Access additional graphing capabilities

Gain a deeper understanding of complex relationships between signals that are not readily apparent in basic graphs. The optional Analyzer module enhances Sine, Random, and Shock tests by comparing the characteristics of two or more signals in a series of graphs. It includes additional graphing capabilities, plots, configurable function generators, and more.


Advanced Graphing Functions

With Analyzer, data can be displayed in a number of advanced graphing functions, including transfer function, total harmonic distortion, coherence, and cross-spectrum. The available graphs are dependent on the test type.

Analyzer also offers a configurable function generator for outputting user-defined voltage waveforms. Pretest uses a low-level drive signal and uses the control and response channels to predict the requirements at full level. Intelligent startup uses the information from the pretest in the full-level control algorithm.

Watch: Analyzer Functions Webinar



Graphs Test Settings
  • Scatter Plot
  • Spectrum
  • Transmissibility vs Phase
  • Pre-Test
  • Analyzer with Swept THD Option
  • Open-Loop Waveform Synthesis Scatter


Graphs Test Settings
  • Cross Spectrum
  • Scatter Plot
  • Transfer Function
  • Coherence
  • Pre-Test with Memorized Drive (Version 2014 and Newer)
  • Open-Loop Waveform Synthesis


Graphs Test Settings
  • Transfer Function
  • Coherence
  • Pre-Test with Memorized Drive; Classical Shock Only
  • Transfer Function Parameters; Transient Capture Only

(Version 2014 and Newer)

Field Data Replication (FDR)

Graphs Test Settings
  • Cross Spectrum
  • Scatter Plot
  • Transfer Function
  • Coherence
  • Open-Loop Waveform Synthesis

Understanding Waveform Relationships

Fast Fourier transform (FFT) and power spectral density (PSD) mathematics are powerful tools for analyzing the characteristics of a waveform. In addition to FFT and PSD, there several types of mathematics used to understand the relationships between two or more waveforms.

To learn more, please enroll in our VRU course Mathematics for Understanding Waveform Relationships.

Transfer Function (Random & Shock)

The transfer function uses two graphs to compare:

  • Ratio of PSD values for two signals across a specified frequency range
  • Phase relationships between the two signals

Use the transfer function graph to determine phase relationships between two signals.

Coherence (Random & Shock)

Identify the relationship between the response signal and drive signal. Two signals are coherent if they have a constant phase difference and the same frequency and waveform.

Total Harmonic Distortion (THD) (Sine)

Determine the amount of harmonic content in a signal by comparing the accelerations at a specific frequency with the accelerations at the next ten harmonics. THD can be used to measure how well a shaker recreates a signal from the controller.

Cross-Spectrum (Random & Shock)

Compares one signal with another signal in time. The Cross-Spectrum graph contains data on the differences in amplitude and phase of the two signals.


The pre-test feature is available only with Analyzer. Pre-test applies a low-level, open-loop output to the shaker and then uses the output and the measured response to predict the amplitude levels of the full-level test.

Watch: Analyzer Functions Pre-Test

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