• Title/Summary/Keyword: RF Noise

Search Result 620, Processing Time 0.027 seconds

Noise Reduction in an Inductively Coupled RFID System Using a Dual Coil Antenna (유도결합 RFID 시스템에서 이중 코일 안테나를 이용한 잡음의 감소)

  • Lee, Seong-Ho
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.18 no.6 s.121
    • /
    • pp.648-655
    • /
    • 2007
  • In this paper, we introduce a dual coil antenna which is useful for reducing the effects of radio frequency noise in an RFID system. A dual coil antenna is composed of two identical coils that are connected in series. The noise voltages in the two coils almost disappear when they are added because the magnitudes are equal and the polarities are opposite. The noise in an RFID reader with a dual coil antenna was 15 dB lower than that with a single coil antenna.

A Non-linear Variant of Improved Robust Fuzzy PCA (잡음 민감성이 향상된 주성분 분석 기법의 비선형 변형)

  • Heo, Gyeong-Yong;Seo, Jin-Seok;Lee, Im-Geun
    • Journal of the Korea Society of Computer and Information
    • /
    • v.16 no.4
    • /
    • pp.15-22
    • /
    • 2011
  • Principal component analysis (PCA) is a well-known method for dimensionality reduction and feature extraction while maintaining most of the variation in data. Although PCA has been applied in many areas successfully, it is sensitive to outliers and only valid for Gaussian distributions. Several variants of PCA have been proposed to resolve noise sensitivity and, among the variants, improved robust fuzzy PCA (RF-PCA2) demonstrated promising results. RF-PCA, however, is still a linear algorithm that cannot accommodate non-Gaussian distributions. In this paper, a non-linear algorithm that combines RF-PCA2 and kernel PCA (K-PCA), called improved robust kernel fuzzy PCA (RKF-PCA2), is introduced. The kernel methods make it to accommodate non-Gaussian distributions. RKF-PCA2 inherits noise robustness from RF-PCA2 and non-linearity from K-PCA. RKF-PCA2 outperforms previous methods in handling non-Gaussian distributions in a noise robust way. Experimental results also support this.

RFID Noise Reduction Using a Multi-Coil Antenna (다중 코일 안테나를 이용한 RFID 유도 잡음의 감소)

  • Lee, Seong-Ho
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.19 no.6
    • /
    • pp.603-611
    • /
    • 2008
  • In this paper, we introduce a multi-coil antenna which is useful for reducing the effects of radio frequency noise in an inductively coupled RFID system. A multi-coil antenna is composed of a central coil and four subsidiary coils that are connected in series. A multi-coil antenna is designed so that the total noise disappear when the induced voltages of a central coil and subsidiary coils are added. The noise in a multi-coil antenna was about 30 dB lower than that in a single coil antenna. The multi-coil antenna is very effective in noise reduction even in an environment that the spatial distribution of RF noise is changed abruptly, and the induced noise was about 16 dB lower than that in a dual coil antenna.

Basic RF Coils Used in Multi-channel RF Coil and Its B1 Field Distribution for Magnetic Resonance Imaging System (자기공명영상 촬영 장치에서 다채널 RF Coil에 이용되는 기본 구조 RF Coil의 B1 Field 분석)

  • Kim, Yong-Gwon
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.11 no.12
    • /
    • pp.4891-4895
    • /
    • 2010
  • RF coil is an important component of the Magnetic Resonance Imaging (MRI) system and the performance of RF coil is one of major factors for high SNR images. Sensitivity and RF field uniformity are parameters for evaluating RF coil performance. Since the B1 field is induced by RF coil, MR signal is strongly affected by RF coil structure and arrangement. In receiving MR signal, the RF coil sensitivity to MR Signal is also determined by the induced B1 field of RF coil. Therefore, the spatial distribution of B1 field must be verified. In this work, we performed computer simulation of the basic RF coil structures using Matlab and verified their sensitivity and uniformity through their B1 field distribution. This work will be useful for the advanced multi-channel RF coil design.

DC and RF Characteristics of $Si_{0.8}Ge_{0.2}$ pMOSFETs: Enhanced Operation Speed and Low 1/f Noise

  • Song, Young-Joo;Shim, Kyu-Hwan;Kang, Jin-Young;Cho, Kyoung-Ik
    • ETRI Journal
    • /
    • v.25 no.3
    • /
    • pp.203-209
    • /
    • 2003
  • This paper reports on our investigation of DC and RF characteristics of p-channel metal oxide semiconductor field effect transistors (pMOSFETs) with a compressively strained $Si_{0.8}Ge_{0.2}$ channel. Because of enhanced hole mobility in the $Si_{0.8}Ge_{0.2}$ buried layer, the $Si_{0.8}Ge_{0.2}$ pMOSFET showed improved DC and RF characteristics. We demonstrate that the 1/f noise in the $Si_{0.8}Ge_{0.2}$ pMOSFET was much lower than that in the all-Si counterpart, regardless of gate-oxide degradation by electrical stress. These results suggest that the $Si_{0.8}Ge_{0.2}$ pMOSFET is suitable for RF applications that require high speed and low 1/f noise.

  • PDF

System Level Design of CDMA RF Receivers Using the Receiver Noise Equation

  • Kim, Ji-Hoon;Lee, Han-Dug;Yoo, Hyung-Joun
    • Proceedings of the IEEK Conference
    • /
    • 2002.07a
    • /
    • pp.329-332
    • /
    • 2002
  • In this paper a common design method fur RF receivers of different CDMA standards is introduced. The method adopted a new equation, receiver noise equation, for the analysis of each standard. The test conditions for RF receivers in four different CDMA standards, CDMA cellular, PCS, WCDMA, and cdma2000 are analyzed based on the receiver noise equation. With the result of the analysis, the specifications fer RF receivers of different CDMA standards are derived.

  • PDF

A 0.13-㎛ Zero-IF CMOS RF Receiver for LTE-Advanced Systems

  • Seo, Youngho;Lai, Thanhson;Kim, Changwan
    • Journal of electromagnetic engineering and science
    • /
    • v.14 no.2
    • /
    • pp.61-67
    • /
    • 2014
  • This paper presents a zero-IF CMOS RF receiver, which supports three channel bandwidths of 5/10/40MHz for LTE-Advanced systems. The receiver operates at IMT-band of 2,500 to 2,690MHz. The simulated noise figure of the overall receiver is 1.6 dB at 7MHz (7.5 dB at 7.5 kHz). The receiver is composed of two parts: an RF front-end and a baseband circuit. In the RF front-end, a RF input signal is amplified by a low noise amplifier and $G_m$ with configurable gain steps (41/35/29/23 dB) with optimized noise and linearity performances for a wide dynamic range. The proposed baseband circuit provides a -1 dB cutoff frequency of up to 40MHz using a proposed wideband OP-amp, which has a phase margin of $77^{\circ}$ and an unit-gain bandwidth of 2.04 GHz. The proposed zero-IF CMOS RF receiver has been implemented in $0.13-{\mu}m$ CMOS technology and consumes 116 (for high gain mode)/106 (for low gain mode) mA from a 1.2 V supply voltage. The measurement of a fabricated chip for a 10-MHz 3G LTE input signal with 16-QAM shows more than 8.3 dB of minimum signal-to-noise ratio, while receiving the input channel power from -88 to -12 dBm.

Design of a New Harmonic Noise Frequency Filtering Down-Converter in InGaP/GaAs HBT Process

  • Wang, Cong;Yoon, Jae-Ho;Kim, Nam-Young
    • Journal of electromagnetic engineering and science
    • /
    • v.9 no.2
    • /
    • pp.98-104
    • /
    • 2009
  • An InGaP/GaAs MMIC LC VCO designed with Harmonic Noise Frequency Filtering(HNFF) technique is presented. In this VCO, internal inductance is found to lower the phase noise, based on an analytic understanding of phase noise. This VCO directly drives the on-chip double balanced mixer to convert RF carrier to IF frequency through local oscillator. Furthermore, final power performance is improved by output amplifier. This paper presents the design for a 1.721 GHz enhanced LC VCO, high power double balance mixer, and output amplifier that have been designed to optimize low phase noise and high output power. The presented asymmetric inductance tank(AIT) VCO exhibited a phase noise of -133.96 dBc/Hz at 1 MHz offset and a tuning range from 1.46 GHz to 1.721 GHz. In measurement, on-chip down-converter shows a third-order input intercept point(IIP3) of 12.55 dBm, a third-order output intercept point(OIP3) of 21.45 dBm, an RF return loss of -31 dB, and an IF return loss of -26 dB. The RF-IF isolation is -57 dB. Also, a conversion gain is 8.9 dB through output amplifier. The total on-chip down-converter is implanted in 2.56${\times}$1.07 mm$^2$ of chip area.

Optimal Snubber Design Strategy for the Resonant Inverter to Reduce RF Noise (공진형 인버터에 있어서 RF Noise 저감을 위한 Snubber 최적 회로 설계에 관한 연구)

  • Kim, Eun-Soo;Yoo, Dong-Wook;Oh, Sung-Chul;Lee, Jong-Moo
    • Proceedings of the KIEE Conference
    • /
    • 1990.11a
    • /
    • pp.380-383
    • /
    • 1990
  • When the MOSPET is applied as a switching device for the resonant inverter, a damped oscillating noise is appeared at specific frequency band. This damped Oscillation is caused by the series and parallel resonance due to distributed circuit parameter of snubber and main circuit. This paper describes the frequency-impedance characteristic of the resonant inverter and optimal snubber design strategy to reduce the RF noise.

  • PDF

Temperature Control for LED lamps using RF Communication (LED 조명 발열의 순차 제어시스템 연구)

  • Choi, Hyeng-Sik;Shin, Hee-Young;Oh, Ji-Youn;Lee, Sang-Seop
    • Proceedings of the Korean Society of Marine Engineers Conference
    • /
    • 2012.06a
    • /
    • pp.130-132
    • /
    • 2012
  • In this paper, a temperature control for LED(Light Emitting Diode) lamp using a cooling fan is studied. An efficient temperature control scheme for the LED lamp using the fan wind at the lowest sound noise is studied. For the study, after measurement of the minimum sound noise of the fan and related temperature of the LED lamp through tests, experiments on temperature control of the LED lamp using the fan with various size of heat sinks was performed. To minimize the fan sound noise, optimal size of the heat sink was studied. Also, a teleoperting control of LED lamps using RF communication was studied.

  • PDF