getFilterOrders

Get orders of digital downconverter or digital upconverter filter cascade

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Syntax

S = getFilterOrders(Conv)

Description

S = getFilterOrders(Conv) returns a structure, S, that contains the number of CIC filter sections and the orders of the FIR filter stages of a digital downconverter or digital upconverter, Conv. The converter usually implements the conversion using three filter stages. Sometimes, one of the stages is bypassed and the order of that filter stage is returned as an empty field.

example

Examples

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Open Live Script

Get orders of each decimation filter stage of the dsp.DigitalUpConverter System object™.

Create a dsp.DigitalUpConverter System object with the default settings.

upConv = dsp.DigitalUpConverter
upConv = 
  dsp.DigitalUpConverter with properties:

        InterpolationFactor: 100
         MinimumOrderDesign: true
                  Bandwidth: 200000
    StopbandFrequencySource: 'Auto'
             PassbandRipple: 0.1000
        StopbandAttenuation: 60
                 Oscillator: 'Sine wave'
            CenterFrequency: 14000000
        NormalizedFrequency: false
                 SampleRate: 300000

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Using the getFilterOrders function, obtain the number of CIC decimator sections, order of the CIC compensation filter stage, and order of the third filter stage.

S = getFilterOrders(upConv)
S = struct with fields:
     FirstFilterOrder: 24
    SecondFilterOrder: 12
       NumCICSections: 4

The first filter order field is empty when the object bypasses the first filter stage.

Input Arguments

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Digital downconverter or digital upconverter, specified as a dsp.DigitalDownConverter or dsp.DigitalUpConverter System object™.

Output Arguments

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Filter order information, returned as a structure containing the number of CIC sections, and the orders of the two FIR filter stages. For a digital downconverter object, the structure contains these fields:

  • NumCICSections –– Number of sections of the CIC decimator. The default is 4.

  • SecondFilterOrder –– Order of the CIC compensation filter stage. The default is 12.

  • ThirdFilterOrder –– Order of the third filter stage. The default is 24. The ThirdFilterOrder structure field is empty if the third filter stage has been bypassed.

For a digital upconverter object, the structure contains these fields:

  • FirstFilterOrder –– Order of the first filter stage. The default is 24. The FirstFilterOrder structure field is empty if the first filter stage has been bypassed.

  • SecondFilterOrder –– Order of the CIC compensation filter stage. The default is 12.

  • NumCICSections –– Number of sections of the CIC interpolator. The default is 4.

Version History

Introduced in R2012a

See Also

Functions

Objects