• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.1
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• pp.124-130
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• 2018

The EMG amplitude estimator, which has been investigated as an indicator of muscle force, is of high relevance not only in biomechanical studies but also more and more in clinical applications. This paper presents a new approach to estimate surface EMG amplitude by using the mean spike and mean turn amplitude(MSA and MTA) variables. Surface EMG signals, a total of 198 signals, were recorded from biceps brachii muscle over the range of 20-80%MVC isometric contraction and performance of the MSA and MTA variables applied to amplitude estimation of the EMG signals were investigated. To examine the performance, a SNR(signal-to-noise ratio) was computed from each amplitude estimate. The results of the study indicate that MSA and MTA amplitude estimations with first order whitening filter and 300[ms]-350[ms] moving average window length are optimal and show better performance(mean SNR improvement of 6%-15%) than the most frequently used variables(ARV and RMS).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.8
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• pp.1498-1502
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• 2007

There have been many different definitions of energy functions as the second statistics of a signal. In this paper, using the higher order differential energy function, we propose an algorithm separating the amplitude and frequency components in a discrete sinusoidal signal. The proposed amplitude and frequency estimation methods have less computational requirement than the existing methods. It also shows large computational advantage over the root mean square (RMS) calculation of a signal. The proposed methods can be used in the detection of abnormal events in signals on the power line. Computer simulations show that proposed frequency estimation method can detect the presence of voltage increase or decrease for a short period of time. Also, the proposed estimation methods have been compared with existing methods in terms of estimation error variance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.5
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• pp.843-850
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• 2017

The EMG amplitude estimator, which has been investigated as an indicator of muscle force, is utilized as the control input to artificial prosthetic limbs. This paper describes an application of the optimal EMG amplitude estimator to the surface EMG signals recorded during constant isometric %MVC (maximum voluntary contraction) for 30 seconds and reports on assessing performance of the amplitude estimator from the application. Surface EMG signals, a total of 198 signals, were recorded from biceps brachii muscle over the range of 20-80%MVC isometric contraction. To examine the estimator performance, a SNR(signal-to-noise ratio) was computed from each amplitude estimate. The results of the study indicate that ARV(average rectified value) and RMS(root mean square) amplitude estimation with forth order whitening filter and 250[ms] moving average window length are optimal and showed the mean SNR improvement of about 50%, 40% and 20% for each 20%MVC, 50%MVC and 80%MVC surface EMG signals, respectively.

• Journal of the Korean Geophysical Society
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• v.3 no.4
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• pp.227-234
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• 2000

Amplitude anomalies or bright spots are often linked to hydrocarbon-bearing reservoirs but can also be caused by tuning effect resulting from interference when two reflectors are close together. Tuning effect can be removed from amplitude maps before seismic amplitude and reservoir thickness data are converted into estimates of hydrocarbon accumulations. The most straightforward way of removing tuning effect or 'detuning' is by comparing the reservoir amplitude in seismic data with the response of wedge or thin-bed models and calibrating the reservoir amplitude using the tuning curves from the models. Volumetric estimation for amplitude plays must be based on detuned amplitude maps because hydrocarbon volumes can be significantly overestimated when conventional amplitude maps are used.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.9
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• pp.1436-1443
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• 1989

In this paper, we propose a maximum-likelihood estimation(MLE) method to obtain the location and the amplitude of the pulses in MPE( multi-pulse excitation)-LPC speech synthesis using multi-pulses as excitation source. This MLE method computes the value maximizing the likelihood function with respect to unknown parameters(amplitude and position of the pulses) for the observed data sequence. Thus in the case of overlapped pulses, the method is equivalent to Ozawa's crosscorrelation method, resulting in equal amount of computation and sound quality with the cross-correlation method. We show by computer simulation: the multi-pulses obtained by MLE method are(1) pseudo-periodic in pitch in the case of voicde sound, (2) the pulses are random for unvoiced sound, (3) the pulses change from random to periodic in the interval where the original speech signal changes from unvoiced to voiced. Short time power specta of original speech and syunthesized speech obtained by using multi-pulses as excitation source are quite similar to each other at the formants.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2737-2740
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• 2003

This paper has been studied an algorithm for EMG signal amplitude estimation in noisy environment. The proposed method has the first stage decomposing the row vector from the delayed EMG signal and the second stage computing the eigenvalues by the eigen decomposition from the covariance matrix of the EMG signal matrix. The last stage is the estimation of RMS values from the eigenvalues. The proposed method was effective when the amplitude of the EMG signal is small, which means the signal to noise ratio is low.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.8
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• pp.1193-1198
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• 2012

An instantaneous amplitude (IA) estimator using the symmetric higher order differential energy operator is proposed. The amplitude estimator and the instantaneous frequency (IF) estimator based on the symmetric higher order differential energy operator coincide with the analyzed signal in time, and they show better estimation results than the IA and IF based on the higher order differential energy operator. Various IF and IA estimators are applied to AM-FM signals for the performance comparison. Among the IF and IA estimators, the IF and IA estimators based on the symmetric higher order energy operator show the best estimation accuracy. Then, the IA and IF estimators are applied to the distorted power line signal to show their usefulness as power disturbance detectors.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.3
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• pp.64-70
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• 2009

This paper presents a speech enhancement technique based on generalized Gamma distribution in order to obtain robust speech recognition performance. For robust speech enhancement, the noise estimation based on a spectral noise floor controled recursive averaging spectral values is applied to speech estimation under the generalized Gamma distribution and spectral gain floor. The proposed speech enhancement technique is based on spectral component, spectral amplitude, and log spectral amplitude. The performance of three different methods is measured by recognition accuracy of automatic speech recognition (ASR).

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.1945-1955
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• 2018

High frequency signal injection (HFI) is an alternative method for estimating rotor position of interior permanent magnet synchronous motor (IPMSM). The general method of frequency and amplitude selection is based on error tolerance and experiments, and is usually set with only one group of HF parameters, which is not efficient for different working modes. This paper proposes a novel rotor position estimation scheme by HFI with optimized frequency and amplitude, based on the mathematic model of IPMSM. The requirements for standstill and low-speed operational modes are met by applying this novel scheme. Additionally, the effects of the frequency and amplitude of the injected HF signal on the position estimation results under different operating conditions are analyzed. Furthermore, an optimization method for HF parameter selection is proposed to make the estimation process more efficient under different working conditions according to error tolerance. The effectiveness of the propose scheme is verified by the experiments on an IPMSM motor prototype.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.3
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• pp.649-660
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• 2017

In electronic warfare, the pulse amplitude, one of information of a pulse signal emitted by an enemy, is used for estimating distance from the source and for deinterleaving mixed source signals. An estimate of pulse amplitude is conventionally determined as the maximum magnitude of a Fourier transformed signal within its pulse width which is estimated pre-step in an electronic warfare receiver. However, when frequency modulated signals are received, it is difficult to estimate their pulse amplitudes with this conventional method because the energy of signals is dispersed in frequency domain. In order to overcome this limitation, this paper proposes an enhanced pulse amplitude estimation method which calculates the average power of the received pulse signal in time domain and removes the noise power of the receiver. Simulation results show that even in case the frequency modulated signal is received, the proposed method has the same performance as estimating the pulse amplitude when unmodulated signal is received. In addition, the proposed method is shown to be more robust to an estimation error of pulse width, which affects the estimation performance of pulse amplitude, than the conventional method.