Soft dB Tenor 24bits Data User Guide - Manual (Page 27)

Tenor Data Logger Soft dB inc.
Peak and time signal graphs
The approach used by the post-processing module allows the analysis of a large wave file
(the wave standard allows a maximum size of 2GB for a wave file: about 3.0 hours at 48.8
kHz). The use of a streaming approach solves the memory limitation problem met when a
large wave file is used. This means that the whole signal contained in the wave file is
never completely loaded in the PC’s memory. The post-processing always reads the signal
block-by-block. With this streaming technique, the memory requirement problem is solved
but the user loses the overview of the entire signal contained in the wave file. To resolve
this problem, the post-processing interface presents the peak values of the entire wave
file. The peak value curve always contains 8192 points. This means that the entire signal
is divided in 8192 blocks and the peak values of each block are used to form the peak
value curve. This way, the user has an overview of the signal, and low and high portions of
the signal are easily detected.
For a more detailed view of some portions of the signal, the post-processing presents a
time signal curve with a maximum length of 60 seconds (defined by the Length of Signal(s)
control). The starting point of this time signal is specified with the green cursor of the peak
value curve.
The peak graph also has a blue and red cursor. The red cursor indicates the saturation
limit and the blue cursor is used for playback (see section 5.1) and extraction fonctions
(see section 5.4).
Both graphs can be saved in a text file format using the following button:
Signal statistic data
The main interface also presents the standard statistics of the entire signal (or framework):
Channel selection control
Channel selection is done via the Ch# Selection control:
User Manual p. 27