An array extension method in a noisy environment was proposed to improve angular resolution and array gain. The proposed method combines the FOC （fourth-order cumulants） technique with the ETAM （extended towed arra...An array extension method in a noisy environment was proposed to improve angular resolution and array gain. The proposed method combines the FOC （fourth-order cumulants） technique with the ETAM （extended towed array measurements） method to extend array aperture and suppress Gaussian noise, First, successive measurements of a virtual uniform linear array were constructed by applying lburth-order cumulants to measurements of uniform linear array; Gaussian noise in these measurements was also eliminated. Then, the array was extended by compensating phase differences using the ETAM method, Finally, the synthetic aperture was extended further by the fourth-order cumulants technique. The proposed FOC-ETAM-FOC method not only improves angular resolution and array gain, but also effectively suppresses Gaussian noise. Furthermore, it inherits the advantages of the ETAM method. Simulation results showed that the FOC-ETAM-FOC method achieved better angular resolution and array gain than the ETAM method. Furthermore this method outperforms the ETAM method in Gaussian noise environment.展开更多
In this paper,single-point field measurements of noise radiated from high-speed trains were performed at two sites along Beijing-Tianjin intercity railway(BTIR),aiming at acquiring the realistic acoustic data for vali...In this paper,single-point field measurements of noise radiated from high-speed trains were performed at two sites along Beijing-Tianjin intercity railway(BTIR),aiming at acquiring the realistic acoustic data for validation and verification of physical model and computational prediction.The measurements showed that A-weighted sound pressure levels(SPLs) were between 80 and 87 dBA as trains passed.The maximum noise occurred at the moment when the pantograph arrived,suggesting that pantograph noise was one of the most significant sources.Sound radiated from high-speed trains of BTIR was a typical broadband spectrum with most acoustic power restricted in the range of medium-high frequency from about 400 Hz to 5 kHz.Aerodynamic noise was shown to be the dominant one over other acoustic sources for high-speed trains.展开更多
基金Supported by the National Science Foundation of China (No.60872146)
文摘An array extension method in a noisy environment was proposed to improve angular resolution and array gain. The proposed method combines the FOC （fourth-order cumulants） technique with the ETAM （extended towed array measurements） method to extend array aperture and suppress Gaussian noise, First, successive measurements of a virtual uniform linear array were constructed by applying lburth-order cumulants to measurements of uniform linear array; Gaussian noise in these measurements was also eliminated. Then, the array was extended by compensating phase differences using the ETAM method, Finally, the synthetic aperture was extended further by the fourth-order cumulants technique. The proposed FOC-ETAM-FOC method not only improves angular resolution and array gain, but also effectively suppresses Gaussian noise. Furthermore, it inherits the advantages of the ETAM method. Simulation results showed that the FOC-ETAM-FOC method achieved better angular resolution and array gain than the ETAM method. Furthermore this method outperforms the ETAM method in Gaussian noise environment.
基金supported by the National Key Technology R&D Program (Grant No.2009BAG12A03)Knowledge Innovation Project of Chinese Academy of Sciences of China(Grant No.KJCX2-EW-L02-1)
文摘In this paper,single-point field measurements of noise radiated from high-speed trains were performed at two sites along Beijing-Tianjin intercity railway(BTIR),aiming at acquiring the realistic acoustic data for validation and verification of physical model and computational prediction.The measurements showed that A-weighted sound pressure levels(SPLs) were between 80 and 87 dBA as trains passed.The maximum noise occurred at the moment when the pantograph arrived,suggesting that pantograph noise was one of the most significant sources.Sound radiated from high-speed trains of BTIR was a typical broadband spectrum with most acoustic power restricted in the range of medium-high frequency from about 400 Hz to 5 kHz.Aerodynamic noise was shown to be the dominant one over other acoustic sources for high-speed trains.
