Frequency Response VIs
Owning Palette: Control Design VIs and Functions
Installed With: Control Design and Simulation Module. This topic might not match its corresponding palette in LabVIEW depending on your operating system, licensed product(s), and target.
Use the Frequency Response VIs to analyze a system model in the frequency domain.
The VIs on this palette can return general LabVIEW error codes or specific control design error codes.
| Palette Object | Description |
|---|---|
| CD All Margins | Calculates all the gain and phase margins, which result from the frequency response crossing at 0 decibels (magnitude) and –180 degrees (phase). You can use the CD All Margins VI only with single-input single-output (SISO) systems. You can use this polymorphic to calculate the gain and phase margins of state-space models, transfer function models, zero-pole-gain models, and stand-alone frequency response data. The data types you wire to the State-Space Model and Frequency Info inputs determine the polymorphic instance to use. |
| CD Bandwidth | Calculates the frequency, relative to the DC gain, at which the magnitude of the frequency response drops below Magnitude Drop (dB). You can use the CD Bandwidth VI only with single-input single-output (SISO) systems. The data type you wire to the State-Space Model input determines the polymorphic instance to use. |
| CD Bode | Produces the Bode magnitude and Bode phase plots of the system model on an XY graph. The data types you wire to the State-Space Model and Frequency Info inputs determine the polymorphic instance to use. |
| CD Evaluate at Frequency | Determines the magnitude and phase of the system at the given frequency. The data type you wire to the State-Space Model input determines the polymorphic instance to use. |
| CD Gain and Phase Margin | Calculates the gain and phase margins. If a system has multiple crossover frequencies, the CD Gain and Phase Margin VI returns the smallest gain and phase margins. You can use the CD Gain and Phase Margin VI only with single-input single-output (SISO) systems. The data types you wire to the State-Space Model and Frequency Info inputs determine the polymorphic instance to use. |
| CD Get Frequency Response Data | Gives access to the frequency response information the Frequency Response VIs return. The data types you wire to the Input and Output inputs determine the polymorphic instance to use. To get the frequency response data from all input-output pairs, you must manually select the polymorphic instance to use. |
| CD Nichols | Creates a Nichols plot of the input system for which this VI plots the magnitude, in decibels, of the frequency response against the phase. You can display this data in the CD Nichols Plot indicator. The data types you wire to the State-Space Model and Frequency Info inputs determine the polymorphic instance to use. |
| CD Nyquist | Produces the Nyquist plot of the input system for which this VI plots the imaginary part of the frequency response against its real part. You can display this data in the CD Nyquist Plot indicator. The data types you wire to the State-Space Model and Frequency Info inputs determine the polymorphic instance to use. |
| CD Singular Values | Calculates the singular values of the frequency response of the input model. The data types you wire to the State-Space Model and Frequency Info inputs determine the polymorphic instance to use. |