• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.99-101
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• 1995

This paper presents a method for the extraction of the fundamental frequency from transient signals using Prony's analysis. There exists transient voltages and current after a fault including an exponetially decaying do component and harmonics as well as the fundamental frequency. As Prony's analysis uses exponetially decaying functions as basis functions it can extract the fundamental frequency precisely from transient signals. The results of comparison with DFT are also shown.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.5
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• pp.109-116
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• 2010

In this paper, we propose a method for extracting predominant melody of polyphonic music based on harmonic structure. Since polyphonic music contains multiple sound sources, the process of melody detection consists of extraction of multiple fundamental frequencies and determination of predominant melody using those fundamental frequencies. Harmonic structure is an important feature parameter of monophonic signal that has spectral peaks at the integer multiples of its fundamental frequency. We extract all fundamental frequency candidates contained in the polyphonic signal by verifying the required condition of harmonic structure. Then, we combine those harmonic peaks corresponding to each extracted fundamental frequency and assign a rank to each after calculating its harmonic average energy. We finally run pitch tracking based on the rank of extracted fundamental frequency and continuity of fundamental frequency, and determine the predominant melody. We measure the performance of proposed method using ADC 2004 DB and 100 Korean pop songs in terms of MIREX 2005 evaluation metrics, and pitch accuracy of 90.42% is obtained.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.7
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• pp.29-36
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• 2013

In this paper, a new DC offset elimination filter is proposed for an accurate phasor extraction of fundamental frequency component. The proposed method can eliminate a DC offset component which is decayed exponentially. The proposed method uses only one cycle of data for phasor extraction computation, which does not need to preset the time constant of the DC offset component. Also, the other advantages of the proposed method is that gain compensation or phase compensation is not required after filtering. Simulations using ATP were performed to evaluate the performance of the proposed filter method, and the results were compared to the ones obtained by conventional methods.

• Proceedings of the Acoustical Society of Korea Conference
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• 1985.10a
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• pp.107-111
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• 1985

• The KIPS Transactions:PartB
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• v.15B no.6
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• pp.595-602
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• 2008

The focused word of each sentence is a help in recognizing and understanding spoken Korean. To find the method of focused word spotting at spoken speech signal, we made an analysis of the average and variance of Fundamental Frequency and the average energy extracted from a focused word and the other words in a sentence by experiments with the speech data from 100 spoken sentences. The result showed that focused words have either higher relative average F0 or higher relative variances of F0 than other words. Our findings are to make a contribution to getting prosodic characteristics of spoken Korean and keyword extraction based on natural language processing.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.164-166
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• 2012

In this paper, we proposed a method for extracting predominant melody of polyphonic music based on harmonic structure. Harmonic structure is an important feature parameter of monophonic signal that has spectral peaks at the integer multiples of its fundamental frequency. We extract all fundamental frequency candidates contained in the polyphonic signal by verifying the required condition of harmonic structure. Then, we combine those harmonic peaks corresponding to each extracted fundamental frequency and assign a rank to each after calculating its harmonic average energy. We run pitch tracking based on the rank of extracted fundamental frequency and continuity of fundamental frequency, and determine the predominant melody. For the query by singing/humming (QbSH) task, we proposed Dynamic Time Warping (DTW) based matching engine. Our system reduces false alarm by combining the distances of multiple DTW processes. To improve the performance, we introduced the asymmetric sense, pitch level compensation, and distance intransitiveness to DTW algorithm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3558-3562
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• 2010

The exact fundamental frequency (pitch) extraction is important in speech signal processing. However the exact pitch extraction from speech signal is very difficult due to the effect of formant and transitional amplitude. So in this paper, the pitch is detected after flattening the spectrum in frequency region by proposed algorithm for minimized harmonics variance value. Experimental result showed the proposed method appeared an outstanding performance in compared with LPC, Cepstrum. Also, the results show the proposed method is better than conventional method.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.931-936
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• 1994

Although an ideal low-pass filter is not physically realizable, it can be approximated on the basis of time reversal techniques. In this paper, we describe a method to approximately implement the ideal low-pass filter and apply it to the pitch extraction system. Experimental results show that our method is effective to estimate the fundamental frequency of the speech signal.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1610-1614
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• 1987

The harmonies of the fundamental frequency in speech signal make a minute line spectrum in frequency domain. In this paper, we propose a new algorithm to detect a pitch interval in voiced sound based on the fact that the number of harmonies can represent the period of the pitch in the time domain.

• The Journal of the Acoustical Society of Korea
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• v.21 no.3
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• pp.310-314
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• 2002

The exact pitch (fundamental frequency) extraction is important in speech signal processing like speech recognition, speech analysis and synthesis. However the exact pitch extraction from speech signal is very difficult due to the effect of formant and transitional amplitude. So in this paper, the pitch is detected after the elimination of formant ingredients by flattening the spectrum in frequency region. The effect of the transition and change of phoneme is low in frequency region. In this paper we proposed the new flattening method of log spectrum and the performance was compared with LPC method and Cepstrum method. The results show the proposed method is better than conventional method.