The Auto Spectral Density or Auto RMS spectrum analyses uses Fourier Transforms to process optionally overlapped sections of the input data. The result of each Fourier analysed section is called a periodogram. We then process all the resulting periodograms to produce a spectral result. Continue reading What is Auto Spectral Density?
What sample rate should I use if I am measuring whole body vibration?
Strict ISO8041 compliance imposes a minimum sample rate of 900 samples per second. This ensures the amplitude and phase characteristics of the applied weightings meet the required criteria. To take account of the anti alias hardware filter we would recommend 1200 samples/second. If non-strict compliance is used the minimum sample rate is 300 samples/second.
ISO2631-1 recommends a minimum data duration of 227 seconds. However, for greater reliability, 600 seconds is now considered essential. That is, a 600 second or longer signal will be more representative and will provide better quality results.
The DATS Modal Analysis software consists of Hammer Impact Testing, Modal Analysis & Structural Animation (often referred to as Operational Deflection Shapes or ODS and Running Modes). Having measured and analysed your data the Structural Animation software allows you to visualisation your structure under certain operating conditions. These visualisations can then be saved as AVI files. This video shows you how…
In the process of looking at some order data, a question about the accuracy of the measurement of the signal level of discrete frequency signals which were close to the general noise level. To answer this question, a small DATS worksheet was created which generated 2 signals. The first signal was a 35 Hz sinusoid which, by itself the spectrum level was measured to be approximately -9 dB (ref 1 V) as seen in Figure 1.