• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.847-850
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• 1998

One of the most difficult problem of designing VLSI is a mixed-circuit design, that is to design circuit containing both analog parts and digital parts. Digital to analog converter and analog to digital converter is a typical case. Especially it can be a serious problem when mixed circuit are put into a large digital circuit like microcontroller. However nowadays this problem is settled by separating analog circuit parts outside the IC. This technique is based on converting a digital signal into a pulse sequence. Then an analog signal is obtained by averaging this pulse sequence at the external low-pass filter. An anlog to digital converter is designed using a stochastic logic instead of a traditional PWM (pulse-width modulation) signal and ins implemente dusing FPGa. Stochastic pulse sequence can be made as a simple circuits and moreover can be mathematically processed by simple circuits -AND gates. The spectral property of stochastic pulse sequence method is better than that of PWM method. So it make easy to design a external low-pass filter. This technique has important advantages, especially the reduction of the ADC cost.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1700-1705
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• 2012

This study is focusing on ripple elimination in the band pass filter. There are generally two design methods in IIR filter design, which are a direct method and an indirect one. The indirect design method that designs the digital IIR LPF using the prototype analog LPF is applied to this study. A Butterworth filter and a Chebyshev filter are the typical prototype analog LPFs. This study shows characteristics of the digital IIR LPFs that are transformed from the prototype analog LPFs. The designed Butterworth and Chebyshev IIR LPFs are also designed as the band pass filters by frequency transformation in order to compare with the proposed cascading Chebyshev BPFs. This study shows frequency characteristics between the transformed IIR BPFs and the proposed cascading Chebyshev BPFs as well. The proposed cascading Chebyshev BPF is designed by cascading the different orders of Chebyshev BPFs. The aspect of the cascading filter is offsetting the ripples to descend them while the pass band ripples of the Chebyshev filter are ascending and vice versa. The designed cascading Chebyshev filter shows the flatness and the sharpness, which represent the advantages of Butterworth filter in the pass band and of Chebyshev filter in the transition band respectively. This result verifies the validity of the designed filter.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.397-400
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• 2000

Telecommunication system demands for increased bandwidths and operating frequencies for analog signal processing could be satisfied in the near future by the emergence of a novel technology based on magnetostatic waves propagating in low loss ferrimagnetic films. The magnetostatic wave is the only available technology for analog signal processing directly at millimeter wave frequencies. This paper has been studied the design and implementation of a Magnetostatic Surface Wave band-pass filter for LMDS system.

• Journal of IKEEE
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• v.3 no.1 s.4
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• pp.11-21
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• 1999

This paper has been proposed a structure composed of FIRs and IIR filters as digital interpolation filter to integrate the off-chip analog low-pass filter of audio DAC. The passband ripple (>$0.41{\times}fs$), passband attenuation(>at$0.41{\times}fs$) and stopband attenuation(<$0.59{\times}fs$) of the ${\Delta}{\Sigma}$ modulator output using the proposed digital interpolation filter had ${\pm}0.001[dB]$, -0.0025[dB] and -75[dB], respectively. Also the inband group delay was 30.07/fs[s] and the error of group delay was 0.1672%. Also, the attenuation of stopband has been increased -20[dB] approximately at 65[kHz], out-of-band. Therefore the RC products of analog low-pass filter on chip have been decreased compared with the conventional digital interpolation filter structure.

• Journal of the Korean Institute of Telematics and Electronics
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• v.8 no.5
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• pp.20-26
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• 1971

A function relationship between the envlope rise time and Q v91ue of band pass filter is studied by using the time response to the step and sinusodal inputs. It is discovered that the above relationship is linear in the very low frequency band. The filter was constructed by the Analog computer so as to do the function of 2nd order RC active band pass.

• The Journal of Information Technology
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• v.9 no.1
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• pp.33-39
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• 2006

This study is for the contents of development to the hardware system and software driving algorithm to implement the frequency band of about 7KHz los pass digital filter which has the cut-off frequency of 392Hz by interfacing of a microprocessor with its peripheral analog-to-digital converter chip and digital-to-analog converter chip. The simplicity of digital filter design without difficulty and the implementation of programmed digital filter can be realized by providing the interfacing method to implement the law pass digital filter for the biological signals and the realization method of computer algorithm by a microprocessor.

• Journal of Korea Multimedia Society
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• v.15 no.3
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• pp.364-371
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• 2012

Currently, CMMB(China Mobile Multimedia Broadcasting) and the conventional analog TV broadcasting have transmitted by using UHF(Ultra High Frequency : 474MHz~754MHz) band. Normally, the transmission power of the digital TV broadcasting is lower than the conventional analog TV broadcasting to protect the reception quality of the conventional analog TV broadcasting. The reception sensitivity of CMMB receiver has severely deteriorated due to adjacent the conventional analog TV broadcasting signals which called ACI (Adjacent Channel Interference). To improve the reception sensitivity of a CMMB receiver on ACI environment, this paper proposed a simple method which is tuning a cut off frequency of LPF (Low Pass Filter). From the experiment, the reception sensitivity of CMMB receiver was improved as 11.3dB.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.1
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• pp.1-6
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• 1985

The point spread function of defocussed image is known as two dimensional function, one of rectangular type and Gaussian type function and etc, and the defocussed image can be modeled as the convolved output between original image and the supposed PSF. But, in .case of analog method using the scanning line of TV camera, one dimensional Process can be effective, and it was shown thats the defocussed image can be analyzed as the convolved output betlween the original image and the pule with finite width in the horizontal irection. And uslng TV camera and a analog compound high pass filter, the restoration experiment Is matte and we have got some pictures with remarked improvements.

• The Journal of Korea Robotics Society
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• v.2 no.3
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• pp.205-211
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• 2007

In this paper, the prototype of surface EMG (ElectroMyoGram) sensor is developed for the robotic rehabilitation applications, and the developed sensor is composed of the electrodes, analog signal amplifiers, analog filters, ADC (analog to digital converter), and DSP (digital signal processor) for coding the application example. Since the raw EMG signal is very low voltage, it is amplified by about one thousand times. The artifacts of amplified EMG signal are removed by using the band-pass filter. Also, the processed analog EMG signal is converted into the digital form by using ADC embedded in DSP. The developed sensor shows approximately the linear characteristics between the amplitude values of the sensor signals measured from the biceps brachii of human upper arm and the joint angles of human elbow. Finally, to show the performance of the developed EMG sensor, we suggest the application example about the real-time human elbow motion acquisition by using the developed sensor.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.93-96
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• 2000

This paper has been proposed an audio DAC structure composed of FIRs and IIR filters as digital interpolation filter to integrate the off-chip analog low-pass filter on-a-chip. The passband ripple(< 0.41${\times}$fs), passband attenuation(at 0.41${\times}$fs) and stopband attenuation(> 0.59${\times}$fs) of the Δ$\Sigma$ modulator output using the proposed digital interpolation filter had ${\pm}$ 0.001 ［㏈］, -0.0025［㏈］ and -75［㏈］, respectively. Also the inband group delay was 30.07/fs［s］ and the error of group delay was 0.1672%. Also, the attenuation of stopband has been increased -20［㏈］ approximately at 65［㎑］, out-of-band. Therefore the RC products of analog low-pass filter on chip have been decreased compared with the conventional digital interpolation filter structure.