XN-8000 Frequently Asked Questions

Why do the results of power spectrum addition averaging differ between offline analysis and online analysis?

In online analysis, A/D conversion data is continuously updated even during a stop. When starting, data prior to the start point is also processed and averaged using FFT. In online analysis, FFT calculations are performed using past data plus new data corresponding to the overlap amount.

On the other hand, offline, there is no historical data, so we are using zero data plus the amount of overlap in the file data. As a result, the signal suddenly appears from zero, causing discrepancies in the lower frequency components.

Online Analysis

Offline analysis

Response Method

In the menu, go to Analysis > Analysis Conditions > Measurement, turn ON the delay time for the start condition (check the box), and set the time. The set time should be the duration of one frame of the time waveform (sample interval × data length).