Estimate Frequency Response

NI System Identification

Estimate Frequency Response

Estimates the frequency response of an unknown system using the spectral analysis method.

ParameterDescription
Bode MagnitudeDisplays the Bode magnitude of the estimated frequency response of the unknown system.
Bode PhaseDisplays the Bode phase of the estimated frequency response of the unknown system.
Input SignalsContains the following options:
  • Stimulus signal—Specifies the stimulus input to apply to the model.
  • Response signal—Specifies the output response from the model.
Estimation ParametersContains the following option:
  • Setup—Contains the following options:
    • Window length—Specifies the length of window used in spectral computation. The value of Window length controls the trade-off between bias and variance of the frequency response estimation. The larger the Window length, the larger the variance and the smaller the bias.
    • Number of bins—Specifies the number of frequency points at which the step computes the frequency responses. The default is 256.
    • Frequency in log—Uses the logarithmic interval for the computed frequency points when you place a checkmark in the checkbox. Otherwise, the step equally spaces the computed frequency points.
    • Magnitude in dB—Uses decibels for the magnitude response when you place a checkmark in the checkbox. Otherwise, the magnitude response is a linear unit.