The toolbox for spectrum analysis, statistics and more

VibraTools™ contains functions for basic noise and vibration analysis. It includes, for example, data import/export, data storage and retrieval, filtering, spectrum analysis, data quality analysis, and order tracking.

Data Import

Although there is currently no data acquisition implemented in VibraTools, there are many ways of acquiring data into
MATLAB. In VibraTools there are import commands for many popular file formats, such as Universal file, HP’s SDF format, SONY and TEAC file formats etc. If you want to acquire data directly into MATLAB, the Data Acquisition Toolbox (available from The MathWorks Inc.) offers support for a variety of hardware.

Data Quality Assessment

Before analyzing data, particularly from field measurements, it is often desirable to perform some data quality assessment to ensure that data showing signs of quality issues be looked at closer, and erroneous data eliminated from further analysis. Such data quality assessment is done by computing various statistical measures, such as rms value, skewness, kurtosis etc., and comparing the computed values with “normal” values. In addition, the amplitude probability density and tests for stationarity are often applied to check the data. Analysis procedures for data quality assessment are supported by very high-level commands in VibraTools helping to assess the quality of large channel counts easily and quickly.

Vibration Analysis

VibraTools contains physically scaled spectrum analysis (FFT) functions for any type of signal, be it periodic, random, or transient. In addition, the toolbox contains a comprehensive set of functions for different analysis procedures commonly applied to vibration signals, including time domain weighting filters for whole-body and hand-arm vibrations specified by the ISO 2631 and ISO 8041 standards. There are also state-of-the-art integration and differentiation functions in the time domain, to convert between acceleration, velocity and displacement, as well as frequency domain integration and differentiation. The integration in time domain can be done accurately even on difficult signals with low frequency content by an implemented highpass filter.

Acoustics

For acoustic applications, VibraTools include time domain and frequency domain A- and C-weighting filters, and fast digital filters for octave- and third-octave analysis, that allow you to compute results exactly identical to the results from a parallel analyzer. Of course you can also produce a third octave spectrum from a narrow-band (FFT based) spectrum. All filters meet applicable ISO, IEC, and ANSI standards.

RPM Analysis (Order Tracking)

Analyzing rotating machines is an important part of vibration analysis and acoustics. In VibraTools you find state-of-the art functions for producing RPM maps (waterfall plots), including color intensity plots, and you can extract order tracks using fixed sampling frequency or resampling the data to a synchronous sampling frequency. With the Vold-Kalman filters implemented in the toolboxes you can extract the time signals corresponding to any order, for use in for example sound quality analysis. The Vold-Kalman filters are also superior to traditional techniques if you have several independent rotational speeds in your machine, and the orders cross at certain RPMs.

Menus

In some cases, you may want to make a simple user interface for a particular analysis task. MATLAB contains advanced functionality for creating your own user interfaces. However, this is also supported by some simplified functions in the toolboxes. The implemented menu systems are easier to set up quickly, and give you a particular VibraTools “look and feel”. As an example, we provide a one-channel FFT analyzer among the powerful examples are included in The VibraTools Suite.

Key Features

• Standard data storage format with header values for noise and vibration signals, such as measurement position, direction, etc.
• Import/export of data in for example universal file format, SONY DAT recorder binary format, standard ASCII formats
• Easy computation of FFT based scaled spectra for all common signal types such as periodic, random and shocks
• Time windows: Hanning, flattop
• Auto-, and cross correlation functions
• Octave- and third-octave filters based on
digital filtering
• Time weighting filters: Acoustic A-, and C-weighting, ISO-filters
• Statistical functions: amplitude probability density,skewness, kurtosis, normality test, stationarity test
• Common plot functions: Bode plots with variable formats, bar graphs, waterfall plots
• Functions for simplified graphical user interface (GUI) definition

Requirements

MATLAB 5.1 or higher from The MathWorks Inc.
Signal Processing Toolbox from The MathWorks Inc.

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