• Title/Summary/Keyword: sine wave generator

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Jamming Signal Rejection Algorithm for Uplink of Unmanned Aerial System (무인항공시스템의 상향링크를 위한 재밍신호 제거기법)

  • Lee, Yong-Wook
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.2
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    • pp.182-188
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    • 2018
  • In order to increase the robustness of the uplink for UAS(Unmanned Aerial System), we propose a jamming signal rejection algorithm. In the UAS datalink system, DSSS (direct sequence spread spectrum) is used to reduce the radio noise or jamming signal. In general, jamming signals below the spreading gain are recoverable but the signals beyond the spreading gain can not be recovered. In this paper, these jamming signals beyond spreading gain are detected using the threshold detector in the spectrum area then, generate the estimated signals from the sine wave generator. Finally, we obtain the desired signal to remove jamming signals from the received signals. The proposed scheme can eliminate jamming signals while minimizing the hardware complexity and the original signal loss.

The implementation of modular respiratory system for patient monitoring (환자감시를 위한 모듈형 호흡 시스템의 구현)

  • 박종억;김영길
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2001.05a
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    • pp.503-506
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    • 2001
  • There are four factors for patient monitoring : electrocardiography, blood pressure, temperature and respiration. While there are a lot of studies of E.C.C (electro-cardiography) monitoring system in the world, the studies of Respiratory system are not enough and leave much to be desired in the country. In this paper, we developed a respiratory system with the electrical impedance change of the lungs depending on the breath. Using the same electrode, we can monitor E.C.C and Respiration simultaneously, so we can monitor a patient's no-breathing state due to the central nerve paralysis in the emergency room easily. In this monitoring system, the analog part was made separated from the digital part for reducing power source noise and protecting patient from electric shock. The analog part consists of the several parts a high-frequency sine-wave generator, all amplifier for amplifying any impedance change signal, an analog processing part for rectifying and filtering. And the digital parts consists of three parts an AD convertor for converting analog signal to digital signal, digital filter, and a digital part for digital signal processing. This system's merits are using the same electrode with E.C.C and developing the multiple patient monitoring system easily.

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Measurement of Electrical Conductivity of Glass Melter at High Temperature (유리 용융물의 고온에서 전기 전도도 측정)

  • Kim, Taesam;Kil, Daesup;Jung, Hunsaeng;Kang, Eunhee;Yoon, Soksung
    • Analytical Science and Technology
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    • v.13 no.6
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    • pp.775-780
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    • 2000
  • The electrical conductivity of glass melter at high temperature has been measured. The conductivity is an important physical property for the research and the manufacturing process of glass. Because high temperature is an inconvenient situation to measure the conductivity of glass melter, we have made a platinum crucible and electrode and have measured the conductivity at high temperature. KCl solution, of which concentration is adjusted to the conductivity of glass melter, is used to get parameters of the conductivity cell. A measuring circuit is composed with an AC 1 kHz sine wave generator and an operational amplifier. The cell constants are determined from the measured voltages and the equivalent conductances of KCl solution. Various cells are tested to find a suitable shape for high temperature experiment. The results are compared by cell size, electrode depth, and cell configuration. The conductivity of the borosilicate melter is $0.053{\Omega}^{-1}cm^{-1}$ at $1,450^{\circ}C$.

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Preparation and Optoelectric Characteristics of Low Power Consumption Type AC Powder EL Devices with Dielectrics and Rear Contact (유전재료와 후면전극에 따른 저전력 소비형 AC Powder EL 소자 제조 및 광전기적 특성)

  • Lee, Kang-Ryeol;Park, Sung
    • Journal of the Korean Ceramic Society
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    • v.39 no.2
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    • pp.120-125
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    • 2002
  • AC powder EL devices were fabricated by screen printing method with the dielectric materials in insulating layer and the electrical resistivity of rear electrode. Brightness and current density were measured at voltage range of 50∼300 $V_{rms}$ to estimate optoelectrical properties of AC powder EL devices, respectively. Frequency generator was used as system producing frequency and voltage of a sine wave. Brightness and current density were measured by luminometer and multimeter. Also, dielectric constant for dielectric layer was measured by impedance analyser after preparing thick film. Dielectric constant was improved with amount of $TiO_2$ to $BaTiO_3$ powder. By applying such a process to dielectric layer of low cost AC powder EL device, brightness was improved to 50 cd/$m^2$ at similar current density. Dielectric constant $BaTiO_3$ powder by solution combustion process is better than commercial $BaTiO_3$ powder. By applying to that of low power consumption AC powder EL device, brightness was improved to 85 cd/$m^2$. Brightness of AC powder EL device was relatively decreased by control of electrical resistivity of rear electrode, current density was also decreased.

Effects of Organic Binder and Film Thickness on Optoelectrical Properties of AC Powder EL Devices Prepared by Screen Printing Method for LCD Backlight Applications (LCD 백라이트를 위해 스크린 프린팅법으로 제조된 AC Powder EL 소자의 유기결합제와 막두께가 광전기적 성질에 미치는 영향)

  • Lee, Kang-Ryeol;Park, Sung
    • Journal of the Korean Ceramic Society
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    • v.38 no.12
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    • pp.1085-1092
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    • 2001
  • The high efficient AC powder EL devices classified by low cost and low power consumption type fabricated using screen printing method with film thickness and organic binder. Brightness and current density were measured at frequency range of 400Hz∼1kHz and voltage range of 50∼300V$\_$rms/ to estimate optoelectrical properties of AC powder EL devices, respectively. Frequency generator was used as system producing frequency and voltage of a sine wave. Also brightness and current density were measured by luminometer and multimeter. In the case of low cost type AC powder EL device, brightness and current density were about 43 cd/m$^2$and 20$\mu$A/cm$^2$when the thickness of phosphor and dielectric layer was 45∼50$\mu$m under no addition of plasticizer respectively. In the case of low power consumption type AC powder EL device, brightness and current density were about 74 cd/m$^2$and 30∼40$\mu$A/cm$^2$when the thickness of phosphor and dielectric layer was 45∼50$\mu$m and 15∼20$\mu$m under addition of 15wt% plasticizer respectively. Also, AC powder EL device fabricated in this study showed absolutely excellent characteristics as the lifetime was longer than products of other company.

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