• Title/Summary/Keyword: Tone spacing

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Analysis of Asymmetrical $IMD_3$ And ACPR Characteristics for pHEMT Power Amplifier (pHEMT 전력 증폭기의 $IMD_3$ 비대칭성과 ACPR 특성 해석)

  • Lee, Kang-Jun;Park, Chan-Hyuck;Koo, Kyung-Heon
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.221-224
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    • 2005
  • This paper discribes the nonlinear distortion of a pHEMT power amplifier. In the paper, we have used some commercially available power amplifiers for analyzing the relationship between the $IMD_3$ and ACPR for wireless LAN. And the $IMD_3$ results using two-tone test have been compared with ACPR to satisfy the requited 802.11g standard ACPR value. Measurement result shows that $IMD_3$ of 20MHz tone-spacing need to be more than 18.45dBc for power amplifiers. The WCDMA signal is fed into the power amplifier, for analyzing relationship between the asymmetrical $IMD_3$ and ACLR. With measurement result, the asymmetrical $IMD_3$ characteristic has increased with the increase of two-tone spacing. $IMD_3$ measurement result with maximum 20MHz of the two-tone spacing, shows that the difference between $IMD_3(lower)$ and $IMD_3(upper)$ is about 7dB. And the measured ACLR shows 5dB difference at -4MHz and +4MHz offset from center frequency.

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Effective Measurement and modeling of memory effects in Power Amplifier (RF 전력 증폭기 메모리 효과의 효율적인 측정과 모델링 기법)

  • Kim, Won-Ho;HwangBo, Hoon;Nah, Wan-Soo;Park, Cheon-Seok;Kim, Byung-Sung
    • Proceedings of the KIEE Conference
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    • 2004.11c
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    • pp.261-264
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    • 2004
  • In this paper, we identify the memory effect of high power(125W) laterally diffused metal oxide-semiconductor(LDMOS) RF Power Amplifier(PA) by two tone IMD measurement. We measure two tone IMD by changing the tone spacing and the power level. Different asymmetric IMD is founded at different center frequency measurements. We propose the Tapped Delay Line-Neural Network(TDNN) technique as the modeling method of LDMOS PA based on two tone IMD data. TDNN's modeling accuracy is highly reasonable compared to the memoryless adaptive modeling method.

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A Split-channel Two-tone OOK Scheme Considering IoT Communication System in Fading Channel (페이딩 채널에서 사물인터넷을 위한 split-channel two-tone OOk 기법)

  • Lee, Gun-ho;Lee, Eui-soo;Jeong, Eui-rim
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2019.05a
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    • pp.607-609
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    • 2019
  • The split-channel two-tone OOK method proposed in this paper can improve the communication performance of IoT in fading channel environment. The frequency diversity effect can be obtained by separating the interval of the two tone signals, and a performance gain of 8 dB can be obtained in the fading channel. In addition, by using split-channel, the problem of degradation of the channel bandwidth efficiency caused by the frequency diversity technique can be prevented, thereby reducing the bandwidth efficiency by allocating the remaining frequency channels to other users.

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NUMERICAL STUDY ON THE FREQUENCY CHARACTERISTICS OF SCREECH TONE IN A SUPERSONIC JET (초음속 제트의 스크리치 톤 주파수 특성에 관한 수치적 연구)

  • Kim, Yong-Seok;Ryu, Ki-Wahn;Hwang, Chang-Jeon;Lee, Duck-Joo
    • Journal of computational fluids engineering
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    • v.12 no.1
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    • pp.53-59
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    • 2007
  • An axisymmetric supersonic screeching jet is numerically simulated to examine the length scales of screech frequency as well as screech tone generation mechanism. The axisymmetric Reynolds-averaged Navier-Stokes equations in conjuction with a modified Spalart-Allmaras turbulence model are employed. It is demonstrated that the axisymmetric jet screech tones can be simulated correctly and the numerical results are in good agreement with the experimental data. Instability waves, shock-cell structures and the phenomena of shock motion are investigated in detail to identify the screech tone generation mechanism. Shock spacings and standing wave length are analyzed to determine the dominent length scale crucial to the screech frequency formulation.

Sound Characteristics and Performance of Even and Uneven Blade Spacing Helicopter Anti-Torque System (균등 및 비균등 배열 헬리콥터 반토오크 시스템 성능 및 소음특성)

  • Song, Keun-Woong;Chung, Ki-Hoon;Kang, Hee-Jung;Kim, Seung-Bum;Lee, Je-Dong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.8 s.113
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    • pp.857-863
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    • 2006
  • This paper described the performance test and sound characteristics of helicopter 'Tail-Fan' anti-torque system. In this research, Korea Aerospace Research Institute(KARI) developed 'Tail-Fan' anti-torque system for a helicopter and carried out performance and sound capturing tests of even and uneven tail fans. The performance test is carried out and the noise signals which are generated during the test are saved with microphones at the same time. The performance test's results meet the design requirements. Tone-corrected perceived noise level is reduced by replacing the even product with the uneven one.

A Research on the Magnitude/Phase Asymmetry Measurement Technique of the RF Power Amplifier Based on the Predistortive Tone Cancellation Technique

  • Choi, Heung-Jae;Shim, Sung-Un;Kim, Young-Gyu;Jeong, Yong-Chae;Kim, Chul-Dong
    • Journal of electromagnetic engineering and science
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    • v.10 no.2
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    • pp.73-77
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    • 2010
  • This paper proposes a novel memory effect measurement technique in RF power amplifiers(PAs) using a two-tone intermodulation distortion(IMD) signal with a very simple and intuitive algorithm. Based on the proposed predistortive tone cancellation technique, the proposed measurement method is capable of measuring the relative phase and magnitude of the third-order and fifth-order IMDs, as well as the fundamental signal. The measured relative phase between the higher and lower IMD signal for specific tone spacing can be interpreted as the group delay(GD) information of the IMD signal concerned. From the group delay analysis, we can conclude that an adaptive control of GD as well as the magnitude and phase is a key function in increasing the linearization bandwidth and the dynamic range in a predistortion(PD) technique.

New Analog Predistorter for Independent Control of IM3 Components (3차 상호변조왜곡성분의 독립적인 조절을 위한 새로운 전치왜곡기)

  • Lee, Yong-Sub;Lee, Mun-Woo;Jung, Sung-Woo;Jeong, Yoon-Ha
    • Proceedings of the IEEK Conference
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    • 2007.07a
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    • pp.159-160
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    • 2007
  • Two analog predsitorters (PDs) using the mixing operation are proposed to compensate for the memory effects of the power amplifier and then significantly cancel IM3 components with the independent control of IM3 terms. In the first PD, IM3 terms are generated by using mixing operation of low frequency terms. In the second PD, the double mixing operation of the fundamental components is used. For a two-tone signal with 20-MHz tone spacing, the notable IM3 suppression is achieved over a whole output power range.

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System Analysis for Receiving Performance Improvement of Mobile Station in PCS (개인휴대통신에서 이동국의 수신성능개선을 위한 시스템 분석)

  • Ju, Jae-Han;Park, Se-Seung;Park, Jong-An;Cheon, Jong-Hun
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.1
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    • pp.159-166
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    • 1999
  • In this paper, we examined noise figure and the 3rd order intercept point in sensitivity single tone desensitization, and response attenuation by intermodulation spurious of receiver and also analyzed them through simulation based on J-STD-0.18, which is the minimum specification of PCS mobile station. The result of simulation was as follows ; In sensitivity specification, the total noise figure was 5.99dB and the 3rd order intercept point was -33.979dB. Ins ingle tone desensitization and intermodulation spurious response attenuation specification, the total noise figure was 6.375dB and the 3rd order intercept point was -26.99dBm. When there is an interference tone, the nosie figure and the 3rd order intercept point have been increasedly 0.367dB respectively, compared wit that of no interference tone. Because the amount of increase in the 3rd order intercept point was highly raised more than that of noise figure, mixer, closely related to interference tone should be specified in high 3rd order intercept point. At a frequency spacing of 1.25MHz and 2.05MHz from center frequency in IF SAW filter, attenuation should be more than 45dB.

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Application of Feed-forward Linearization Method to A Transmitter System (Feed-forward 선형화 방식을 적용한 송신 시스템 설계)

  • 김경태;김상규
    • The Journal of the Acoustical Society of Korea
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    • v.23 no.4
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    • pp.303-308
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    • 2004
  • In this Paper a transmitter system for IMr-2000 using feed-forward linearization method was Proposed to linearize power amplifier. The feed-forward structure needs a reference signal to compare and neutralize distortion : this is achieved through the second modulator which is operated at very low input level to obtain a signal with a negligible distortion. Therefore, this structure can reduce distortion of modulator as well as Power amplifier. This is the advantage over the existing system structure. The Proposed transmitter system is designed and simulated by Agilent ADS ver.2002. A two tone test for the system is done at 1.98GHz center frequency with frequency spacing of 2MHz. The reduction of Inter-Modulation Distortion(IMD) is around 49.95dB. This proposed system offers an excellent combination of linearity and simplicity.

A Feedforward High Power Amplifier with Loops that can Reduce RX Band Noise as well as Intermodulation Distortion Signals (수신 대력 잡음과 혼변조 왜곡 신호 제거 루프를 갖는 Feedforward 대전력 증폭기 설계)

    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.12 no.2
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    • pp.308-315
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    • 2001
  • In this paper, a new power amplifier is proposed for reduction of amplified RX band noise signals as well as intermodulation distortion signals using feedforward technique. This power amplifier is implemented for IMT-2000 basestation TX frequency band. Both TX band intermodulation distortion signals and RX band noise signals are reduced by controlling variable attenuator, phase shifter and error amplifier. The proposed power amplifier, which contains two loops-intermodulation distortion signals cancellation loop and RX band noise signals cancellation loop, can provide duplexer with low TX path insertion loss for various wireless communication systems due to choice of loose RX attenuation characteristic. The principle of the proposed amplifier is described graphically based on the conceptual schematic diagram. A two-tone test for power amplifier is done at 2.14GHz with frequency spacing of 5MHz, and RX band rejection test is done over RX full band of 60MHz with 1.95GHz center frequency. Experimental results represent that the cancellation performance of intermodulation distortion signals and RX band noise signals are more than 3 1dB and 21dB, respectively.

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