Multiple-Input Multiple-Output (MIMO) FRF Testing

EDM Modal MIMO FRF Testing includes a dedicated test setup and operation process flow using multiple simultaneous shakers to acquire FRF signals. Using a large channel count data acquisition system (i.e., Spider- 80X or Spider-80Xi), this shaker excitation method provides much higher efficiency and accuracy for the FRF measurements while minimizing local stresses on the test article.

When using multiple shaker random excitation applications, the shaker-driving Source signals are guaranteed to be uncorrelated with one another. The Source Output type supports pure random (white noise), burst random, chirp/burst chirp, pseudo random, and periodic random. For periodic random types (pseudo random and periodic random), the delay block and cyclic block numbers can be set so that the structure exhibits steady-state response, allowing precise window-free analysis.

Multiple shaker excitation is useful to separate and clearly identify repeated roots and frequency-proximate modes. With more than one reference shaker, multiple columns of the Frequency Response Matrix can be measured simultaneously. Combined with the poly reference curve fitting algorithm, the modal participation factor will help to isolate the repeated and highly coupled modes.

MIMO FRF Periodic Random.png

The modal analysis process is seamlessly integrated with the MIMO FRF testing.


  • Ease of use testing process

  • Point/direction auto/manual increment

  • Synchronized outputs

  • One or multiple excitation (reference)

  • Source trigger mode for synchronized acquisition and source excitation

  • Random, burst random, pseudo random, period random, chirp/burst chirp output types

  • Delay block and cyclic block number setting for pseudo/periodic random

  • Scope tab to view channel data before measurement

  • H1, H2, H3, and Hv estimation