cztdetectfrequency

代码说明：

  用于一般访求不能达到分辨率的频率检测方法，可以高精度检测频率。尤其是对于分辨率达不到要求的时候，用此方法能达到很高的分辨率。对有用频段的频率进行高分辨率的细化。(Usually visit requirements can not achieve the resolution of the frequency detection methods, and can be detected with high precision frequency. Especially for the resolution of failing to meet required when using this method can achieve high resolution. Useful frequency band high-resolution refinement.)