声表面波式小波变换阵列器件频带连续性的研究

Study on Frequency Band Continuity for Surface Acoustic Waves’ Wavelets Transform Array Device

针对声表面波式小波变换阵列器件频带不连续或重叠的问题 ,在尺度二进离散基础上 ,对基波中心频率和基波频宽半径在不同关系下对频带覆盖因子的影响进行了研究 ,提出基波中心频率等于 3倍基波频宽半径 ,声表面波式小波变换阵列器件实现频带连续且频带覆盖因子等于 10 0 %的设计方案 .根据这种方案设计的声表面波式小波变换阵列器件 ,不仅在 - 3dB处实现了频带的完全连续 ,解决了选择基波中心频率大于或小于 3倍基波频宽半径时频带不连续而造成分析信号漏检和必须使用大量器件来实现不必要重叠频带的问题 ,而且使阵列器件的变换尺度、中心频率。

To select incorrect fundamental center frequency may cause the discontinuation or overlap of the frequency band for surface acoustic waves' wavelets transform array device, based on scale dyadic dilation, the relationship between fundamental center frequency and frequency band radius that affects the coverage factor of frequency band was studied. A novel design scheme was brought forward. The fundamental center frequency is defined to be three times of radius of the fundamental frequency band, which assures that the frequency band of surface acoustic waves' wavelets transform array device is continuous, and that the coverage factor of frequency band is equal to 100%. The surface acoustic waves' wavelets transform array device produced with this design scheme can make the frequency band continuous exactly. Therefore, this design scheme can prevent from losing signals caused by the discontinuation of frequency band and wasting devices caused by the overlap of frequency band. Furthermore, the one-to-one mapping relation among transform scale, center frequency and radius of the fundamental frequency band is established. The experiments of surface acoustic waves' wavelets transform array device indicate that frequency bands are continuous without overlap.