文章介绍了在带限频带下双阈值频谱检测的情况，并给出仿真结果。-This paper introduces the band in the band-limited frequency spectrum under the dual-threshold detection of the situation and give the simulation results.

滚动轴承故障诊断是机械故障检测中一个重要方面。使用小波包分析和包络分析相结合的方法提取轴承微弱振动信号, 克服了传统包络分析方法易丢失信号有效成分的缺点。包络信号的细化谱较好体现了轴承故障信息。-Bearing Fault Diagnosis of mechanical fault detection in an important aspect. The use of wavelet packet analysis and envelope analysis method of combini