Octave Analyzer (Add-On) - National Instruments 4551 User Manual

Octave Analyzer (Add-On)

© National Instruments Corporation
In Octave analyzer mode, your NI 45XX can perform fractional-octave
analysis and level measurements in real time. The basic analyzer
architecture, features, and operation are discussed in this section.
The NI-DSA Real-Time Octave Analysis (RTOA) software add-on for
NI-DSA supports:
• Fractional-octave analysis for 1/1, 1/3 and 1/12 octave analysis, with
the following averaging modes:
– Linear
– Exponential—slow, fast, custom
– Impulse
– Peak Hold
– Equal Confidence
• Level measurements, with the following averaging modes
– Linear (Leq)
– Exponential—slow, fast, custom
– Impulse
– Impulse-Eq
– Peak Hold
• A-, B-, and C-weighting
With the RTOA, you can do octave, level, or both octave and level
measurements, and have the additional option of specifying the weighting
if required.
All octave and level measurements are returned as RMS
(root-mean-square) values. The RMS value of a signal is a measure of the
energy it contains. In terms of vibration signals, it can be viewed as the
destructive ability of the signal. Level measurements return the total
amount of energy contained in the signal, and octave measurements return
the amount of energy contained in different frequency bands.
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Chapter 6 Advanced Concepts
NI-DSA Software User Manual