• Title/Summary/Keyword: Chirp Signal

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Implementation of 40kbps Narrowband Powerline Communication Modem using Chirp Spread Spectrum Method (Chirp 대역확산방식을 이용한 40kbps급 협대역 전력선 통신 모뎀 구현)

  • Lee Won-Tae;Woo Dae-Ho;Yu Young-Gyu;Lee Young-Chul
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.54 no.2
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    • pp.116-123
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    • 2005
  • Chirp spread spectrum method using both time and frequency component is fit to time varying channel such as powerline channel. The used chirp symbol based on the CEBus standard is the unit symbol which sweeps from 100kHz to 380kHz over a 25㎲. To evaluate the performance of between Chirp-SS and DSSS, we measured the bit error rate under Gaussian channel. Simulation result is shown that Chirp-SS has a about 3[dB] gain of SNR than DSSS. To verify the performance of implemented modem, it is made up the powerline channel environment. After adding several noises to it, we examined the receiving status of modem. The implemented modem is able to receive the signal over the powerline channel with having several noises and capacitive loads.

UWB Communication and Ranging System using Frequency Slope Modulated Chirp (주파수 효율 및 성능 향상을 위한 Frequency Slope Modulated Chirp 신호를 이용한 UWB 시스템)

  • Kim, Jung-Hyun;Kim, Ji-Hyun;You, Cheol-woo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.2A
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    • pp.127-132
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    • 2011
  • This paper proposes a ranging and communicating system that uses the UWB frequency slope modulated chirp signal. Instead of using only the up-chirp and down-chirp with the same frequency sweeping rate, the proposed system uses several chirps that have different frequency sweeping rates with frequency hopping. This system performs better than the conventional communication and ranging schemes because it is capable of increasing the data transmission rate and at the same time decreasing the interference between sequences used by users. In this paper, we propose simulations of UWB communication system to show validity by using the MATLAB.

Transform Domain Adaptive Filtering with a Chirp Discrete Cosine Transform LMS (CDCTLMS를 이용한 변환평면 적응 필터링)

  • Jeon, Chang-Ik;Yeo, Song-Phil;Chun, Kwang-Seok;Lee, Jin;Kim, Sung-Hwan
    • The Journal of the Acoustical Society of Korea
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    • v.19 no.8
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    • pp.54-62
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    • 2000
  • Adaptive filtering method is one of signal processing area which is frequently used in the case of statistical characteristic change in time-varing situation. The performance of adaptive filter is usually evaluated with complexity of its structure, convergence speed and misadjustment. The structure of adaptive filter must be simple and its speed of adaptation must be fast for real-time implementation. In this paper, we propose chirp discrete cosine transform (CDCT), which has the characteristics of CZT (chrip z-transform) and DCT (discrete cosine transform), and then CDCTLMS (chirp discrete cosine transform LMS) using the above mentioned algorithm for the improvement of its speed of adaptation. Using loaming curve, we prove that the proposed method is superior to the conventional US (normalized LMS) algorithm and DCTLMS (discrete cosine transform LMS) algorithm. Also, we show the real application for the ultrasonic signal processing.

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A Receiver Architecture with Low Complexity for Chirp Spread Spectrum in IEEE 802.15.4a (IEEE 802.15.4a Chirp SpreadSpectrum을 위한 저복잡도 수신기 구조)

  • Kim, Yeong-Sam;Chong, Jong-Wha
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.47 no.8
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    • pp.24-31
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    • 2010
  • A receiver architecture with low complexity for chirp spread spectrum (CSS) of IEEE 802.15.4a is proposed. To demodulate the received signal at the highest signal to noise power ratio, matched filter is generally adopted for the receiver of wireless communication systems. It is, however, not resonable to adjust the matched filter to the receiver of CSS whose objectives are low complexity, low cost and low power consumption since complexity of the matched filter is high. In this paper, we propose a new receiver architecture using differential multiplication and accumulator not matched filter for demodulation. Also, bi-orthogonal decoder implemented by only adder/subtractor is proposed. The hardware resources for implementation are reduced in the proposed receiver architecture, although bit error rate performance is low compared with the receiver architecture based on the matched filter.

Communication Cable Fault Localization Based on Chirp Signal Parameter Estimation (첩 신호 파라메터 추정 기반 통신 케이블 고장점 탐지에 관한 연구)

  • Lee, Chun-Ku;Han, Seul-Gi;Park, Jin-Bae;Yoon, Tae-Sung
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.1782_1783
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    • 2009
  • Reflectometry that has been used to localize faults on a cable is introduced. One of the key point of reflectometry is finding time delay between the incident and reflected signals. In this paper, we propose new reflectometry that use Gaussian enveloped linear chirp signal, and use Kalman filter to estimate frequency rate parameter of the chirp signal. From the estimated frequency rate parameter, we can measure the time delay. In a simulation assuming open ended cable, the proposed method is proved to give a good estimation results.

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Improvement of Power Spectrum in Ultrashort Pulse Reflectometry Signals Using Three Chirp Configuration

  • Roh, Young-Su
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.28 no.3
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    • pp.51-56
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    • 2014
  • The flat power spectrum of the transmitter output signal for the desired frequency range is ideal to achieve the best performance of ultrashort pulse reflectometry. However, the power spectrum of a typical pulse generator decreases significantly as frequency increases. A configuration of three chirped waveforms was employed to improve the power spectrum of the transmitter signal at higher frequencies. To determine the amplification gain required for higher frequency components, three chirped waveforms were theoretically generated and their power spectra were measured using numerical band-pass filters. Based on the results of numerical computations, the three chirp configuration was successfully applied to the design of the transmitter for a broadband system.

Minimization of power penalty using chirp parameter for 2.5 Gbps, 8 channel, 400 km optical link system with dispersion and SPM (분산과 SPM이 존재하는 2.5Gbps, 8채널 400km 광 링크 시스템에서의 처핑 계수를 이용한 수신 감도 저하의 최소화)

  • 이병호;박영일;김익상;채창준;이병호
    • Korean Journal of Optics and Photonics
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    • v.8 no.3
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    • pp.250-253
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    • 1997
  • The effect of dispersion in optical transmission system changes according to chirp and SPM. Chirp depends on the modulation condition of an external modulator. SPM is proportional to signal power. In this paper, we analyzed the pulse broadening due to SPM and chirp in the system with dispersion by using Split Step Fourier Method and calculated the optimum chirp parameter for 400 km transmission system. Experimental results are presented also.

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Instantaneous Frequency Estimation of the Gaussian Enveloped Linear Chirp Signal for Localizing the Faults of the Instrumental Cable in Nuclear Power Plant (가우시안 포락선 선형 첩 신호의 순시 주파수 추정을 통한 원전 내 계측 케이블의 고장점 진단 연구)

  • Lee, Chun Ku;Park, Jin Bae;Yoon, Tae Sung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.7
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    • pp.987-993
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    • 2013
  • Integrity of the control and instrumental cables in nuclear power plant is important to maintain the stability of the nuclear power plants. In order to diagnose the integrity of the cables, the diagnostic methods based on reflectometry have been studied. The reflectometry is a non-destructive method and it is applicable to diagnose the live cables. We introduce a Gaussian enveloped linear chirp reflectometry to diagnose the cables in the nuclear power plants. In this paper, we estimate the instantaneous frequency of the Gaussian enveloped linear chirp signal by using the weighted robust least squares filtering to localize the impedance discontinuities in the class 1E instrumental cable.

Overlap-Based Chirp Spread Spectrum Transmission Scheme for Maritime Multipath Environment (해양 다중 경로 환경에 알맞은 오버랩 기반 처프 확산 대역 전송 기법)

  • Chae, Keunhong;Lee, Seong Ro;Yoon, Seokho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39C no.11
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    • pp.1124-1131
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    • 2014
  • The chirp spread spectrum (CSS) technique that transmits data signal by using a chirp signal is often used for maritime wireless communication systems such as sound detection radar systems for submarines. However, maritime multipath environment could reduce the data rate of the CSS system. To tackle the problem, an overlap-based CSS transmission scheme is proposed and analyzed in this paper: Based on the approximated Gaussian Q function, we derive a closed form expression of the bit error rate (BER) of the proposed overlap-based CSS system and investigate the mathematical relationship between the number of overlaps and the intersymbol interference (ISI).

Effective Compensation of Distorted WDM Signals Related with Frequency Chirp (주파수 �V이 다른 WDM 신호의 효율적 왜곡 보상)

  • Lee, Seong-Real;Yim, Hwang-Bin
    • Journal of Advanced Navigation Technology
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    • v.11 no.4
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    • pp.394-400
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    • 2007
  • We induced the optimal values of optical phase conjugator (OPC) position and dispersion coefficients of fiber sections depending on frequency chirp, which is substantially generated in optical signal by optical modulator and affects the transmission performances. In order to investigate the relation of optimal parameters with various frequency chirp, in this paper, positive(down) chirp, chirp-free and positive(up) chirp are assumed in 40 Gbps ${\times}$ 16 channels WDM transmission system of NRZ format with extinction ratio of 10 dB, which are the worst system parameters in the factor affecting system performance. It is confirmed that the OPC position offset and dispersion offsets between both fiber sections are more increased as frequency chirp become larger. It is also confirmed that the effect of the induced values on the compensation of WDM channels with negative frequency chirp is better than WDM channels with positive frequency chirp.

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