Documentation

Create Plots

Available Data for Plotting

SimRF™ Equivalent Baseband software lets you validate the behavior of individual RF components and physical subsystems in your model by plotting the following data:

  • Large- and small-signal S-parameters

  • Noise figure, noise factor and noise temperature

  • Output third-order intercept point

  • Power data

  • Phase noise

  • Voltage standing-wave ratio

  • Transfer function

  • Group delay

  • Reflection coefficients

    Note:   When you plot information about a physical block, the blockset plots the actual frequency response of the block, as specified in the block dialog box. The blockset does not plot the frequency response of the complex-baseband model that it uses to simulate the block, in which the frequency response is centered at zero. For more information on how the blockset simulates physical blocks, see SimRF Equivalent Baseband Algorithms.

Validate Individual Blocks and Subsystems

You can plot model data for an individual physical block or for a physical subsystem. A subsystem is a collection of one or more physical blocks bracketed by an Input Port block and an Output Port block. To understand the behavior of specific subsystems, plot the data of the corresponding Output Port block after you run a simulation.

To validate the behavior of individual RF components in the model, plot the data of the corresponding physical blocks. You can plot data for individual blocks from each of these components either before or after you run a simulation.

You create a plot by selecting options in the block dialog box, as shown in Create and Modify Subsystem Plots. To learn about the available plots, see Types of Plots. For more information about creating plots, see How to Create a Plot.

Types of Plots

SimRF Equivalent Baseband software provides a variety of plots for analyzing the behavior of RF components and subsystems. The following table summarizes the available plots and charts and describes each one.

Plot TypePlot Contents
X-Y Plane (Rectangular) Plot

Parameters as a function of frequency, input power, or operating condition, such as

  • S-parameters

  • Noise figure (NF), Noise factor (NFactor), and Noise Temperature (NTemp)

  • Voltage standing-wave ratio (VSWR)

  • Output third-order intercept point (OIP3)

  • Input and output reflection coefficients (GammaIn and GammaOut)

Link Budget Plot (3-D)

Parameters as a function of frequency for each component in a physical subsystem

where

The curve for a given component represents the cumulative contribution of each RF component up to and including the parameter value of that component.

For more information, see Link Budget.

Polar Plane Plot

Magnitude and phase of parameters as a function of frequency or operating condition, such as

  • S-parameters

  • Input and output reflection coefficients (GammaIn and GammaOut)

Smith® ChartReal and imaginary parts of S-parameters as a function of frequency or operating condition, used for analyzing the reflections caused by impedance mismatch.
Composite PlotMultiple plots and charts in one figure.

To learn how to create these plots, see How to Create a Plot.

Plot Formats

When you create a plot from a block dialog box, you must specify the format of the data for both the x- and y-axes.

These plot options define how SimRF Equivalent Baseband software displays the data on the plot.

The available formats vary with the data you select to plot. The data you can plot depends on the plot type you select. The plot formats determine whether the blockset converts the data to a new set of units, or performs a calculation on the data. For example, setting the format to Real tells the blockset to compute and plot the real part of the parameter.

The following topics describe the available parameters and formats for each plot type:

Composite Data

The composite data plot automatically generates four separate plots in one figure window, showing the frequency dependence of several parameters. The following figure shows an example of such a plot.

Example — Composite Data Plot

    Note:   For composite data plots, you do not need to specify the parameters or the formats—they are set automatically.

The combination of plots differs based on the type of block and the specified block data. The following table describes the contents of the composite data plot for each specification. The Plot Contents column lists the types of plots as they appear on the composite plot, counterclockwise and starting in the upper-left corner. The blockset plots all data as a function of frequency.

BlockSpecified DataPlot Contents
General Amplifier or General Mixer

Network parameters

OR

Network parameters and noise

  • X-Y plot, magnitude of S12 and S21 in decibels

  • X-Y plot, phase of S12 and S21 in degrees

  • Z Smith Chart, real and imaginary parts of S11 and S22

  • Polar plot, magnitude and phase of S11 and S22

Network parameters and power

OR

Network parameters, noise, and power

  • X-Y plot, magnitude of S12 and S21 in decibels

  • X-Y plot, output power (Pout) in dBm (decibels referenced to one milliwatt)

  • Z Smith Chart, real and imaginary parts of S11 and S22

  • Polar plot, magnitude and phase of S11 and S22

Other Physical block

Network parameters

OR

Network parameters and noise (S-, Y-, and Z-Parameters Amplifiers and Mixers only)

    Note:   Only the General Amplifier and General Mixer blocks accept power data.

  • X-Y plot, magnitude of S12 and S21 in decibels

  • X-Y plot, phase of S12 and S21 in degrees

  • Z Smith Chart, real and imaginary parts of S11 and S22

  • Polar plot, magnitude and phase of S11 and S22

X-Y Plane

You can plot any parameters that are relevant to your block on an X-Y plane plot. For this type of plot, you specify data for both the x- and y-axes. If you specify two Y parameters, and you specify different formats for the two Y parameters, the blockset plots the second Y parameter on the right y-axis.

The following table summarizes the available Y parameters and formats. The parameters and formats are the same for both the left and right y-axes.

    Note:   LS11, LS12, LS21, and LS22 are large-signal S-parameters. You can plot these parameters as a function of input power or as a function of frequency.

Y Parameter

Y Format

S11, S12, S21, S22

LS11, LS12, LS21, LS22 (General Amplifier and General Mixer blocks with multiple operating conditions only)

Magnitude (decibels)
Magnitude (linear)
Angle (degrees)
Angle (radians)
Real
Imaginary

NF

Magnitude (decibels)

NFactor

None
This format tells the blockset to plot the noise factor as it is specified to or calculated by the block.

NTemp

Kelvin

OIP3

dBm
dBW
W
mW

VSWRIn, VSWROut

Magnitude (decibels)
None
This format tells the blockset to plot the voltage standing-wave ratio as it is specified to or calculated by the block.

Pout (General Amplifier and General Mixer blocks with power data only)

dBm
dBW
W
mW

Phase (General Amplifier and General Mixer blocks with power data only)

Angle (degrees)
Angle (radians)

AM/AM (General Amplifier and General Mixer blocks with power data only)

Magnitude (decibels)
None
This format tells the blockset to plot the AM/AM conversion as it is specified to or calculated by the block.

AM/PM (General Amplifier and General Mixer blocks with power data only)

Angle (degrees)
Angle (radians)

PhaseNoise (Mixer blocks only)

dBc/Hz

FMIN (Amplifier and Mixer blocks with spot noise data only)

Magnitude (decibels)
None
This format tells the blockset to plot the minimum noise figure as it is specified to or calculated by the block.

GammaIn, GammaOut(Output Port block only)

Magnitude (decibels)
Magnitude (linear)
Angle (degrees)
Angle (radians)
Real
Imaginary

GAMMAOPT (Amplifier and Mixer blocks with spot noise data only)

Magnitude (decibels)
Magnitude (linear)
Angle (degrees)
Angle (radians)
Real
Imaginary

RN (Amplifier and Mixer blocks with spot noise data only)

None
This format tells the blockset to plot the noise resistance as it is specified to or calculated by the block.

The available X parameters depend on the Y parameters you select. The following table summarizes the available X parameters for each of the Y parameters in the preceding table.

Y ParameterX Parameter
Pout, Phase, LS11, LS12, LS21, LS22Pin
Freq
S11, S12, S21, S22, NF, OIP3, VSWRIn, VSWROut, GAMMAIn, GAMMAOut, FMIN, GAMMAOPT, RNFreq
AM/AM, AM/PMAM

The following table shows the X formats that are available for the X parameters listed in the preceding table.

X ParameterX Format
PindBm
dBW
W
mW
FreqTHz
GHz
MHz
KHz
Hz
Auto (xformat is chosen to provide the best scaling for the given xparameter values.)
AMMagnitude (dB)
Magnitude (linear)

When you import block data from a .p2d or .s2d file, you can also plot Y parameters as a function of any operating condition from the file that has numeric values, such as bias. You can specify an operating condition as the X parameter only when validating individual blocks, and the format is always None. This format tells the blockset to plot the operating condition values as they are specified in the file.

Link Budget

You use the Link budget plot to understand the individual contribution of each block to a plotted Y parameter value in a physical subsystem with multiple components between the Input Port and the Output Port blocks.

The link budget plot is a three-dimensional plot that shows one or more curves of parameter values as a function of frequency, ordered by the subsystem circuit index.

The following figure shows how the circuit index is assigned to a component in a physical subsystem based on its sequential position in the subsystem.

A curve on the link budget plot for each circuit index represents the contributions to the parameter value of the RF components up to that index. The following figure shows an example of a link budget plot.

Example — Link Budget Plot

The following table summarizes the Y parameters and formats that are available for a link budget plot.

Y Parameter

Y Format

S11, S12, S21, S22

Magnitude (decibels)
Magnitude (linear)
Angle (degrees)
Real
Imaginary

OIP3

dBm
dBW
W
mW

NF

Magnitude (decibels)
Magnitude (linear)

NFactor

None
This format tells the blockset to plot the noise factor as it is specified to the block.

NTemp

Kelvin

If you specify two Y parameters, the blockset puts both parameters in a single plot. The Y parameters must have the same formats.

For a link budget plot, the X parameter is always Freq. The format of the X parameter specifies the units of the x-axis.

Polar Plane Plots and Smith Charts

You can use SimRF Equivalent Baseband software to generate Polar plots and Smith Charts. When you select these plot types, you do not need to specify the format of any Y parameters—the formats are set automatically. If you specify two Y parameters, the blockset puts both parameters in a single plot.

The following table describes the Polar plot and Smith Chart options. It also lists the available Y parameters.

Plot Type

Y Parameter

Polar plane

S11, S12, S21, S22

LS11, LS12, LS21, LS22 (General Amplifier and General Mixer blocks with data from a P2D file only)

GammaIn, GammaOut (Output Port block only)

Z Smith chart

S11, S22

LS11, LS22 (General Amplifier and General Mixer blocks with data from a P2D file only)

GammaIn, GammaOut (Output Port block only)

Y Smith chart

S11, S22

LS11, LS22 (General Amplifier and General Mixer blocks with data from a P2D file only)

GammaIn, GammaOut (Output Port block only)

ZY Smith chart

S11, S22

LS11, LS22 (General Amplifier and General Mixer blocks with data from a P2D file only)

GammaIn, GammaOut (Output Port block only)

By default, the X parameter is Freq. The format of the X parameter specifies the units of the x-axis. When you import block data from a .p2d or .s2d file, you can also plot Y parameters as a function of any operating condition from the file that has numeric values, such as bias. You can specify an operating condition as the X parameter only when validating individual blocks, and the format is always None.

How to Create a Plot

  1. Double-click the block to open the block dialog box, and select the Visualization tab. The following figure shows the contents of the tab.

  2. Select the Source of frequency data.

    This value is the source of the frequency values at which to plot block data. The following table summarizes the available types of sources for the various types of blocks.

    Source of frequency dataDescriptionBlocks
    User-specified

    Vector of frequencies that you enter.

    When you select User-specified in the Source of frequency data list, the Frequency range (Hz) field is displayed. Enter a vector specifying the range of frequencies you want to plot.

    For example, to plot block data from 0.3 MHz to 5 GHz by 0.1 MHz, enter [0.3e6:0.1e6:5e9].

      Note:   When you select PhaseNoise in the Parameter list and User-specified in the Source of frequency data list, the Frequency range (Hz) field is disabled. You use the Phase noise frequency offset (Hz) block parameter to specify the frequency values at which to plot block data.

    All physical blocks
    Derived from Input Port parameters (Available after running a simulation or clicking the Update Diagram button )Modeling frequencies derived from the Input Port block parameters. For information on how the blockset computes the modeling frequencies, see Determine Modeling Frequencies.All physical blocks
    Same as the S-parametersFrequency values specified in the Frequency block parameter.S-Parameters Passive Network, S-Parameters Amplifier, S-Parameters Mixer
    Same as the Y-parametersFrequency values specified in the Frequency block parameter.Y-Parameters Passive Network, Y-Parameters Amplifier, Y-Parameters Mixer
    Same as the Z-parametersFrequency values specified in the Frequency block parameter.Z-Parameters Passive Network, Z-Parameters Amplifier, Z-Parameters Mixer
    Extracted from data sourceFrequency values imported into the Data file or RFDATA object block parameter.General Passive Network, General Amplifier, and General Mixer

  3. Enter the Reference impedance.

    This value is the reference impedance to use when plotting small-signal parameters.

  4. Select the Plot type.

    This value is the type of plot. For a description of the options, see Types of Plots.

  5. Select the following parameters:

    • Y Parameter1 — The first parameter for the Y-axis.

    • Y Parameter2 — The second parameter for the Y-axis (optional).

    • X Parameter — The parameter for the X-axis.

    These parameters specify the data to be plotted. The available choices vary with the type of plot. For a description of the options for a particular plot type, see the topic on that plot type in Plot Formats.

  6. If you select a large-signal parameter for one or more y-axis parameters, select the Source of power data.

      Note:   Large-signal parameters are available only for General Amplifier or General Mixer blocks that contain power data.

    This value is the source of the input power values at which to plot block data. The following table summarizes the available types of sources for the General Amplifier and General Mixer blocks.

    Source of frequency dataDescription
    Extracted from data sourceInput power values imported into the Data file or RFDATA object block parameter.
    User-specified

    Vector of power values that you enter.

    When you select User-specified in the Source of power data list, the Input power data (dBm) field is displayed. Enter a vector specifying the range of power values you want to plot.

    For example, to plot block data from 1 dBm to 10 dBm by 2 dBm, enter [1:2:10].

  7. Select the following formats:

    • Y Format1 — The format for the first Y parameter.

    • Y Format2 — The format for the second Y parameter (optional).

    • X Format — The format for the X parameter.

    These are the X and Y formats for plotting the selected parameter. The available choices vary based on the selected parameter. For a description of the options for a particular plot type, see the topic on that plot type in Plot Formats.

  8. Select the X Scale and Y Scale.

    These are the scales on which to plot the data. The available choices are Linear and Log.

  9. Click Plot.

    Note:   By default, the blockset does not add a legend to some plots. To display the plot legend, type legend show at the MATLAB® prompt.

Example — Plot Component Data on a Z Smith Chart

In this example, you simulate the frequency response of an amplifier using data from the default.s2d S2D file.

Using a SimRF Equivalent Baseband example model, you import the data file into a General Amplifier block and validate the amplifier by plotting the S-parameters of the block on a Z Smith Chart.

  1. Type sparam_amp at the MATLAB prompt to open the "AMP Data File for Amplifier" example.

  2. Double-click the General Amplifier block to display its parameters.

    As shown in the preceding figure, the Data source parameter is set to Data fileand the Data file parameter is set to default.s2d. These values tell the blockset to import data from the file default.s2d. The block uses this data, along with the other block parameters, in simulation.

  3. Select the Visualization tab and set the General Amplifier block parameters as follows:

    • In the Plot type list, select Z Smith chart.

    • In the Y Parameter1 list, select S22.

  4. Click Plot.

    This action creates a Z Smith Chart of the S22 parameters using the frequency data from the default.s2d file.

    General Amplifier Frequency Response

    Note:   To display data tips for a plotted line, select Tools > Data Cursor. Click the data cursor on the plotted line to see the frequency and the parameter value at that point. See the MATLAB documentation for more information.

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