说明：  深入解析如何在matlab中正确使用fft,ifft函数，包括组合应用和参数特性,让你能将信号在时频域之间轻松自由地快速正确变换,同时根据需要调整变换的结果。提供两篇word测试和说明文档，通用化处理过的fft,ifft程序,和一个信号设计的应用实例，可以根据需要自行修改使用。
(Explaining thoroughly how to apply fft and ifft correctly in matlab,including the combination of application and parametric characteristic,so you can switch the signal between time domain and frequency domain easily, while according to the need to adjust the conversion results. Providing two test and description documents in word,fft and ifft programs in general formal, and an application examples for signal designing, which can be modified to put into use as needed.)