit. Because the GIC circuit is made of OP-Amps and other passive elements, the value of the inductance can be selected easily. As the results, the electronic inductance is variable in the range from 0.2 mH to 1.2 mH. Using the inductance, the resonance frequency of the transducer can be changed in the range from 73 kHz to 86 kHz. In the directivity of the transducer, it is confirmed that the beam width of the transducer is wider than $80^{\circ}$ at -3 dB in water.

• International Journal of Control, Automation, and Systems
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• v.6 no.5
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• pp.767-775
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• 2008

Methods used for exploring marine resources and spaces include positioning a probe under water and then recalling it after a specified time. Hydro-acoustic Releasers are commonly used for positioning and retrieving of such exploration equipment. The most important factor in this kind of system is the reliability for recalling the instruments. The frequently used ultrasonic signal detection method can detect ultrasonic signals using a fixed comparator, but because of increased rates of errors due to outside interferences, information is repetitively acquired. This study presents an effective ultrasonic signal detection algorithm using the characteristics of a resonance and adaptive comparator Combined with the FSK+ASK modulator. As a result, approximately 8.8% of ultrasonic wave communication errors caused by background noise and transmission losses were reduced for effectively detecting ultrasonic waves. Furthermore, the resonance circuit's quality factor was enhanced (Q = 120 to 160). As such, the bias voltage of the transistor (Vb= 3.3 to 6.8V) was increased thereby enhancing the frequency's selectivity.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.374-378
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• 2014

The piezoelectric materials convert from mechanical energy to electrical energy. The piezoelectric materials are used in various engineering applications such as piezoelectric ultrasonic actuators. Since the piezoelectric coupling characteristics of the actuator systems should be considered at the initial design stage, it is essential to analyze the piezoelectric coupling characteristics of the ultrasonic actuators. In this study, we analyzed the electromechanical characteristics of piezoelectric stacked actuator using the equivalent circuit model with modal mass stiffness parameters. It was compared the admittance of piezoelectric stack actuators with the analytical circuit model and the finite element model. Also, the coupling coefficient of piezoelectric stack actuator was discussed according to the number of stacks of actuators.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.783-785
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• 2002

In this paper, the driving characteristic for a ring type ultrasonic motor is described. For driving of ultrasonic motor, a two-phase parallel-resonant inverter was made. The driving circuit simulation results are compared with measured frequencis and amplitudes.

• The Journal of the Acoustical Society of Korea
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• v.16 no.3E
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• pp.37-43
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• 1997

A frequency-variable ultrasonic vibrator is designed, which is made of a multi-layered PZT vibrator with a conical horn. Transmission line equations for the conical horn are derived and analyzed using the equivalent circuit method in order to analyze the characteristics of the vibrator. The controllability of the driving characteristics by varying the electrical impedance is confirmed by the experimental results of the free admittance characteristics and the vibrational velocity distributions.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.100-102
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• 2002

In this paper the driving characteristic for a traveling-wave type ultrasonic motor is described. For driving of ultrasonic motor, a two-phase resonant inverter and Digital IC was made. The driving circuit simulation results are compared with measured frequencis and amplitudes.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.741-742
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• 2006

In this paper, we suggested a method for game operation tools by Ultrasonic sensor. Various ideas are necessary for the development that a game is industrial. I use a Ultrasonic sensor in this study and use a model case, and an operation is going to hold a case shooting play. Therefore, I showed a former circuit and a formula related to this.

• Journal of the Korea Society of Computer and Information
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• v.7 no.1
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• pp.80-87
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• 2002

In this papers, It was researched Automatic frequency detection which need using ultrasonic utmost effort. As far as ultrasonic Automatic frequency detection, It was analog method, In more dedicated field, to solve a limit. It was needed a new method detection instrument.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.409-412
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• 1996

Ultrasonic sensors are widely used in various applications due to advantages of low cost, simplicity in construction, mechanical robustness, and little environmental restriction in usage. But the main purposes of the noncontact sensing are rather narrowly confined within object detection and distance measurement. For the application of object recognition, ultrasonic sensors exhibit several shortcomings of poor directionality which results in low spatial resolution of objects, and specularity which gives frequent erroneous range readings. To resolve these problems in object recognition, an array of the sensor has been used. To improve the spatial resolution, more number of sensors are used in essence throughout the various devices of the sensor arrays. Under the disguise of a fixed number of the sensors, the array can be shifted mechanically in several steps. In this paper we propose a practical sensor resolution enhancement method using an electronic circuit accompanying the sensor array. The circuit changes the transmitter output voltage in several steps. Using the known sensor characteristics, a set of different return echo signals provide enhanced spatial resolution. The improvement is obtained with neither the cost of the increased number of the sensors nor extra mechanical devices.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.2
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• pp.46-51
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• 2000

The generation of the intensive ultrasonic waves depend mainly on the energy conversion efficiency depending on high frequency oscillation of the generator and the control performance of stable output depending on load variation, respectively. In this dissertation, a new configuration of ultrasonic generator is specially proposed and designed for improving both efficiency and stability. The generating frequency is turned by a PLL. which is controlled through the detection on phase difference between outputs and currents of the loads and the output amplitude of MOSFET, Q1 are controlled by their products through the multiplier, which results in the control of the amplitude of voltage controlled oscillation. And finally, the proposed and designed ultrasonic generator is composed by the combination of the function in mentioned above. the analysis results of the proposed circuit shows a good agreement between simulations and experiments.