Bode Analysis

NI System Identification

Bode Analysis

Computes a Bode plot for a system model. This step computes the frequency response function (FRF) for one input-output pair of a system model. The step then produces the FRF on XY graphs as Bode magnitude and Bode phase plots.

ParameterDescription
Bode magnitude plotDisplays the Bode magnitude plot of the FRF and the confidence level.
Bode phase plotDisplays the Bode phase plot of the FRF and the confidence level.
Input ModelContains the following option:
  • Model—Specifies the estimated model to use for Bode analysis.
ConfigurationContains the following options:
  • Input source—Specifies the input source type to compute the transfer function. You can select stimulus or noise.
  • Graph Settings—Contains the following option:
    • Confidence level—Specifies the confidence interval of the FRF. The confidence radius equals confidence level times the standard deviations of the FRF. The default is 99%.
    • Magnitude unit—Specifies the type of scaling used for the magnitude axis. You can choose from the following scaling types:
      • dB (default)
      • linear
  • Frequency Information—Contains the following options:
    • Start frequency—Specifies the starting frequency of the data plot. The default is 10m.
    • End frequency—Specifies the end frequency of the data plot. The default is 500m.
    • Number of bins—Specifies the number of frequency points at which frequency responses are computed. The default is 1000.
    • Interval type—Specifies the type of scaling used for the frequency axis, or x-axis. You can choose from the following scaling types:
      • logarithmic (default)
      • linear