• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.681-684
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• 2000

Gradient-type algorithms for adaptive IIR notch filters are very attractive in terms of both performances and computational requirements. Generally, it is quite difficult to assess their performances analytically. There have been several trials to analyze such adaptive algorithms as the sign and the plain gradient algorithms for some types of adaptive IIR notch filters, but many of them still remain unexplored. Furthermore, analysis techniques used in those trials can not be directly applied to different types of adaptive IIR notch filters. This paper presents a detailed performance analysis of the sign algorithm for a well-known adaptive IIR notch filter with constrained poles and zeros, which can not be done by just applying the related existing analysis techniques, and therefore has not been attempted yet. The steady-state estimation error and mean square error (MSE) of the algorithm are derived in closed forms. Stability bounds of the algorithm are also assessed. extensive simulations are conducted to support the analytical findings.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.3
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• pp.58-63
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• 2007

GPS signal is vulnerable to intentional and unintentional interferences since it has a very weak signal power and its structure is well-known. Among the interference rejecting techniques, the ATF is being generally used as a pre-correlation technique. However, it does not have a design parameter relating to the notch width, resulting in the spectral loss around frequency of the interference. The IIR notch filter has a design parameter relating to the notch width and can generate a sharp notch for the CW interference. In this paper, an adaptive IIR notch filter is proposed and the performance is evaluated using software signal generator and real measurements.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1991.10a
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• pp.119-122
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• 1991

In this paper, a new adaptive IIR notch filter employing all pass filter is proposed. Proposed all pass filter is composed of all pole and all zero sections, each of which utilizes modulation lattice filter [11]. And, adaption algorithm for proposed notch filter is also derived. In addition, the error surface for proposed IIR adaptive notch filter is analyzed. Computer simulation results reveal that the proposed adaptation algorithm works well for low SNR(signal to noise ratio) single and multiple sinusoids. And it is shown that for estimation time varying frequency, the parameter which is related to notch bandwidth is important than any other parameters.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.65-68
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• 2003

This paper presents a design and construction of IIR multiple notch filter by modifying the pole-zero placement with least square estimation to find the appropriate gain and pole positions for the filter within a unit circle in z-plane. The appropriated gain and pole position will render the controllable unit gain of filter magnitude. Algorithm design and system simulation are performed on MATLAB while the actual implementation is done on the TMS320C31 digital signal processing board.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.848-851
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• 2005

This paper proposes a design of IIR notch filter with modified pole placements. The pole angle is derived from quadratic programming to find the appropriate pole position on the unit circle in z-plane in order to achieve the symmetry of the amplitude response. The simulation results are shown when compared with the conventional design technique. Moreover, it uses the TMS320C31 DSP chip for hardware implementation. Finally, the hardware implementation can be applied to removal of ECG baseline wander and elimination of AC power line interference in ECG signal.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1222-1227
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• 2005

In this paper, an efficient scheme of the adaptive notch filter is presented for rejecting the narrow bandwidth interferences(NBI) in GPS receiver. Designed is the lattice IIR double notch filter for more efficient suppression of the NBI with less computational complexity. The algorithm is of recursive prediction error form and uses a special constrained model of IIR with a minimal number of parameters. This paper chooses seven different jamming scenarios including one without jamming for evaluating the proposed filter algorithm. The simulation results to the jamming scenarios show that the proposed algorithm adjusts the double notch filter effectively for the given JSR, and provides better SNR than the conventional algorithms. Finally, it is shown that the advantages of the proposed filter algorithm can range as high as JSR 79dB in time domain processing. Also, the ADNF(adaptive double notch filter) guarantees that more than SNR 10dB of GPS receiver can be always maintained. In conclusion, there is enough evidence to believe that the proposed algorithm will perform quite well for removing interference signals.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1573-1576
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• 2004

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.4
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• pp.719-726
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• 1987

In this paper, an adaptive IIR (infinite impulse response) notch filter of lattice type is constructed and its adaptation algorithm is proposed for the detection and retrieval of a sine wave signal embedded in noise. A modified method which adapts only one coefficient of the filter is also suggested. All these methods adapt the coefficients while keepting the poles of the filter inside the unit circle on z-plane, and thus they satisfy the condition on the stability of the IIR filter after it has converged. To investigate the convergence characteristics of these methods such as convergence speed and output S/N ratio, intensive computer simulation has been performed by varying the frequency of the sine wave and the input S/N ratio. And the results of the simulation have been compared to those of Rao and Kung's which shows relatively fast convergence speed. The methods proposed here, especially the second one. shows faster convergence speed and higher output S/N ratio than the Rao and Kung's.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.3
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• pp.71-78
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• 2009

In this study, estimation of heart rate from measured PPG signal is proposed. PPG signal is to be measured blood flow in a blood vessel effected by systole and diastole. PPG sianl has single frequency so that PPG frequency can be tracked by 2nd IIR adaptive notch filter. PPG frequency is obtained continually from updating filter coefficient throughout adaptive algorithm and then the heart rate of human is approximately estimated.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.4B
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• pp.447-456
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• 2001

본 논문에서는 DS-확산대역 시스템에서 격자형 IIR 노치필터를 이용하여 협대역 간섭신호를 제거한다. 이를 위하여 우선 갑섭신호의 주파수와 파워가 격자형 IIR 노치필터에 의ㅏ형 추정된다. 그리고 또 다른 IIR 노치필터를 수긴기 닾에 위치시키고 노치의 위치가 추정된 갑섭신호의 주파수에 있도록 한다. 그러나 단워원 위에 영점이 존재하는 IIR 노치필터는 간섭신호 뿐만 아니라 노치부분의 신호 성분도 제거하므로 데이터의 왜곡이 발생하게 된다. 따라서 이러한 데이터의 왜곡을 줄이기 위해서 필터의 노치 깊이를 조절하는 알고리듬을 개발하였다. 이를 위해 노치필터 출력의 신호 대 잡음비를 필터 파라미터에 대한 식으로 유도하고 이를 최대로 하는 최적의 노치 깊이를 구하였다. 시뮬레이션 결과 제안한 알고리듬이 기존의 FIR 노치필터나 FIR LMS 알고리듬에 비해 좋은 성능을 갖는다는 것을 확인할 수 있다.