# The Vibration Institute Terminology Project

The focus of the Terminology Project is for our community of trainees and professionals alike to review the current definitions for alterations and edits. If you feel there is room for improvement, please share your constructive thoughts with us. All of the feedback will be reviewed, and definitions will be updated periodically to a new and revised form. Your help in refining these definitions is appreciated.

##### Accelerance

##### Accelerometer

##### Acoustic Emission

##### Algorithm

##### Aliasing

##### Alignment

##### Amplification Factor (Q)

##### Amplitude

##### Analog

##### Analog to Digital Conversion

##### Angularity

##### Anti-Aliasing Filter

##### Apodize, Apodization

##### Asymmetrical Support

##### Asynchronous / Nonsynchronous

##### Attitude Angle

##### Auto Correlation

##### Averaging

##### Axial

##### Axial Float (or End Float)

##### Backlash

##### Band Pass Filter

##### Bandwidth

##### Baseplate

##### Bearing

##### Bearing Frequencies

##### Bearing Misalignment

##### Bearing Nomenclature

##### Beat Frequency

##### Bins

##### Binwidth

##### Bit

##### Bode Plot

##### Bolt Bound

##### Bow

##### Buffer

##### Bump Testing

##### Calculated peak

##### Cepstrum

##### Characteristic Equation

##### Circle Fit

##### Coefficient of Thermal Expansion

##### Coherence

##### Coherence Function

##### Co-Incident

##### Cold Alignment

##### Complex Modes

##### Compliance

##### Coulomb Damping

##### Coupling

##### Critical Damping

##### Cross Correlation

##### Damped Natural Frequency

##### Damping

##### Damping Factor or Damping Ratio ( )

##### Degrees of Freedom

##### Detector

##### Deterministic

##### Dial Indicator

##### Differentiation

##### Digital

##### Discrete

##### Discrete Fourier Transform

##### Dodd Bars

##### Domain

##### Doweling

##### Driving Point Measurement

##### Dynamic Compliance

##### Dynamic Range

##### Dynamic Stiffness

##### Eccentricity, Mechanical

##### Eccentricity Ratio

##### Eddy current probe

##### Effective Mass

##### Eigenvalue

##### Eigenvalue Problem

##### Eigenvector

##### End Float

##### Engineering Units, EU

##### EU

##### Essinger Bars

##### Exponential (Response) Window

##### Face-Rim Method (or Rim-face method)

##### Fast Fourier Transform (FFT)

##### FFT

##### FFT Analyzer

##### Filter

##### Finite Element Analysis or Modeling

##### Fixed Machine

##### Flattop Window

##### Force Window

##### Forced Response Analysis (Forced Response Simulation)

##### Forced Vibration

##### Foundation

##### Fourier, Jean Baptiste

##### Fourier Transform

##### Fourier Analysis

##### Frequency

##### Frequency

##### Frequency Domain

##### Frequency Response

##### Frequency Response Function (FRF)

##### Frequency Response Matrix

##### Fundamental Frequency

##### Fundamental Train Frequency (FTF)

##### Generalized Coordinates

##### Hamming Window

##### Hanning Window

##### Harmonic

##### Harmonics

##### Hertz

##### High-Pass Filter

##### Hysteresis

##### Hysteresis Damping (Hysteretic Damping, Structural Damping)

##### Imaginary Part

##### Impact Testing

##### Impedance, mechanical

##### Impulse Response

##### Inclinometer

##### Induced Soft Foot

##### Inertance

##### Integration

##### Jackscrew (or Jackbolt)

##### Jack Shaft

##### Lateral Location

##### Leakage

##### Level

##### Line Spacing

##### Line Spectrum

##### Low Pass Filter

A filter that passes signals with less than 3 dB attenuation up to its cutoff frequency, and attenuates the signal above that frequency. The attenuation slope is called the roll off, q.v. An anti-aliasing filter is an example of a low pass filter.