Commercial software

FDIDENT order for industrial use

Frequency Domain System Identification Toolbox

The Frequency Domain System Identification Toolbox (FDIDENT) provides tools to measure, identify and evaluate linear models of dynamic systems, and to evaluate and characterize nonlinearities of a dynamic system. The procedures can be executed either by working with an easy-to-use graphical user interface (GUI), or in the command-line. Objects allow smooth data and model exchange with MATLAB’s control design toolboxes and its System Identification Toolbox.

The toolbox is a collection of frequency domain based procedures. Arbitrary signal forms (even random noise and nonperiodic data) can be properly processed with elimination of leakage or transient effects. Identification starts from either time domain measurements (time series) or frequency domain data (FRF measurements). Model validation incorporates different tests in the frequency domain.

Its current version has been tested under the latest MATLAB versions. Backward compatibility is also maintained. It runs on all types of computers and operational systems where MATLAB also runs.

Frequency Domain System Identification Toolbox

Tools for frequency domain model identification and validation


  • Design of optimized periodic excitation signals (multisine, binary, three-level)
  • Identification of continuous-time or discrete-time systems with unknown fractional delay
  • Model order selection
  • Model validation, including simulation, calculation of residuals, and test of cost functions
  • Calculation of confidence intervals of amplitude/phase and poles/zeros
  • Model conversion to and from the Control System Toolbox and System Identification Toolbox objects



The Frequency Domain System Identification Toolbox (FDIDENT) provides specialized tools for identifying linear dynamic single-input/single-output (SISO) systems from time responses or measurements of the system's frequency response. Frequency domain methods support continuous-time modeling, which can be a powerful and highly accurate complement to the more commonly used discrete-time methods. The methods in the toolbox can be applied to problems such as the modeling of electronic, mechanical, and acoustical systems.

The Frequency Domain System Identification Toolbox is built entirely in MATLAB and all functions are available from the MATLAB command line or through an interactive interface.

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