NONSTATIONARY QUIVER SPINDLE BACKGROUND

SOUND ANALYSIS OF AIRPLANE VIA

WIGNER-VILLE AND WAVELET

TIME-SCALE DISTRIBUTION

CHENG Daolai¹  YI Chuijie¹  GUO Jianxiang¹  YAO Hongyu²  YANG Lin²  ZHONG Minzhu²

(1. Qingdao R&D Center of Energy and Environmental Equipment, Qingdao Technological University, Qingdao 266033;
2. Center of Aviation Safety Technology, General Civil Aviation Administration of China, Beijing 100028)

Abstract: Cockpit voice recorder (CVR) in aircraft black box records many cockpit voices, such as speaker voices, noises, special meaning background sounds. Cockpit voices’ complexity exacerbates analysis difficulty through traditional differentiating & hearing methods. These methods’ key techniques puzzles such as cockpit voices’ characteristics identification are not resolved. According to the shortage in cockpit voice hearing and analyses by traditional Fourier transformation(FT) single time/frequency and short time Fourier transformation (STFT) double energy, the new methods ,which can applied to analysis of no stationary cockpit background sound, is set up by means of introducing Wigner-Ville time-frequency and wavelet time-scale technology respectively into airplane cockpit voice analyses, as an example of quiver spindle background sound recorded by CVR. Compared with these methods, it is demonstrated that the spectrogram of both smooth pseudo Wigner-Ville distribution(SPWVD) and its time-frequency re-distribution features high time-frequency resolution, immunity of cross term interference; and that the resonate frequency and response time are obtained by time-scale analysis of discrete wavelet transformation(DWT) .

Key words: Wigner-Ville distribution (WVD) Wavelet transformation(WT) Cockpit voice recorder(CVR) Quiver spindle background sound Non-staticnary signal Time-frequency analysis Time-scale analysis

CLC No: TB533⁺.2 V328.1

国家自然科学基金(60572182)和中国民航总局科技基金(05-10-A)资助项目. Received 20060620, received in revised form 20070115