Inappropriate SRS Specifications

摘要

Because of SDOF filter bandwidth overlap, the capability of the SRS to perform pseudo-Fourier analysis is lost when f_r progression is linear. At analysis frequencies greater than 500 Hz, narrow-band energy detected in the time domain will be smeared across several f_r, and the resolving power will be sacrificed. It would be better to use the FFT. The lack of proper overlap at frequencies below 500 Hz will cause the loss of amplitude accuracy, which increases with decreasing frequency. Additionally, narrow-band resonance signals whose f_r is located midway between the 10-Hz-spaced filter frequencies will not be detected at all, even if they are high in amplitude. Proper attention must be paid to the specifications for SRS processing to prevent inaccurate results. The user industry has developed commonly accepted specifications for SRS over the years. These specifications are the result of academic analysis as well as practical experience and not intended to dissuade the reader from using SRS. SRS is the primary tool for accessing transient loads, an application that is not the province of the FFT. Properly done, the SRS is a powerful tool.