• Journal of Korea Society of Digital Industry and Information Management
• /
• v.11 no.1
• /
• pp.171-182
• /
• 2015

The general wavelet transform has profitable property in non-stationary signal analysis specially. The tunable Q-factor wavelet transform is a fully-discrete wavelet transform for which the Q-factor Q and the asymptotic redundancy r, of the transform are easily and independently specified. In particular, the specified parameters Q and r can be real-valued. Therefore, by tuning Q, the oscillatory behavior of the wavelet can be chosen to match the oscillatory behavior of the signal of interest, so as to enhance the sparsity of a sparse signal representation. The TQWT is well suited to fast algorithms for sparsity-based inverse problems because it is a Parseval frame, easily invertible, and can be efficiently implemented. The transform is based on a real valued scaling factor and is implemented using a perfect reconstruction over-sampled filter bank with real-valued sampling factors. The transform is parameterized by its Q-factor and its over-sampling rate, with modest over-sampling rates being sufficient for the analysis/synthesis functions to be well localized. This paper describes filter design of 2D discrete-time wavelet transform for which the Q-factor is easily specified. With the advantage of this transform, perfect reconstruction filter design and implementation for performance improvement are focused in this paper. Hence, the 2D transform can be tuned according to the oscillatory behavior of the image signal to which it is applied. Therefore, application for performance improvement in multimedia communication field was evaluated.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.31.5-31
• /
• 2001

In conventional perturbation estimators such as disturbance observers(DOB) [1, 2] or time-delayed controllers(TDC) [3{5}, the low pass filter(so-called Q-filter) plays an important role in the stability and performance. However, a general design guideline or analysis for the Q-filter has not been researched yet. In this paper, a guideline for the design of discrete Q-filter is suggested in terms of the analysis of the relationship between the filter parameters and stability performance robustness in discrete-time domain. The analysis clarifies the discrete-time effect of the perturbation estimator and provides a transparent relationship between performance and robustness depending ...

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.59 no.1
• /
• pp.64-70
• /
• 2010

This paper presents how to decide on tuning factor(${\delta}$) and quality factor(Q) values in design of single-tuned passive harmonic filters. Tuning factor(${\delta}$) and quality factor(Q) values have to consider before decision on circuit parameters of passive filters. A Study on these two value has not been scarcely performed and only experienced values has been used in passive harmonic filter design by far. As a experienced value, in cases of 5th and 7th filter, tuning factor(${\delta}$) is about 0.94 and 0.96 respectively and quality factor(Q) is, in all cases of, 50. If Single-tuned passive harmonic filter will be off-tuned, performance of filter will be decreased steeply and occur to parallel resonance between system reactance and filter capacitance. Therefore During the operation, In order not to off-tuning, Filter must be tuned at former order than actual tuning order. This is the same that total impedance of filter must have a reactive impedance. In this paper, Tuning factor(${\delta}$) is decided via example of real system and using the bode-plot and then performance of filters confirmed by filter current absorbtion rate. And Quality factor(Q) decided using the bode plot in example system and then performance of filters confirmed by filter current absorbtion rate also, which makes a calculated filter parameters to satisfy IEEE-519 distortion limits. Finally, Performance of the designed passive harmonic filter using the tuning factor(${\delta}$) and quality factor(Q) values, decided in this paper is verified by experiment and shows that 5th, 7th, 9th, 11th and 13th current harmonic distortions are decreased within IEEE-519 distortion limits, respectively.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.11
• /
• pp.123-129
• /
• 2016

Disturbance Observer(DOB) based control is considered for the purpose of the balancing performance enhancement in a single-wheel robot. Design of DOB can be folded into two parts, the inverse model of the plant and the Q-filter. The inverse model is derived from the inverted stick model and a Q-filter is designed to stabilize the inverse model. In this paper, a Q31 filter is designed and its effect is evaluated by experimental studies. The time constant provides a complimentary characteristic between the disturbance suppression and the sensor noise immunity. Therefore, suitable selection of the time-constant must be considered. Comparative experiments are conducted to investigate the control performances when three different Q filters are respectively applied in the DOB. Through the analysis of the experimental results, a time constant is designed to have a proper value in the design of DOB for balancing control of a single-wheel robot.

• Journal of Institute of Control, Robotics and Systems
• /
• v.10 no.3
• /
• pp.225-231
• /
• 2004

Disturbance observer (DOB) has been studied extensively and applied to many motion control fields during the last decades, but relatively few studies have been devoted to the development of analytic, systematic design methods for DOB itself, This paper thus aims to provide an analytic, systematic design method for DOB. To do this, DOB is structurally analyzed and the generalized disturbance compensation framework named robust internal-loop compensator (RIC) is introduced. Through this, the inherent equivalence between DOB and RIC is found, and the mixed sensitivity optimization problem of DOB is solved. Q-filter design is completely separated from the mixed sensitivity optimization problems of DOB although the proposed method has implicit .elation with Q-filter. Also, although the Q-fille. is separately designed with sensitivity function, the proposed DOB framework has the exactly same characteristic as the original DOB.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.7
• /
• pp.3425-3430
• /
• 2013

The fast-growing market in wireless communications has led to the development of multi-standard mobile terminals. In this paper, a frequency-tunable active RC bandpass filter for multi-standards wireless communication system is designed using an active inductor. The conventional bandpass filter design methods employ the high order filter or high quality factor Q to improve the stopband attenuation characteristics and frequency selectivity of the passband. The proposed bandpass filter based on the high Q active inductor has an improved frequency characteristics. The center frequency and gain of the designed bandpass filter is tuned by employing the tuning circuit. We have performed the simulation using TSMC $0.18{\mu}m$ process parameter to analyze the characteristics of the designed active RC bandpass filter. The bandpass filter with Q=20.5 has 90MHz half power bandwidth at the center frequency of 1.86GHz. Moreover, the center frequency of the proposed bandpass filter can be tuned between 1.86~2.38GHz for the multi-standards wireless communication system using the capacitor of the tuning circuit.

• Proceedings of the IEEK Conference
• /
• 2000.06a
• /
• pp.205-208
• /
• 2000

In this paper, we design Tracking Filter that is principal component of Frequency Hopping System. This filter can acquire hopping pattern in short time and track it at high speed. This is high Q, narrowband, RF filter whose center frequency is controlled digitally between 30MHz ∼ 88MHz.

• The Journal of the Acoustical Society of Korea
• /
• v.19 no.3
• /
• pp.63-71
• /
• 2000

A new type of second-order digital peaking filters for professional-quality digital audio system is proposed whose frequency response can be elaborately controlled throughout the composite structure of a standard band-pass filter and a 0-dB bypass gain. The proposed method for designing the peaking filter uses the Q-compensation technique to prevent the Q-distortion caused by the variation of the gain factor and is reduced into a compact form which is proper to the real-time implementation. Methods are examined for computing its coefficients, which are exact and very straightforward to compute with small amount of the system resources.

• Proceedings of the KIEE Conference
• /
• 2006.10c
• /
• pp.187-189
• /
• 2006

In mechanical system, gear trains have backlash innately. With the presence of inherent backlash, the overall system performance is limited in many practical control systems. It has been reported that a disturbance observer has the property of effective removing disturbance and cutting measurement noise off. The plant is remodeled with modified disturbance observer to observe and compensate backlash characteristics. And this paper describes a method to design Q filter and to analyze the effects of disturbance and measurement noise to the output. It is shown that the vibration and tracking error caused by backlash were decreased and the time constant and relative degree are important factor to design Q filter.

• The Journal of the Acoustical Society of Korea
• /
• v.19 no.5
• /
• pp.79-83
• /
• 2000

When passband ripple α/sub p/ and stopband attenuation α/sub s/ at the w/sub s/ where the stopband begins are specified in filter design, △α/sub s/ usually exceeds the specification by △α/sub s/ due to the necessity that the order n of the filter function be an integer. In this paper, we apply a trade-off method to remove the excess stopband attenuation △α/sub s/ for reducing the value of pole-Q and improving the characteristics of the Chebyshev filter function. We also apply the trade-off method of pole-Q reduction to the modified Chebyshev function, and then the 4 types of function have been analyzed to compare in frequency and time domain characteristics. The trade-off method reduces the pole-Q which influences the filter characteristics to maximum 49.6% without increase of the order n. Thus implies that they have the improved characteristics such as the reduced passband ripple and flatter delay characteristics as compared Chebyshev filter function before trade-off. And the unit step response shows shorter delay time and settling time in time domain performance.