• Journal of Positioning, Navigation, and Timing
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• v.4 no.1
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• pp.25-31
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• 2015

In this paper, we described the timing-offset comparison results between various daily jump compensation methods for GPS carrier phase (CP) measurement data. For the performance comparison, we used about 70 days GPS measurement data obtained from two GPS geodetic receivers which share the reference 1 PPS and RF signals and closely located in each other within a few meters. From the experiment results, the followings were observed. First, daily jumps existed in CP measurements depend on not only the environment but also the receiver which will make a full compensation be very hard or impossible. Second, clock bias can be occurred in the case of using a simple compensation with accumulation of daily jumps but it could be used in a short-period frequency comparison campaign (less than about 7 days) despite of its drawback.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.5
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• pp.63-68
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• 1998

The absolute pressure sensor using SDB wafer has been fabricated. the structure of the sensor consists of two wheatstone bridges and a diaphragm. One of the two wheatstone bridges is located on the edge of diaphragm, and the other is located on the center of diaphragm. The diaphragm cavity is sealted in vacuum (~10$^{5}$ Torr) to reduce the effect of temperature due to the vapor in the cavity on the sensitivity of pressure sensor. This is the minor method of temperature compensation method. In this experiment the main compensation method is to use the difference of the two bridge offset voltages. The drift of offset voltage with temperature is reduced by using this method so that temperature charcteristics is improved. In this method the temperature effect in the range of 22~100.deg. C was compensated over 80%.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.274-276
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• 1995

The non-ideal elements inherent in all categories of AC drives have a significant influence on the performance of speed control. For the high performance of speed control, these non-ideal elements must be considered. This paper discusses the side effects of non-ideal elements such as the offset current of A/D converter, asymmetry of motor and so on and proposes simple compensation methods which are also applicable to any kinds of the motor drive systems. In the experimental results, it is observed that the proposed compensation methods improve the performance of speed control.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.5
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• pp.387-391
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• 2011

A uncooled infrared ray sensor used in an infrared thermal imaging detector has many advantages. But because the uncooled infrared ray sensor is made by MEMS (micro-electro-mechanical system) process variation of offset is large. In this paper, to solve process variation of offset a ROIC for uncooled infrared ray sensor that has process variation of offset compensation technique using differential delta sampling and reference signal compensation circuit was proposed. As a result of simulation that uses the proposed ROIC, it was possible to acquire compensated output characteristics without process variation of offsets.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5A
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• pp.441-449
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• 2011

Sample timing offset (STO) and carrier frequency offset (CFO) are caused by inter-symbol interference (ISI), inter-carrier interference (ICI) and phase error in orthogonal frequency division multiplexing (OFDM) system. OFDM characteristic is sensitive about STO and CFO. So when ICI occurs, compensation is hard and complex equalizer is needed. In this paper, we propose an effective correction method using feedback process with pilot and synchronization symbol. After feedback with estimated value in frequency domain, STO and CFO are corrected by control sample & and holder and oscillator. As a result of simulation, we confirm that STO and CFO can be corrected without equalizer through feedback.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.1
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• pp.39-46
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• 2017

In this paper, we propose an integer frequency offset estimation and compensation method based on PLC preamble correlation in DOCSIS 3.1 Downstream system. The proposed method determines the PLC preamble subcarrier location recovered from PLC data and the one obtained from PLC preamble correlation. We showed the performance of PLC preamble detection in the received signal through the maximum value detection of PLC preamble correlation. Thus we can estimate and compensate for the integer frequency offset by computing the difference of PLC subcarrier locations.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.915-918
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• 2003

본 논문에서는 높은 슬루율을 가지고 전압편차 (offset)보상 기능을 가지면서도 전력소모가 적은 고계조 TFT-LCD 데이터 드라이버 구동용 단일이득 연산증폭기(unit gain op-amp)의 바이어스 회로 및 구동 방법을 제안하였다. 제안한 단일이득 연산증폭기는 일반적으로 사용되고 있는 전압편차 보상기능을 가진 단일이득 연산증폭기에 adaptive bias기능을 추가한 것으로써, 기존 구조에 비해 50%이상의 소비 전력 절감 효율을 보였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.323-326
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• 2004

In this study, the inspection path which is considered to free collision is generated by offset surface. When the inspection is executed, the consideration of machine dynamic error increases a precision. Dynamic error is measured on CNC machine bed changing of weight work price. Offset surface is safety space about collision. Because the danger of probe-collision is excluded in Offset surface, it is possible to rapid feed of probe and reduced inspection time. The Program which is possible to simulate using CAIP and is confirmed through actual experiment.

• Journal of Korea Technology Innovation Society
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• v.14 no.4
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• pp.860-888
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• 2011

Offset is a peculiar trade form, the compensation of importing the weapon system, accompanied by the international weapon system contract. Korea has been applying offset to defense acquisition program for fostering the domestic defense industry and improving defense R&D ability since Korean offset policy was built up in 1983. However, there are not enough evidences for benefits of offset and it is rather believed that the performance management system of offset is not thoroughgoing enough because of lack of the systematic policy. It is essential to develop the well-organized performance management system in order to maximize outcomes from application of technology obtained by offset. The main objective of this paper is to propose key performance index that is practically useful to manage offset performance systematically and maximize outcomes of offset.

• Journal of Power Electronics
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• v.5 no.2
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• pp.151-159
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• 2005

The errors generated from current measurement paths are inevitable, and they can be divided into two categories: offset error and scaling error. The current data including these errors cause periodic speed ripples which are one and two times the stator electrical frequency respectively. Since these undesirable ripples bring about harmful influences to motor driving systems, a compensation algorithm must be introduced to the control algorithm of the motor drive. In this paper, a new compensation algorithm is proposed. The signal of the integrator output of the d-axis current regulator is chosen and processed to compensate for the current measurement errors. Usually the d-axis current command is zero or constant to acquire the maximum torque or unity power factor in the ac drive system, and the output of the d-axis current regulator is nearly zero or constant as well. If the stator currents include the offset and scaling errors, the respective motor speed produces a ripple related to one and two times the stator electrical frequency, and the signal of the integrator output of the d-axis current regulator also produces the ripple as the motor speed does. The compensation of the current measurement errors is easily implemented to smooth the signal of the integrator output of the d-axis current regulator by subtracting the DC offset value or rescaling the gain of the hall sensor. Therefore, the proposed algorithm has several features: the robustness in the variation of the mechanical parameters, the application of the steady and transient state, the ease of implementation, and less computation time. The MATLAB simulation and experimental results are shown in order to verify the validity of the proposed current compensating algorithm.