Statistical degrees of freedom (DOF) in random vibration analysis quantifies the confidence in a Power Spectral Density (PSD) estimate by relating it to the number of independent data frames used in the Fast Fourier Transform (FFT). [Read More...]

Kurtosis is a statistical measure that describes the "tailedness" or "peakedness" of a probability distribution. In simpler terms, it tells you how much the tails of a distribution differ from the tails of a normal (Gaussian) distribution. [Read More...]

Sigma clipping is a technique used in vibration testing to control the peak amplitudes of a random signal, preventing them from exceeding a user-defined limit. [Read More...]

Spectra Dynamics utilizes an additional clipping method called Ultra Clip in the Sigma clipping option. [Read More...]

Coherence in vibration control is a statistical measure (ranging from 0 to 1) that describes how well two signals are related at a given frequency. [Read More...]

Dynamic range represents one of the most fundamental performance metrics for vibration testing systems, defining the ratio between the largest and smallest signals that can be accurately measured and controlled. [Read More...]

For vibration control systems performing complex signal analysis, real-time control calculations, and high-precision spectral computations, the distinction between true 64-bit native applications and 32-bit applications running on 64-bit operating systems becomes critically important. [Read More...]

The selection of accelerometer sensitivity represents one of the most critical yet frequently overlooked decisions in configuring vibration control systems. [Read More...]

This technical note explores why mixed-mode testing capabilities are essential for accurately simulating real-world environments and why they reveal failure modes that single-mode tests cannot detect. [Read More...]

As test requirements have evolved to simulate increasingly realistic operational environments, the control of phase relationships and coherence between multiple excitation points has emerged as a critical capability that fundamentally affects test validity and product response. [Read More...]

This technical note examines the technical limitations of swept sine testing and explains when stepped sine testing or resonance search and dwell methodologies become necessary to ensure thorough and accurate product qualification.. [Read More...]