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Create an options object for second-order section scaling


opts = scaleopts(biquad)
opts = scaleopts(biquad,Name,Value)


opts = scaleopts(biquad) uses the current settings in the dsp.BiquadFilter System object™, biquad, to create an options object opts that contains specified scaling options for second-order section scaling. You can pass opts as an input to scale to apply scaling settings to a second-order filter.

opts = scaleopts(biquad,Name,Value) creates an options object with additional options specified by one or more Name,Value pair arguments.

Input Arguments

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dsp.BiquadFilter filter System object.

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside single quotes (' '). You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

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Specify the arithmetic used during analysis. When you specify 'double' or 'single', the function performs double- or single-precision analysis. When you specify 'fixed' , the arithmetic changes depending on the setting of the CoefficientDataType property and whether the System object is locked or unlocked.

 Details for Fixed-Point Arithmetic

When you do not specify the arithmetic, the function uses double-precision arithmetic if the filter System object is in an unlocked state. If the System object is locked, the function performs analysis based on the locked input data type.

Output Arguments


Scaling object. The following table lists the properties of opts.



Description and Valid Value



Reorder section prior to scaling.

Valid options are 'auto' (default), 'none', 'up', 'down', 'lowpass', 'highpass', 'bandpass', and 'bandstop'.



Maximum allowed value for numerator coefficients.



Specifies whether and how to constrain numerator coefficient values. Options are 'none' (default), 'unit', 'normalize', and 'po2'.



Sets the way the filter handles arithmetic overflow situations during scaling. Valid options are 'wrap' (default), 'saturate', and 'satall'.



Specify whether to constrain the filter scale values, and how to constrain them. Valid options are 'unit' (default), 'none', and 'po2'.


'Not used'

Maximum allowed scale values. The filter applies the MaxScaleValue limit only when you set ScaleValueConstraint to a value other than unit. Setting MaxScaleValue to a numerical value automatically changes the ScaleValueConstraint setting to none.


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Create an options scaling object that contains the scaling options settings you require.

EllipI = design(fdesign.lowpass('N,Fp,Ap,Ast',10,0.5,0.5,20), 'ellip', 'FilterStructure', 'df1sos','SystemObject',true)
EllipI = 
  dsp.BiquadFilter with properties:

                       Structure: 'Direct form I'
                 SOSMatrixSource: 'Property'
                       SOSMatrix: [5x6 double]
                     ScaleValues: [6x1 double]
      NumeratorInitialConditions: 0
    DenominatorInitialConditions: 0
        OptimizeUnityScaleValues: true

  Show all properties

opts = scaleopts(EllipI)
opts =

              sosReorder: 'auto'
            MaxNumerator: 2
     NumeratorConstraint: 'none'
            OverflowMode: 'wrap'
    ScaleValueConstraint: 'unit'
           MaxScaleValue: 'Not used'

See Also


Introduced in R2011a

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