• 대한전자공학회논문지TC
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• 제47권4호
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• pp.1-8
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• 2010

이 논문에서는 Sigma-Delta A/D 변환기의 새로운 이득 최적화 방식을 제안한다. 제안된 방식에서는 변조기의 SNR을 최대화하는 다수개의 이득 값 후보군을 먼저 선정한 후에 CIC 데시메이션 필터를 통과시켜 가장 작은 MSE를 보이는 이득 값을 결정하는 방식이다. 실험에 사용된 변조기는 단순화를 위하여 1차의 단일 비트 변조기를 사용하였다. 모의실험을 통하여 변조기의 후보군 중 2위를 기록한 이득 값이 가장 작은 MSE를 보였다. 제안된 방식은 변조기의 SNR을 최대화하는 기존의 아이디어와 데시메이션 필터로 사용되는 CIC 필터의 샘플 합 특성을 이용하여 최적의 이득 값을 결정하는 방식이다.

• 대한전자공학회논문지SD
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• 제42권7호
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• pp.21-26
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• 2005

본 논문에서는 작은 면적을 갖는 저전력 스위치-매트릭스 구조의 델타-시그마 D/A 변환기용 준 디지털 FIR 재생필터를 제안하였다. 제안된 재생필터는 계수를 7 비트로 양자화하고 각 비트 값에 대응하는 전류를 생성하는 7 개의 전류원을 사용하는 구조로 205 개의 탭을 가지며 1419 개의 스위칭 트랜지스터로 구현되었다. 제안된 필터는 0.25 um CMOS공정을 이용하여 설계되었으며 전체 칩 면적은 1.5 mm$^{2}$으로 2.5 V에서 3.8 mW의 소비 전력을 갖는다. 모의실험 결과 104 dB의 다이나믹 레인지와 -84 dB의 대역 밖의 노이즈 허용값을 나타내어 고해상도 오디오용 DAC에 적합하다.

• 전기학회논문지P
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• 제60권1호
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• pp.19-26
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• 2011

In this paper, we designed Interpolation FIR(Finite Impulse Response) filter and 1-bit SDM(Sigma- Delta Modulator) for small digital audio speaker, which has low power consumption and high output characteristics. In order to achieve high linearity and low distortion performance of the systems, we adopt Type I Chevychev FIR filter which has equiripple characteristics in the pass band and proposed high efficient FIR filter structure. SDM is the most efficient modulation technique among the noise shaping techniques. In this paper, we implemented SDM using CIFB(Cascade of Intergrators, Feed-Back) which is generally used in DAC of small digital audio speakers. The proposed SDM structure can achieve high SNR, high-efficiency characteristics and low power consumption in mobile devices. Also considering manufacture of SoC(System on Chip), we performed simulation with Matlab and Verilog HDL to obtain optimal number of operational bits and verified a good experimental results.

• 제어로봇시스템학회논문지
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• 제12권2호
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• pp.174-185
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• 2006

This paper describes a DR construction for land navigation and the sigma point based receding horizon Kalman FIR (SPRHKF) filter for DR/GPS hybrid navigation system. A simple DR construction is adopted to improve the performance both of the pure DR navigation and the DR/GSP hybrid navigation system. In order to overcome the flaws of the EKF, the SPKF is merged with the receding horizon strategy. This filter has several advantages over the EKF, the SPKF, and the RHKF filter. The advantages include the robustness to the system model uncertainty, the initial estimation error, temporary unknown bias, and etc. The computational burden is reduced. Especially, the proposed filter works well even in the case of exiting the unmodeled random walk of the inertial sensors, which can be occurred in the MEMS inertial sensors by temperature variation. Therefore, the SPRHKF filter can provide the navigation information with good quality in the DR/GPS hybrid navigation system for land navigation seamlessly.

• Journal of Communications and Networks
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• 제9권3호
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• pp.219-228
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• 2007

In this paper, we present a novel blind adaptive multiuser detector structure and three robust recursive filters to improve the performance in CDMA environments: Sigma point kalman filter (SPKF), particle filter (PF), and Gaussian mixture sigma point particle filter (GMSPPF). Our proposed robust recursive filters have superior performance over a conventional extended Kalman filter (EKF). The proposed multiuser detector algorithms initially use Kalman prediction form to estimated channel parameters, and unknown data symbol be predicted. Second, based on this predicted data symbol, the robust recursive filters (e.g., GMSPPF) is a refined estimation of joint multipaths and time delays. With these estimated multipaths and time delays, data symbol detection is carried out (Kalman correction form). Computer simulations show that the proposed algorithms outperform the conventional blind multiuser detector with the EKF. Also we can see it provides a more viable means for tracking time-varying amplitudes and time delays in CDMA communication systems, compared to that of the EKF for near-far ratio of 20 dB. For this reason, it is believed that the proposed channel estimators can replace well-known filter such as the EKF.

• Journal of electromagnetic engineering and science
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• 제8권2호
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• pp.76-83
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• 2008

A low power(9 mW) highly-digitized 2.4 GHz receiver for sensor network applications(IEEE 802.15.4 LR-WPAN) is realized by a $0.18{\mu}m$ CMOS process. We adopted a novel receiver architecture adding an intermediate frequency (IF) level detection scheme to a low-power complex fifth-order continuous-time(CT) bandpass L:tl modulator in order to digitalize the receiver. By the continuous-time bandpass architecture, the proposed $\Sigma\Delta$ modulator requires no additional anti-aliasing filter in front of the modulator. Using the IF detector, the achieved dynamic range(DR) of the over-all system is 95 dB at a sampling rate of 64 MHz. This modulator has a bandwidth of 2 MHz centered at 2 MHz. The power consumption of this receiver is 9.0 mW with a 1.8 V power supply.

• 제어로봇시스템학회논문지
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• 제12권8호
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• pp.780-788
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• 2006

This paper deals with INS/GPS tightly coupled integration algorithms using extend Kalman filter (EKF) and unscented Kalman filter (UKF). In the tightly coupled approach, nonlinear pseudorange measurement models are used for the INS/GPS integration Kalman filter. Usually, an EKF is applied for this task, but it may diverge due to poor functional linearization of the nonlinear measurement. The UKF approximates a distribution about the mean using a set of calculated sigma points and achieves an accurate approximation to at least second-order. We introduce the generalized scaled unscented transformation which modifies the sigma points themselves rather than the nonlinear transformation. The generalized scaled method is used to transform the pseudo range measurement of the tightly coupled approach. To compare the performance of the EKF- and UKF-based tightly coupled approach, real van test and simulation have been carried out with feedforward and feedback indirect Kalman filter forms. The results show that the UKF and EKF have an identical performance in case of the feedback filter form, but the superiority of the UKF is demonstrated in case of the feedforward filer form.

• 전기전자학회논문지
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• 제19권2호
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• pp.148-154
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• 2015

차량 전장시스템은 매 순간마다 정확한 인식을 통하여 사용자에게 정확한 경보를 전달해야 한다. 따라서 차량 영상 인식 알고리즘을 적용하기 위하여 빠른 전처리 시스템이 필요하다. 본 논문은 운전자 보조 시스템의 영상 처리를 목적으로 histogram equalization과 편차를 이용한 bilateral Filter를 사용하여 blur 영상을 보정하는 방법에 대해서 제안하였다. 제안한 시스템은 영상 스케일, 평활화, 노이즈 필터, 윤곽선 추출 순으로 총 5단계로 구성되며, bilateral filter의 과 값을 운전자 보조 시스템에서 나타나는 도로의 주행 현상에 적합하게 추출하여 10픽셀 이하의 blur를 기존의 방법들보다 빠르게 처리하였다. 실험 결과는 MATLAB을 사용하여 소요시간 및 PSNR을 구하였으며 기존의 방법과 비교하여 본 논문의 결과가 처리속도가 빠름을 입증하였다.

• 조명전기설비학회논문지
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• 제29권3호
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• pp.69-80
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• 2015

This paper is writing about developing magnet power supply. It is very important for power supply to obtain output current in high precision and high stability. As a switching noise and a power noise are the cause of disrupting the stability of output current, to remove these at the front end, low pass filter with 300Hz cutoff frequency is designed and placed. And also to minimize switching noise of the current into magnet and to stop abrupt fluctuations, output filter should be designed, when doing this, we design it by considering load has high value inductance. As power supply demands the stability of less than 5ppm, high precision 24bit(300nV/bit) analog digital converter is needed. As resolving power of 24bit(300nV/bit) analog digital converter is high, it is also very important to design the input stage of analog digital converter. To remove input noise, 4th order low pass filter is composed. Due to the limitation of clock, to minimize quantization error between 15bit DPWM and output of ADC having 24bit resolving power, ${\Sigma}-{\Delta}$ modulation is used and bit contracted DPWM is constituted. And before implementing, to maximize efficiency, simulink is used.

• Journal of Power Electronics
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• 제12권5호
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• pp.778-786
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• 2012

In this paper, a novel scheme for the condition monitoring of lithium polymer batteries is proposed, based on the sigma-point Kalman filter (SPKF) theory. For this, a runtime-based battery model is derived, from which the state-of-charge (SOC) and the capacity of the battery are accurately predicted. By considering the variation of the serial ohmic resistance ($R_o$) in this model, the estimation performance is improved. Furthermore, with the SPKF, the effects of the sensing noise and disturbance can be compensated and the estimation error due to linearization of the nonlinear battery model is decreased. The effectiveness of the proposed method is verified by Matlab/Simulink simulation and experimental results. The results have shown that in the range of a SOC that is higher than 40%, the estimation error is about 1.2% in the simulation and 1.5% in the experiment. In addition, the convergence time in the SPKF algorithm can be as fast as 300 s.