Soft dB Tenor 24bits Data User Guide - Manual (Page 32)

Tenor Data Logger Soft dB inc.
This parameter allows adjusting the overlap between
the time blocks used for the global levels historic
calculation. This parameter can be adjusted from 0%
to 90%. This parameter is used to increase the
number of blocks and the time resolution of the
historic graph. We suggest to keep this parameter to
0% if standard acoustic signals are used. A larger
overlap can be used to avoid aliasing problem when
the signal is impulsive.
The Export .txt function allows exporting the global historic data in text format.
5.2.2 Average FFT
This function computes the average power spectrum for the entire framework of the
selected channel. First, the time signal of the entire framework is divided into blocks of an
adjustable number of samples. The power spectrum is computed for each block and a
linear average is obtained. Also, the Average FFT module allows the overlap of the blocks
used for the average. For instance, the use of an overlap of 66% and the Hanning time
window is a classic set-up that compensates for data lost in the time window.
The interface of the Average FFT function is presented on the next figure.
Figure 23: Average FFT interface
User Manual p. 32