5 Time evolution
5.1 Principle and use
The drawing of the evolution of the short equivalent continuous levels is displayed according to a weighting or a filter following a time-
related adjustment suitable for the measurement. It is linked with the screen of the spectral representation by frequency band, before
and during the data storage.
From the screen of spectrum visualization:
➢
Move the cursor in
1
on
Spectrum
icon and with the wheel select
Evolution
icon.
The time evolution is about:
•
the succession of elementary equivalent continuous levels (short Leq) whose duration varies from 1/16°s to 60 s by
programming.
It is limited to the screen width dedicated to the spectrum.
This width is representative of a duration that is also adjustable. Beyond this time, the evolution slides across the screen losing the first
values to display the new ones. This is the FIFO (first in, first out) process.
Example : DI = 1/16s _ Evolution duration on the screen = 10s
There are 2 ways to use this function:
1. with a short duration of the Leq and a few seconds of scrolling time on the screen, you control in real time the immediate
evolution of the noise environment
2. with a short duration of the Leq and an adapted scrolling time on the screen, you can visualize in real time and in the long
term a many hours to several days measurement.
Time evolution
16
1
Spectrum visualization
Evolution visualisation
Drawing of the evolution
after about 6 s.
Start at 10:35:20
Full drawing after 10 s
Sliding drawing after
about 4 s
type FIFO
