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Yegui Xiao 대한전자공학회 2008 ITC-CSCC :International Technical Conference on Ci Vol.2008 No.7
In a conventional narrowband active noise control system, each reference cosine wave has to be filtered by an estimate of the secondary-path. We call this part x-filtering block. The number of x-filtering blocks is equal to the number of targeted frequencies. The computational cost of the system due to the x-filtering operations may form a bottleneck in real system implementation. In this paper, we propose a new narrowband ANC system structure which requires only one xfiltering block regardless of q. All the cosine waves are combined as an input to a x-filtering block whose output is decomposed by an efficient bandpass filter bank into filtered cosine waves for the FXLMS that follows. As a result, the computaional cost of the system is considerably reduced. The new structure is further implanted in a recently developed ANC system that is capable of mitigating the frequency mismatch (FM). Simulations demonstrate that the new systems present robust performance very similar to that of their counterparts, but enjoy considerable advantages in system implementation.
A NEW NARROWBAND ACTIVE NOISE CONTROL SYSTEM USING IIR NOTCH FILTERS AND MAGNITUDE/PHASE ADJUSTERS
Yegui Xiao 대한전자공학회 2007 ITC-CSCC :International Technical Conference on Ci Vol.2007 No.7
In this paper, we propose a new narrowband active noise control (ANC) system that consists of a cascaded adaptive IIR notch filter bank and a paralleled FIR filter bank with twoweight FIR magnitude/phase adjusters (MPA). The adaptive IIR notch filter used is updated by a gradient-based algorithm, while the MPAs are adjusted by a filtered-x LMS (FXLMS) algorithm. Extensive simulations are performed to demonstrate the effectiveness of the proposed ANC system.
FETAL ECG EXTRACTION USING MULTI-SENSORY LINEAR NOISE CANCELLER WITH MULTIPLE REFERENCE CHANNELS
Yegui Xiao,Kohe Yokota,Hisahito Ishitake,Keiko Ueda,Tomoaki Ikeda 대한전자공학회 2009 ITC-CSCC :International Technical Conference on Ci Vol.2009 No.7
Recently, fetal ECG extraction has attracted much attention among DSP researchers, because accurate extraction is expected to make early detection and treatment of fetal diseases possible and thus contribute to the fetus health care and safety of delivery. In this paper, we propose a new extraction system that uses a multi-sensory linear noise canceller with multiple reference channels. In this extraction system, multiple measurements (noisy fetal ECG signals) obtained in the abdominal area are used as primary signals, while multiple time sequences acquired in the thoracic area (maternal ECG signals) are applied as reference signals to the reference channels equipped with adaptive FIR filters. Superior effectiveness of the proposed system is investigated by applying it to a real data set.
DYNAMIC PROPERTIES OF ACTIVE NOISE CONTROL WITH AUXILIARY NOISE SCALED BY RESIDUAL NOISE SIGNAL
Jian Liu,Yegui Xiao,Jinwei Sun 대한전자공학회 2009 ITC-CSCC :International Technical Conference on Ci Vol.2009 No.7
In an active noise control (ANC) system with online secondary-path modeling based on auxiliary white noise injection, the residual noise power may be reduced by scaling the auxiliary noise with a function of the residual noise signal. In this paper, dynamics of a filtered-X LMS (FXLMS) based narrowband ANC system with online secondary-path modeling using an auxiliary white noise scaled by one-sample-delayed residual noise signal is analyzed. Difference equations governing the dynamics of the system are derived and discussed. Extensive simulations are conducted to illustrate the effectiveness of auxiliary noise scaling and the validity of the analytical results.