modulator

Modulator object

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Description

Use the modulator object to create a modulator element. A modulator is a 2-port RF circuit object. You can use this element in the rfbudget object and the circuit object.

Creation

Syntax

mod = modulator
mod = modulator(Name=Value)

Description

mod = modulator creates a modulator object, mod, with default property values.

example

mod = modulator(Name=Value) creates a modulator object with additional properties specified by one or more name-value pair arguments. Properties not specified retain their default values.

example

Properties

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Name of modulator, specified as the comma-separated pair consisting of 'Name' and a character vector. All names must be valid MATLAB® variable names.

Example: Name='mod'

Since R2024b

Conversion type, specified as either:

  • 'mod' — Modulator

  • 'demod' — Demodulator

Example: Model='demod'

Since R2026a

Sideband of a modulator, specified as either:

  • 'upper' — This is the default value when Model is set to 'demod' and denotes that the RF carrier frequency is higher than local oscillator frequency.

  • 'lower' — This is the default value when Model is set to 'mod' and denotes that the RF carrier frequency is lower than local oscillator frequency.

This table summarizes the modulator operations when Sideband is set.

Input/OutputModelSidebandOperation
RF/IF'demod''lower'IF = LO - RF
'upper'IF = RF - LO
IF/RF'mod''lower'RF = LO - IF
'upper'RF = LO + IF

Example: Sideband='upper'

Available power gain, specified as a nonnegative scalar in dB.

Example: Gain=10

Noise figure, specified as a real finite nonnegative scalar in dB.

Example: NF=10

Since R2026a

Second-order input-referred intercept point, specified as a real positive number in dBm.

Example: IIP2=8

Since R2026a

Third-order input-referred intercept point, specified as a real positive number in dBm.

Example: IIP3=10

Since R2026a

Input 1 dB compression point, specified as a real positive number in dBm.

Example: IP1dB=20

Since R2026a

Input saturation point, specified as a positive real number in dBm.

Example: IPsat=20

Local oscillator frequency, specified as a real finite positive scalar in Hz.

Example: LO=2e9

Name of the two-port Touchstone file that contains modulator data, specified as a string scalar or character vector.

Example: FileName='default.s2p'

Since R2026a

Modulator system data, specified as an rfSystemParameters object.

Example: SystemData=rfSystemParameters('Mod_model.csv')

Ideal image reject filtering at the input of the modulator, specified as a numeric or logical 1 (true) or 0 (false). Setting this property to false or 0 might affect harmonic balance results.

Example: ImageReject=1

Example: ImageReject=true

Ideal channel select filtering at the output of the modulator, specified as a numeric or logical 1 (true) or 0 (false). Setting this property to false or 0 might affect harmonic balance results.

Example: ChannelSelect=1

Example: ChannelSelect=false

Input impedance, specified as a positive real part finite scalar in ohms. You can also use a complex value with a positive real part.

Example: Zin=40

Output impedance, specified as a scalar in ohms. You can also use a complex value with a positive real part.

Example: Zout=40

Number of ports, specified as a scalar integer. This property is read-only.

Names of port terminals, specified as a cell vector. This property is read-only.

Object Functions

cloneCreate copy of existing circuit element or circuit object

Examples

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Open Live Script

Create a downconverter modulator with a local oscillator (LO) frequency of 100 MHz.

m = modulator(Model='demod',LO=100e6)
m = 
  modulator: Modulator element

             Name: 'Modulator'
            Model: 'demod'
               LO: 100000000
             Gain: 0
              Zin: 50
             Zout: 50
               NF: 0
             IIP2: Inf
             IIP3: Inf
            IP1dB: Inf
            IPsat: Inf
            OPsat: Inf
      ImageReject: 1
    ChannelSelect: 1
Open Live Script

Create a modulator object with a gain of 4 dB and local oscillator (LO) frequency of 2 GHz. Create another modulator object has an output third-order intercept (OIP3) of 13 dBm.

mod1 = modulator(Gain=4,LO=2e9);
mod2 = modulator(OIP3=13);

Build a two-port circuit using the modulators.

c = circuit([mod1 mod2])
c = 
  circuit: Circuit element

    ElementNames: {'Modulator'  'Modulator_1'}
        Elements: [1×2 modulator]
           Nodes: [0 1 2 3]
            Name: 'unnamed'
Open Live Script

Create an amplifier with a gain of 4 dB.

a = amplifier(Gain=4);

Create a modulator with an OIP3 of 13 dBm.

m = modulator(OIP3=13);

Create an N-port element using passive.s2p.

n = nport('passive.s2p');

Create an RF element with a gain of 10 dB.

r = rfelement(Gain=10);

Calculate the RF budget of a series of RF elements at an input frequency of 2.1 GHz, an available input power of –30 dBm, and a bandwidth of 10 MHz.

b = rfbudget([a m r n],2.1e9,-30,10e6)
b = 
  rfbudget with properties:

               Elements: [1x4 rf.internal.rfbudget.Element]
         InputFrequency: 2.1 GHz
    AvailableInputPower: -30 dBm
        SignalBandwidth:  10 MHz
                 Solver: Friis      
             AutoUpdate: true

   Analysis Results
        OutputFrequency: (GHz) [  2.1    3.1    3.1     3.1]
            OutputPower: (dBm) [  -26    -26    -16   -20.6]
         TransducerGain: (dB)  [    4      4     14     9.4]
                     NF: (dB)  [    0      0      0  0.1391]
                   IIP3: (dBm) [  Inf      9      9       9]
                   OIP3: (dBm) [  Inf     13     23    18.4]
                    SNR: (dB)  [73.98  73.98  73.98   73.84]

Type the show command at the command window to display the analysis in the RF Budget Analyzer app.

show(b)

amp_rf_app.png

Version History

Introduced in R2017a

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See Also

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