Suppression of Cavity Time-Delay Signature Using Noise-Phase-Modulated Feedback

Han, Hong; Cheng, Xu Min; Jia, Zhi Wei; Shore, K.A.

doi:10.1109/access.2020.2975359

Cited by 4 publications

(4 citation statements)

References 23 publications

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“…The maximum TL obtained in the simulation is approximately 24.6 dB, and most of the transmission loss peaks occur between 15 dB and 25 dB. The main reason for the difference between the measured and simulated TL results is that it is difficult to simulate the acoustic process sufficiently accurately due to the nonlinearity of the materials used in elastic membranes [22].…”

Section: Testing and Verification A Comparison Of Simulation Resultsmentioning

confidence: 94%

Noise Reduction in Tractor Cabs Using Coupled Resonance Acoustic Materials

et al. 2022

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The noise level in a tractor cab directly affects the driving experience. Reducing the noise level in a tractor cab is an important means of improving the image of the product brand and protecting the physical and psychological health of employees. To reduce medium-and low-frequency noise in a tractor cab, the influence of the installation of coupled resonance acoustic materials (CRAMs) on tractor driver ear noise is investigated in this study. Theories for sound absorption by perforated plates and sound insulation by thin membranes are used to design a CRAM composed of a perforated plate, elastic membrane and additional mass. The acoustic impedance and sound absorption coefficient of the CRAM are obtained by an equivalent circuit method, and the resonance frequency of a local resonance system composed of an elastic membrane and additional mass is calculated. The effects of different hole diameters and porosities of the perforated plate on the CRAM sound absorption coefficient are compared. The results of tests performed using impedance tubes over a wide frequency range of 50 Hz∼1600 Hz show that the maximum sound absorption coefficient is 0.99 and several transmission loss peaks of 15 dB∼26 dB. Measurement of the acoustic response of the CRAM installed on the cab front panel shows that an ear noise reduction of approximately 1.3 dB(A) for a tractor working speed of 2200 rpm. The results show that the designed CRAM has a relatively good effect on reducing driver ear noise over a wide frequency band and is a feasible scheme for noise reduction in a tractor cab.INDEX TERMS Coupled resonance acoustic material (CRAM), tractor, noise reduction.

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Section: Testing and Verification A Comparison Of Simulation Resultsmentioning

confidence: 94%

Noise Reduction in Tractor Cabs Using Coupled Resonance Acoustic Materials

et al. 2022

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“…In our scheme of injection into optical time lens with noise phase modulation, it is expectable that the chaotic output signal performs better than that from conventional optical feedback in terms of TDS characteristics because of the stochastic nature of the ASE noise signal [32]. Through numerical investigations, it was noticed that the dispersive fiber coefficients did not play an obvious role according to the variation of the TDS of the chaotic output signal.…”

Section: Time-delay Signature Characteristics Of the Generated Chaosmentioning

confidence: 95%

Wideband Millimeter-Wave Flat Chaos Generation With Controllable Power Spectrum Using Optical Time Lens

Zinsou

Gao

et al. 2021

IEEE Photonics J.

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We propose and numerically demonstrate the generation of wideband millimeter-wave (mmW) flat chaos with controllable power spectrum by injection of chaotic signal from external cavity semiconductor laser (ECSL) into optical time lens with noise phase modulation. Simulation results indicate consistent elimination of the ECSL relaxation oscillation frequency domination over the RF spectrum for large scale parameters of the optical time lens module and a wideband flat chaos, whose efficient bandwidth rapidly increases with the bandwidth of the noise signal driving the phase modulator and phase modulation index. Besides, we show that the time delay signature suppression can be concurrently achieved for moderate values of the noise bandwidth and phase modulation index. The proposed wideband mmW flat chaos exhibits great potential applications for ultrahigh-speed chaos communications, mmW radars and macroscopic mmW noise source required for mmW research and design.

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“…However, the suppression of phase noise that changes rapidly over time due to rapid changes in the target surface is not satisfactory. The second study is on the suppression of phase noise in the laser itself [30][31][32][33][34], which is also unsatisfactory for photon-level weak target echoes and the lack of prior information on target surface changes. This is because the effect of phase noise on the detected photocurrent data in the conventional LHD method manifests itself as a multiplicative noise.…”

Section: While For the Case Ofmentioning

confidence: 99%

Laser Heterodyne Detection Based on Photon Time–Domain Differential Detection Avoiding the Effect of Decoherence Phase Noise

Guan,

Zhang,

Jia

et al. 2023

Sensors

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Laser heterodyne detection (LHD) is a key velocimetry technique that provides better accuracy and sensitivity than direct laser detection. However, random phase noise can be introduced by the surface topography of the moving target undulation or atmospheric turbulence during transmission. The random phase noise causes the target echo to undergo decoherence, resulting in degradation of the signal-to-noise ratio (SNR). Here, we propose a novel LHD method based on photon time–domain differential detection. It can infer the heterodyne spectrum of the target echo and the local oscillator light from the time intervals of the photon arrival. The time interval statistic is a relative quantity, which can effectively avoid the effect of random phase noise in LHD. With our method, the SNR of LHD can be improved in application scenarios where the target echo is decoherent. We developed a complete solution model for acquiring the heterodyne spectrum based on photon time–domain differential detection and performed proof-of-principle experiments. The experimental results show that in the presence of random phase noise, the SNR and velocity measurement error of our method are significantly better than that of the conventional method, and the larger the phase noise is, the more the SNR and velocity measurement error of our method are improved. Moreover, along with the increase in phase noise, the SNR of our method is basically unchanged, which also indicates that our method is not affected by random phase noise. This advantage is significant for photon-level weak echoes that require long detection times to be detected.

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Suppression of Cavity Time-Delay Signature Using Noise-Phase-Modulated Feedback

Cited by 4 publications

References 23 publications

Noise Reduction in Tractor Cabs Using Coupled Resonance Acoustic Materials

Noise Reduction in Tractor Cabs Using Coupled Resonance Acoustic Materials

Wideband Millimeter-Wave Flat Chaos Generation With Controllable Power Spectrum Using Optical Time Lens

Laser Heterodyne Detection Based on Photon Time–Domain Differential Detection Avoiding the Effect of Decoherence Phase Noise

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