• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.1
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• pp.179-184
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• 2019

In this paper, we propose a design method of Active Noise Control (ANC) that reduces perceived level of the residual noise. A FELMS (Filtered-E Least Mean Squares) algorithm is used for the ANC system and the NC (noise criteria) is applied as an evaluation criterion of the residual noise. With this structure, we present the allowable spectral shape of the noise shaping filter that minimizes the NC index within the effective operating frequency band of the ANC, and showed that the filter satisfying in the criterion has a lower NC value than the psychoacoustic-based filter used in the previous studies.

• The Journal of the Acoustical Society of Korea
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• v.37 no.5
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• pp.331-337
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• 2018

In this paper, we apply the NR (Noise Rating) to the evaluation of the residual noise of the window type ANC (Active Noise Control) and study the active noise controller for minimizing the NR value in rooms. We proposed a shape of a noise shaping filter of the Filtered-E LMS (Least Mean Square) algorithm that reduces the NR value within the effective operating frequency band of the ANC. The usefulness of the proposed scheme is verified by simulation and showed that the NR value of the residual noise is lower than the filters used in the conventional psychoacoustic ANC.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.11
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• pp.149-156
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• 2012

A digital input class-D audio amplifier is presented for digital hearing aid. The class-D audio amplifier is composed of digital and analog circuits. The analog circuit converts a digital input to a analog audio signal (DAC) with noise suppression in the audio band. An interpolated digital delta-sigma modulator is used to convert data types between digital signal processor (DSP) and digital-to-analog converter (DAC). An 16-bit, 25-kbps pulse code modulated (PCM) input is interpolated to 16-bit, 50-kbps by a digital filter. The output signal of interpolation filter is noise-shaped by a third-order digital sigma-delta modulator (SDM). As a result, 1.5-bit, 3.2-Mbps signal is applied to simple digital to analog converter.