getFilterOrders

Get orders of digital down converter or digital up converter filter cascade

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 down converter or digital up converter, 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.

Examples

Get Filter Orders of Digital Up Converter

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
                 SampleRate: 300000

  Use get to show all properties

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.

Get Filter Orders of Digital Up Converter

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
                 SampleRate: 300000

  Use get to show all properties

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

Conv — Digital down converter or digital up converter

dsp.DigitalDownConverter | dsp.DigitalUpConverter

Digital down converter or digital up converter, specified as a dsp.DigitalDownConverter or dsp.DigitalUpConverter System object™.

Output Arguments

S — Filter order information

structure

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 down converter 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 up converter 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