线性调频Z变换在舱音背景声的特征频率分析中的应用

舱音背景声特征频率的确定是调查失事飞机事故原因的重要依据之一。基于舱音译码辨听和音频分析的传统方法难以准确获得舱音背景声的特征频率。本文提出采用基于FFT的线性Z变换(CZT)来获取舱音背景声的特征频率的新方法,该方法适用于高采样频率的信号,计算中可以调整频率的分辨率,增加了FFT和频谱分析的灵活性。通过仿真和对用舱音记录器测录的真实舱音背景声计算分析得出:CZT方法是一种适合于确定舱音背景声特征频率的实用、有效方法,用以区分不同舱音在频率上的差别,满足飞机事故原因调查的需要。

Application of CZT algorithm to characteristic frequency analysis in the background sound recorded by CVR

Characteristic frequency of the background sound recorded by a Cockpit Voice Recorder(CVR)is a key evidence in investigating accident causes for a wrecked airplane. It is difficult to obtain exact characteristic frequency with the aid of traditional methods of differentiating & hearing by cockpit voice decoding system(CVDS)and of the frequency analysis by the audio software.A new method of obtaining characteristic frequency is im- posed in this paper based on the Chirp Z Transform(CZT),because the method is suitable for high sampling frequency and possessed with high flexibility of adjusting the frequency resolution & spectrum analysis.On simulation and calculation for a real background sound recorded by CVR from an airplane,it can be concluded that it is a feasible method to de- termine the characteristic frequency.