• Title/Summary/Keyword: quadrature detection

Search Result 70, Processing Time 0.023 seconds

Analysis of Communication Performance According to Detection Sequence of MMSE Soft Decision Interference Cancellation Scheme for MIMO System (다중 입출력 시스템 MMSE 연판정 간섭 제거 기법의 검출 순서에 따른 통신 성능 분석)

  • Lee, Hee-Kwon;Kim, Deok-Chan;Kim, Tae-Hyeong;Kim, Yong-Kab
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
    • /
    • v.12 no.6
    • /
    • pp.636-642
    • /
    • 2019
  • In this paper, we analyzed BER (Bit Error Rate) communication performance according to the detection order of MMSE (Minimum Mean Square Error) based soft decision interference cancellation. As the detection order method, antenna index order method, absolute value magnitude order method of channel elements, absolute value sum order method of channel elements, and SNR (Signal Noise Ratio) order method are proposed. BER performance for the scheme was measured and analyzed. As a simulation environment, 16-QAM (Quadrature Amplitude Modulation) modulation is used in an uncoded environment of an M×M multiple-input multiple-output system, and an independent Rayleigh attenuation channel is considered. The simulation results show that the performance gain is about 1.5dB when the SNR-based detection order method is M=4, and the performance gain is about 3.5dB when M=8 and about 3.5dB when M=16. The more BER performance was confirmed, the more the detection order method of the received signal prevented the interference and error spreading occurring in the detection process.

A Study on the Development of CW(Continuous-Wave)Doppler System for measuring Bi-directional Blood Flow Information (혈류 방향을 구별하는 연속 초음파 도플러 장치에 관한 연구)

  • 강충신;김영길
    • Journal of Biomedical Engineering Research
    • /
    • v.8 no.1
    • /
    • pp.75-80
    • /
    • 1987
  • With the conventional CW Doppler velocity meter, bl-directional velocities cannot be separated. The new CW Doppler system uses quadrature detection and phase rotation to produce simultaneous independent audio and velocity signals for forward and reverse blood flow direction, is fabricated. Specially, this system shows that phase rotation method for flow direction separation provides easy and satisfactory feature. From in vivo blood flow measurement, we can easily differentiate typical artery flow from vein flow, and measure both velocity characteristics qualitatively.

  • PDF

New Evaluation on Maximum Ratio Diversity Reception for the Detection of Signals over Correlated Nakagami Fading Channels

  • Hong Wan-Pyo;Kim Chang-Hwan
    • Journal of information and communication convergence engineering
    • /
    • v.2 no.3
    • /
    • pp.145-148
    • /
    • 2004
  • The performances of M-ary signals using L-branch maximum ratio combining (MRC) diversity reception in correlated Nakagami fading channels are derived theoretically. The coherent reception of M-ary differential phase shift keying (MDPSK), phase shift keying (MPSK), and quadrature amplitude modulation (MQAM) is considered. It is assumed that the fading parameters in each diversity branch are identical. The general formula for evaluating symbol error rate (SER) of M-ary signals in the independent branch diversity system is presented using the integral-form expressions.

Transmission Performance Comparison of Direction Detection-Based 100-Gb/s Modulation Formats for Metro Area Optical Networks

  • Chung, Hwan Seok;Chang, Sun Hyok;Lee, Jonghyun;Kim, Kwangjoon
    • ETRI Journal
    • /
    • v.34 no.6
    • /
    • pp.800-806
    • /
    • 2012
  • Transmission performances of direct detection-based 100-Gb/s modulation formats are investigated and compared for metro area optical networks. The effects of optical signal-to-noise ratio sensitivity, chromatic dispersion, cross-channel nonlinearity, and transmission distance on the performance of differential 8-ary phase-shift keying (D8PSK), differential phase-shift keying plus three-level amplitude-shift keying (DPSK+3ASK), and dual-carrier differential quaternary phase-shift keying (DC-DQPSK) are evaluated. The performance of coherent dual-polarization quadrature phase-shift keying (DP-QPSK) with block phase estimation and coherent DP-QPSK with digital differential detection are also presented for reference. According to our analysis, all three direct detection modulation formats could transmit a 100-Gb/s signal over several hundred kilometers of a single-mode fiber link. The results also show that DC-DQPSK outperforms D8PSK and DPSK+3ASK, and the performance of DC-DQPSK is comparable to that of coherent DP-QPSK with digital differential detection. The maximum transmission distance of DC-DQPSK is over 1,000 km, which is enough distance for metro applications.

A Detection Method for An OFDM Signal Distorted by I/Q Imbalance (I/Q 불균형에 의하여 왜곡된 OFDM 신호의 검출방식)

  • Park Kyung-won;Cho Yong-soo
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.30 no.1A
    • /
    • pp.37-45
    • /
    • 2005
  • In this paper, after analyzing the effect of I/Q imbalance in an OFDM system, the detection method of an OFDM signal distorted by I/Q imbalance is proposed. Also, the channel estimation and the pilot symbol design scheme are proposed for using the proposed detection method. Since I/Q imbalance in an OFDM system degrades the SIR and the BER(Bit Error Ratio) performance, the robust detection method is required for an OFDM system. the proposed detection method can effectively suppress the interference caused by I/Q imbalance using characteristics of an OFDM signal differently from the conventional method, and results in improving the SIR of a desired OFDM signal.

Noise Cancellation and Detection of Heartbeat using A New Adaptive Noise Canceller Based on ALE(Adaptive Line Enhancer) in the CW Bio-radar (CW 바이오 레이더에서 ALE(Adaptive Line Enhancer) 기반의 새로운 적응형 잡음제거기를 이용한 잡음제거 및 심장박동 검출)

  • Seo, Myung-Hwan;Kim, Jae-Joong
    • Journal of Advanced Navigation Technology
    • /
    • v.13 no.4
    • /
    • pp.482-489
    • /
    • 2009
  • This paper proposes a CW(Continuous-Wave) bio-radar applying a new adaptive noise canceller based on ALE(Adaptive Line Enhancer) which can remove the Gaussian noise and system noise. Recently the research works on this CW bio-radar which can be used to detect heartbeat and respiration are advanced by the university and research facility. Although the researches describe CW bio-radar not only is vulnerable for the Gaussian noise but also has a disadvantage of decreasing the heart-rate accuracy due to the noise, the researches do not demonstrate the effective method for removing the noise component in a baseband signal. In this paper, a CW bio-radar applying the new adaptive noise canceller based on ALE which can remove the noise component is proposed. This paper compares and analyzes the performance for increasing the heart-rate accuracy according to removing the Gaussian noise and system noise in the baseband signal through the quadrature receiver which can alleviate the demodulation sensitivity to target position.

  • PDF

Detection of Elastic Waves Using Stabilized Michelson Interferometer (광로차 보상회로가 부착된 마이켈슨 간섭계에 의한 탄성파 신호검출)

  • Kim, Y.H.;So, C.H.;Kwon, O.Y.
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.13 no.4
    • /
    • pp.32-41
    • /
    • 1994
  • The stabilized Michelson interferometer was developed in order to measure micro dynamic displacement at the surface of solids due to elastic wave propagation. The stabilizer was designed to compensate light path disturbances using a reference mirror driven by piezoelectric actuator. Using stabilizer, the effect of external vibration was reduced and the quadrature condition was satisifed. As the results, the output of photodetector had maximum sensitivity and linearity. The minimum detectable displacement was 0.3nm at the band width of 10 MHz. The epicentral displacements due to the glass capillary breaks and the steel ball drop impact were measured using the developed interferometer and the results were compared with the calculated one.

  • PDF

A study on the implementation simulation and system for 2-D doppler system using second-order sampling (2차 샘플링을 이용한 2-D 도플러 시스템의 시뮬레이션과 시스템구현에 관한 연구)

  • 임춘성;임용곤
    • Journal of Biomedical Engineering Research
    • /
    • v.11 no.1
    • /
    • pp.147-156
    • /
    • 1990
  • A two-dimensional pulsed doppler system for ultrasonic blood velocity doppler signals is studied and implemented. The second-order sampling method and serial data processing procedures are utillized in the sys- tem, which eliminates the untuning problems at phase channels in the quadrature detection method as well as in the channels of parallel data processing. rho digital signal processor used in this system allows a hardware savings and flexible design options. The efficiency of the various mean frequency estimators in the second-order sampling system is examined by computer simulation as a function of the intersequence sample delay time. The temporal delay for the quadrature component is changed from $1/(4f_o){\;}to{\;}3/(4f_o){\;}and{\;}5/(4f_o)$ where to is the center frequency of the transducer, It is found that autocorrelator is the optimum frequency estimator for the second-order sampling: with !he intersequence sample delay of $1/(4f_o){\;}to{\;}3/(4f_o){\;}and{\;}5/(4f_o)$. The qualitative variation and information proportional to blood velocity in the vessel system are obtained in the VIVO experiments.

  • PDF

Coded Layered Space-Time Transmission with Signal Space Diversity in OFDM Systems (신호 공간 다이버시티 기법을 이용한 OFDM 기반의 부호화된 시공간 전송기법)

  • Kim, Ji-Hoon;Lee, In-Kyu
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.32 no.7C
    • /
    • pp.644-651
    • /
    • 2007
  • In multiple antenna systems, vertical Bell Labs Layered Space-Time (V-BLAST) systems enable very high throughput by nulling and cancelling at each layer detection. In this paper, we propose a V-BLAST system which combines with signal space diversity technique. The benefit of the signal space diversity is that we can obtain an additional gain without extra bandwidth and power expansion by applying inphase/quadrature interleaving and the constellation rotation. Through simulation results, it is shown that the performance of the proposed system is less than 0.5dB away from the ideal upper bound.

A Study on A New Two-Dimensional Pulsed Doppler System Using Second-Order Sampling Method. (2차 샘플링을 이용한 새로운 초음파 2차원 펄스 도플러 시스템에 관한 연구)

  • Park, Se-Hyeon;Im, Chun-Seong;Kim, Yeong-Gil
    • Journal of Biomedical Engineering Research
    • /
    • v.10 no.1
    • /
    • pp.33-42
    • /
    • 1989
  • The doppler effect is used for measuring the velocity of the blood flow in artery. Because of the range information, the pulsed doppler system is most commonly used. In this paper, we propose a new two-dimensional(2-D) pulsed Doppler system. Which uses second-order sampling method and serial processing. The proposed system using second-order sampling method eliminates in-phase, quadrature-phase balancing problem at demodulator of quadrature detection method. In addition, the new pulsed 2-D doppler system eliminates balancing problem of channels of 2-D doppler system because of serial processing.

  • PDF