• Title/Summary/Keyword: Variable Notch filter

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A UHF CMOS Variable Gain LNA with Wideband Input Impedance Matching and GSM Interoperability

  • Woo, Doo Hyung;Nam, Ilku;Lee, Ockgoo;Im, Donggu
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제17권4호
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    • pp.499-504
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    • 2017
  • A UHF CMOS variable gain low-noise amplifier (LNA) is designed for mobile digital TV tuners. The proposed LNA adopts a feedback topology to cover a wide frequency range from 474 to 868 MHz, and it supports the notch filter function for the interoperability with the GSM terminal. In order to handle harmonic distortion by strong interferers, the gain of the proposed LNA is step-controlled while keeping almost the same input impedance. The proposed LNA is implemented in a $0.11{\mu}m$ CMOS process and consumes 6 mA at a 1.5 V supply voltage. In the measurement, it shows the power gain of greater than 16 dB, NF of less than 1.7 dB, and IIP3 of greater than -1.7 dBm for the UHF band.

Adaptive Lattice Step-Size Algorithm for Narrowband Interference Suppression in DS/CDMA Systems

  • Benjangkaprasert, Chawalit;Teerasakworakun, Sirirat;Jorphochaudom, Sarinporn;Janchitrapongvej, Kanok
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2003년도 ICCAS
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    • pp.2087-2089
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    • 2003
  • The presence of narrowband interference (NBI) in Direct-sequence code division multiple access (DS/CDMA) systems is an inevitable problem when the interference is strong enough. The improvement in the system performance employs by adaptive narrowband interference suppression techniques. Basically there have been two types of method for narrowband interference suppression estimator/subtracter approaches and transform domain approaches. In this paper the focus is on the type of estimator/subtracter approaches. However, the binary direct sequence (DS) signal, that acts as noise in the prediction process is highly non-Gaussian. The case of a Gaussian interferer with known in an autoregressive (AR) signal or a digital signal and also in a sinusoidal signal (Tone) that included in is paper. The proposed NBI suppression is presence in an adaptive IIR notch filter for lattice structure and more powerful by using a variable step-size algorithm. The simulation results show that the proposed algorithm can significantly increase the convergence rate and improved system performance when compare with adaptive least mean square algorithm (LMS).

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Adaptive Subtraction Method for Removing Variable Powerline Interference of ECG (ECG 신호의 가변적인 전력선 잡음 제거를 위한 적응형 차감기법)

  • Jeon, Hong-Kyu;Cho, Ik-Sung;Kwon, Hyeog-Soong
    • Journal of the Korea Institute of Information and Communication Engineering
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    • 제15권2호
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    • pp.447-454
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    • 2011
  • Power-line interference(PLI) can distort certain regions in analysing the ECG signal. In particular, the regions such as P and R wave that are important element in diagnosing with arrhythmia is expressed as different type of noise according to the case whether power-line frequency is multiples of sampling frequency and or not. Noise characteristics is also divided into linearity and non-linearity. In this paper, adaptive subtraction method for removing variable PLI of ECG signal is proposed. We classify the multiple relationship between power line and sampling frequency as Multiple and Non-multiple. PLI of Linear segment is extracted through moving average filter, PLI of non-linear segment is extracted through the interference component that is extracted in the linear segment and stored in the temporary buffer. The performance of P wave and R wave detection is evaluated by using 119 data record of MIT-BIH arrhythmia database. The achieved scores indicate P wave detection rate of 97.91%, R wave detection rate of 96.66% and P wave detection rate of 99.01%, R wave detection rate of 97.93% accuracy respectively for Notch filter and proposed subtraction method.