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sdo.requirements.PZNaturalFrequency class

Package: sdo.requirements

Natural frequency bound


Specify bounds on the natural frequency of the poles of a linear system. You can then optimize the model response to meet these bounds using sdo.optimize.

You must have Simulink® Control Design™ software to specify natural frequency requirements.


pznatfreq_req = sdo.requirements.PZNaturalFrequency creates a sdo.requirements.PZNaturalFrequency object and assigns default values to its properties.

pznatfreq_req = sdo.requirements.pznatfreq_req(Name,Value) uses additional options specified by one or more Name,Value pair arguments. Name is a property name and Value is the corresponding value. Name must appear inside single quotes (''). You can specify several name-value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Input Arguments

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Use Name,Value arguments to specify properties of the requirement object during object creation. For example, requirement = sdo.requirements.PZNaturalFrequency('Type','>=') creates an sdo.requirements.PZNaturalFrequency object and specifies the Type property as a lower bound.



Requirement description, specified as a character vector. For example, 'Requirement on signal 1'.

Default: ''


Frequency units of the requirement, specified as one of the following values:

  • 'Hz'

  • 'rad/s'

  • 'rpm'

  • 'kHz'

  • 'MHz'

  • 'GHz'

  • 'rad/nanosecond'

  • 'rad/microsecond'

  • 'rad/millisecond'

  • 'rad/minute'

  • 'rad/hour'

  • 'rad/day'

  • 'rad/week'

  • 'rad/month'

  • 'rad/year'

  • 'cycles/nanosecond'

  • 'cycles/microsecond'

  • 'cycles/millisecond'

  • 'cycles/hour'

  • 'cycles/day'

  • 'cycles/week'

  • 'cycles/month'

  • 'cycles/year'

Default: 'rad/s'


Requirement name, specified as a character vector.

Default: ''


Natural frequency bound. Must be in radians/second and a positive finite scalar.

Default: 2


Natural frequency bound type, specified as one of the following values:

  • '<=' — Upper bound

  • '>=' — Lower bound

  • '==' — Equality bound

  • 'max' — Maximization objective

Default: '>='


copyCopy design requirement
getGet design requirement property values
setSet design requirement property values
evalRequirementEvaluate design requirement

Copy Semantics

Handle. To learn how handle classes affect copy operations, see Copying Objects.


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Construct a natural frequency object and specify the natural frequency.

r = sdo.requirements.PZNaturalFrequency;
r.NaturalFrequency = 1;

Alternatively, you can specify the natural frequency during construction.

r = sdo.requirements.PZNaturalFrequency(...


Use getbounds to get the bounds specified in a Check Pole-Zero Characteristics (Simulink Control Design) block.