• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.8 no.6
• /
• pp.620-628
• /
• 1997

When the Chebyshev function is applied to design the waveguide transition, it exhibits poor impedance matching characteristics due to impedance discontinuities at the ends of tapered line. In this paper, an improved Chebyshev function, which is obtained by using the convolution property, is proposed to make improvements on the impedance matching characteristics of the waveguide transition. When rectangular to circular waveguide transition is designed by improved function, then the computed return loss is approximately 5 dB better than the conventional Chebyshev function.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.1
• /
• pp.753-759
• /
• 2020

A modified Chebyshev lowpass filter function with progressively diminishing ripples in the passband is proposed and analyzed in the frequency domain. Owing to the diminishing ripples, the passband magnitude characteristic of the proposed Chebyshev function has improved compared to the classical Chebyshev function. In addition, the phase characteristics of the proposed Chebyshev function were improved considerably compared to that of the Chebyshev function, and the time delay of the proposed function was much simpler and flatter. In addition, the proposed Chebyshev filter was realizable by the passive doubly terminated ladder network delivering maximum power transfer for the order n, even or odd, thus making themselves amenable to low-sensitivity active RC or switched capacitor filters through the simulation techniques. To verify the proposed Chebyshev filter characteristics, a 6th order passive doubly terminated ladder lowpass filter was designed and analyzed using the MATLAB and SPICE program. Thus, the proposed Chebyshev function can remove the drawbacks of the classical Chebyshev function and could be applicable to the design of a filter with an improved filter size, phase, and time delay characteristics for various signal processing.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.12 no.2
• /
• pp.83-91
• /
• 1987

In this paper, the extended inverse Chebyshev function have been derived from Chebyshev function. We presented normalized biquads coefficients of n=5, 6 for passband attenuation Ap(dB)=0.1, 0.2, 0.5, 1.0, 2.0, 3.0 and stopband frequency Ws(rad/s)=1.2, 1.3, 1.4, 1.5, 1.6. A designed low-pass filter from extended inverse Chebyshev transfer function produces the magnitude haracteristic which is maximally flat in the passband and equalripple in the stopband as shown in fig. 3(c), (d). Finally, it showed the magnitude and loss characteristics through realistic circuit simulation, and presented element values.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.13 no.4
• /
• pp.322-331
• /
• 1988

In this thesis, an active RC filter using high order inverse chebyshev function is designed and the design method for cascading blocks with low sensitivity and maximum dynamic range is discussed. To have maximum dynamic range, we have proposed the simple algorithm with a pole-zero pairing, the cascading sequence by flatness matrix and optimum gain distribution for a given transfer function. And 2nd order Block is designed with negative feedback to improve the sensitivity problem which had a defect at active RC circuits. Using the suggested method, we have designed the active RC low pass filter of the normalized 7th order inverse chebyshev function, as a results, we have shown that this accord with the given specification.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.20 no.5
• /
• pp.37-42
• /
• 1983

The elliptic functions have transmission zeros on the imaginary axis and exhibit equal ripples in the stopband as well as in the passband. As a consequence they can be made optimal in the sense that the transition band is minimal. However the time domain behaviors turned out to be inferior to those of Chebyshev and Butterworth responses. This paper investigates the unit step responses and impulse responses in order to analyze the effects of various parameters such as passband attenuation, stopband frequencies M. etc., The following are the prominent features. Step responses of elliptic filters rise faster and produce larger overshoots and undershoots with higher natural frequencies. In the case of even functions, the initial values are non-zero which decreases as $\omega$s increases. Unlike Butter-worth or Chebyshev cases the impulse responses start with nonzero valses which also decrease as $\omega$s or order of the function increases. Eight figures are included to illustrate above analysis.

• Proceedings of the Korean Information Science Society Conference
• /
• 2003.04d
• /
• pp.70-72
• /
• 2003

전자계 산란의 시간영역 신호는 대응하는 주파수 영역 응답에 대해서도 동시에 효율적인 방법으로 나타낼 수 있는 이유는 다항식의 직교하는 성질 때문이다. 직교 다항식을 이용함으로써, 이른 시간과 낮은 주파수 영역을 동시에 추정할 수 있다 그 접근법은 CGM(Conjugate Gradient Method)방법과 간단한 DFT(Discrete Fourier transform)에 의거한다. 본 논문에서는 Bessel-Chebyshev 함수를 이용한 이른 시간과 낮은 주파수영역 응답을 동시에 추정하기 위한 접근의 방법을 제시하고, 구현하였다. 오직 이른 시간과 낮은 주파수 정보를 필요로 하기 때문에 이 방법으로 계산시 반복계산의 수렴속도가 무척 빠르다는 이점이 있어, 신속한 정보를 얻을 수 있다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.16 no.4 s.95
• /
• pp.438-446
• /
• 2005

In this paper, the modified generalized Chebyshev rational function is presented. The new element values of prototype low pass filter are obtained by network synthesis using this rational function. This proposed filter has an equal ripple passband as same as conventional generalized Chebyshev filter, but unlike conventional filter which has only one attenuation pole at finite frequency, the proposed filter has two different from each other attenuation pole in stopband. If the harmonic frequency is set to the second attenuation pole frequency, this harmonic is suppressed efficiently. Furthermore, since the location of the second attenuation pole can be arbitrary adjusted. our filters are very available for the realization of wide stopband, particularly.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.31B no.5
• /
• pp.88-94
• /
• 1994

Inverse Chebyshev function can realize the same order of Chebyshev function nuder the same specification. In general, inverse Chebyshev function has the preferable characteristics in terms of the delay characteristics and the time-domain performances compare with Chebyshev function. However, for the even order n, inverse Chebyshev function does not realize in the doubly-terminated ladder network which has preferable sensitivity characteristics because of the finite value at ${\omega}={\infty}$. In this paper, the modified inverse Chebyshev function with $\mid$H($j^{\infty}$$\mid$=0 s proposed to realize the passive doubly-terminated ladder network for the n even or odd. The modified inverse Chebyshev function characteristics ars studied in the frequency and time domain, and then, realize the passive doubly-terminated ladder network.

• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.795-798
• /
• 1998

In this paper, a new class of bandpass filter using a modified Chebyshev lowpass filter function is described. The prosposed bandpass filter which exhibits diminishing ripples in the passband has maximum value at the center frequency. Due to the lower pole-Q, the performance in the frequency and time domains is improved as compared with the classical Chebyshev bandpass filter.