Owner's manual

Display Units

This control sets the units for the graph and for the global levels.

• dB: decibels.

• dBA or dB(A): decibels after A frequency weighting is

applied.

• rms : root mean square in Unit rms.

• Peak: maximum level.

• rms

Display Graph Type

This control applies to both plots of the graph. The type can be time

signal, global historic or one of the FFT spectrum

• Time Signal: frames of 1/3 s of time signal.

• Historic: History of global levels vs time.

• Instant Spectrum: FFT Spectrum on time signal frames.

• Fast exponential Spectrum: average filter with τ = 1/8 s.

• Slow exponential Spectrum: average filter with τ = 1 s.

• Average Spectrum: linear average.

Reset Average

This button resets the averaging of signal (exponential spectrums

and average spectrum) and also resets the historic graph.

Frequency lin/log

This control sets the X axis of the spectrum graph in linear or

logarithmic scale.

Y rescale

This button adjusts the Y scale to the graph data. If two Y scales are

present on the same graph, both axes are rescaled independently.

and

Magnifier buttons

See section 8.4.1 below for details.

7.4.1 Magnifier

Each graph has a icon at the top left corner. Clicking on this icon pops-up the graph on a

magnified display.

In the particular case where the Frequency Bandwidth is 24 kHz and 4 inputs are enabled, the bottom graph

of the Acquisition Interface will not allow spectrum graph types or dBA units.