• Journal of Advanced Marine Engineering and Technology
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• v.15 no.4
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• pp.54-69
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• 1991

This study deals with the position control of a hydraulic cylinder system operated by two port 3-way high speed solenoid valve in Pulse-Width-Modulation mode, instead of using conventional electro-hydraulic servovalve. Due to the complexity and the relatively poor reliability of the servovalve, an actuator using simpler and more study high speed solenoid valve will be presented. The high speed solenoid valve acts as converters of electronic pulse signal to hydraulic ones. It has been pointed out that there are practical problems to be solved in the PWM system, that is (1) accuracy of positioning control becomes considerably insufficient because the system is affected by on/off action of the solenoid valves, and (2) serious nonlinerality appears in the valve characteristics as a result of the switching behavior of the valves. As a method to overcome these defects, the differential PWM driving method of a hydraulic cylinder that improved the steady-state-error, flow rate nonlinearity in simple PWM, and the hydraulic hunting of dead time compensated-PWM driving is proposed in this study.

• Journal of the Korean Institute of Telematics and Electronics
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• v.6 no.3
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• pp.1-7
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• 1969

The Series RC load is connected with the word line in an attempt to select with high speed the information from the coincident current magnetie memory core. By taking the small time constant of the RC load, the cycle time of the output pulse is shortened by about 2 microseconds to 3 micro seconds. For this purpose, the analytical study are accomplished and the optimum circuit parameters are determined. Furthermore, the thermal problems occuring from the high speed switching of the magnetic memory core have been clarified.

• The Journal of the Acoustical Society of Korea
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• v.14 no.4
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• pp.5-11
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• 1995

In this paper, we design the new high-speed seek algorithm which can access the data of disk (in 3.5-inch optical disk drive). When seek the target track on optical disk in high-speed using the ref-T. E(Reference Tracking Error) and sample pulse signal, it's always possible high-speed seek without re-check and compensation for error by the ref_T. E and sample pulse signal. The performance test result is represented as follow ; it is satify the average seek time of 28mses.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.45-52
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• 2009

This study is related to the realization of high speed address driving method for Full-HD PDP. The new self-priming addressing(SPA) driving scheme was proposed to improve an address discharge time lag, which utilizes the priming effect maintaining the priming discharge during an address period. In this study, the basic characteristics of the priming ramp discharge were investigated and optimize the reset pulse and priming pulse. It is noted that the address discharge time lag is significantly improved from 1.2[${\mu}s$] to 0.8[${\mu}s$] when the slope of the priming ramp pulse is below 0.1[$V/{\mu}s$].

• Laser Solutions
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• v.17 no.3
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• pp.15-18
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• 2014

In this paper, we studied a machining method using a diffractive beam splitter (DBS) and multi- pulse repeated radiation for breathable film. We fabricated micro-grooves on polypropylene (PP) films using multi-pulse radiation and one-shot radiation (radiating pulses at once) and a DBS. In the result, width and depth of the PP film using multi-pulse repeated radiation were more precisely controllable. Therefore, this method can be applicable to in manufacturing breathable film precisely at a high speed.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.330-333
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• 2000

With the recent development of the ultrahigh-speed optical time division multiplexed system, high-repetition rate optical-pulse stream generation is necessary. This is different from conventional approaches, which use fiber or integrated waveguide delay line circuits. The high-repetition-rate optical-pulse multiplication phenomenon occurs when the optical pulse's spectral width is greater than the transfer bandwidth of the coupler used. From the analysis, the output repetition rate can be controlled by using fiber couplers with different equivalent transfer bandwidths. The pulse seperation spacing is controlled by number of cascaded coupler in optical loop mirror coupler scheme.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.23-28
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• 2005

An airborne radar is an essential aviation electronic system of the helicopter to perform various missions in all-weather environments. This paper presents the results of the design and implementation of the airborne pulse doppler radar signal processor using high multi-DSP for the multi-function radar capability such as short-range, midium-range, and long-range depending on the mission of the vehicle. Particularly, the radar signal processor is developed using two DSP boards in parallel for the various radar signal processing algorithm. The key algorithms include LFM chirp waveform-based pulse compression, MTI clutter filter, MTD processor, adaptive CFAR, and clutter map. Especially airborne moving clutter Doppler spectrum compensation algorithm such as TACCAR is implemented for the multi-mode airborne radar system. The test results shows the good Doppler spectral separation for the clutter and the moving target in the flight test environment using helicopter.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.337-340
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• 2002

In data transmission at the digital satellite broadcasting systems, the delay and spread are caused whit receiving original signals from the transmitter in the receiver. So, there are some problems in data fast transmission. Also, transmitted signals ate received in stale of the combination of transmission delay and noise of channel. The affect of channel noise is reduced when increasing transmission power, but as signal interference due to the transmission delay and spread of channel increase in proportion to the transmission power, there is a problem in spite of increasing the transmission power. And there is the problem to add ISI(inter symbol interference) because the property of the channel is limo-varying due to relative moving in the transceiver Therefore, in this paper, a pulse shaping filter for the high-speed service in digital satellite broadcasting systems was designed and reduced the ISI.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.6
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• pp.816-820
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• 1990

A Tx modulator of the AMPS cellular wireless communication has been implemented using the PLL synthesizer, of which is modified for multiple frequency output capability. The frequency range is in 825-845 MHz with the 666 channels of 30KHz channel spacing and its switching time is less than 40 msec. The purpose of this paper is to develope the PLL frequency synthesizer with the high speed pulse swallow prescaler in order to save power consumption and cost. The PLL frequency synthesizer is studied in this paper to apply the cellular communication modulator.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2467-2469
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• 1998

We examine the performance of high-speed non-directed infrared links using pulse-position modulation (PPM) with trellis-coded modulation (TCM) to mitigate the effects of multipath-induced intersymbol interference(ISI) on such links. Using the measured characteristics of multipath indoor infrared channels, we calculate BER curves and ISI power penalties for maximum-likelihood sequence detection of 8-PPM links using rate-2/3 trellis codes operation at 10 and 30Mb/s. Our results indicate that the suggested decoder of PPM with TCM is a very promising decoder on high-speed non-directed infrared channels.