null  null
RF Blockset
For Use with Simulink®
Modeling
Simulation
Implementation
User’s Guide
Version 1
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RF Blockset User’s Guide
© COPYRIGHT 2004–2006 by The MathWorks, Inc.
The software described in this document is furnished under a license agreement. The software may be used
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Revision History
June 2004
August 2004
March 2005
September 2005
March 2006
September 2006
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New for Version 1.0 (Release 14)
Revised for Version 1.0.1 (Release 14+)
Revised for Version 1.1 (Release 14SP2)
Revised for Version 1.2 (Release 14SP3)
Revised for Version 1.3 (Release 2006a)
Revised for Version 1.3.1 (Release 2006b)
Contents
Getting Started
1
What Is the RF Blockset? . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-2
Required and Related Products . . . . . . . . . . . . . . . . . . . . .
1-3
Product Demos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-4
RF Blockset Libraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Opening RF Blockset Libraries . . . . . . . . . . . . . . . . . . . . . .
Physical Library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mathematical Library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-6
1-6
1-7
1-9
RF Blockset Workflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-10
Example — Modeling an LC Bandpass Filter . . . . . . . . .
Selecting Blocks to Represent System Components . . . . . .
Building the Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifying Model Parameters . . . . . . . . . . . . . . . . . . . . . . . .
Validating Filter Components and Running the
Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Analyzing the Simulation Results . . . . . . . . . . . . . . . . . . . .
1-12
1-12
1-13
1-15
1-22
1-24
Modeling an RF System
2
Modeling RF Components . . . . . . . . . . . . . . . . . . . . . . . . . .
Adding RF Blocks to a Simulink Model . . . . . . . . . . . . . . . .
Connecting Model Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-2
2-2
2-2
Specifying or Importing Component Data . . . . . . . . . . . .
2-6
v
Specifying Parameter Values . . . . . . . . . . . . . . . . . . . . . . . .
Importing Data Files into RF Blocks . . . . . . . . . . . . . . . . . .
Example — Importing a Touchstone Data File into an RF
Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Importing Circuits from the MATLAB Workspace . . . . . . .
Example — Importing a Bandstop Filter into an RF
Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Modeling Thermal Noise . . . . . . . . . . . . . . . . . . . . . . . . . . .
Amplifier and Mixer Noise Specifications . . . . . . . . . . . . . .
Adding Noise to Your System . . . . . . . . . . . . . . . . . . . . . . . .
Plotting Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-6
2-7
2-8
2-14
2-15
2-22
2-22
2-23
2-24
Plotting Model Data
3
Creating Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Validating Individual Blocks and Subsystems . . . . . . . . . .
Types of Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Plot Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How to Create a Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example — Plotting Component Data on a Z Smith
Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-15
Updating Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-19
...................................
3-20
Example — Creating and Modifying Subsystem
Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Plotting the Network Parameters of a Subsystem . . . . . . .
Adding Data to an Existing Plot . . . . . . . . . . . . . . . . . . . . .
Changing Data on an Existing Plot . . . . . . . . . . . . . . . . . . .
3-22
3-22
3-24
3-26
Modifying Plots
vi
Contents
3-2
3-2
3-3
3-4
3-9
Blocks — By Category
4
.....................................
4-2
Physical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ladder Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transmission Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Black Box Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Amplifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mixers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input/Output Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-3
4-3
4-3
4-4
4-4
4-5
4-5
Mathematical
Blocks — Alphabetical List
5
RF Blockset Algorithms
A
Simulating an RF Model . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A-2
Determining the Modeling Frequencies . . . . . . . . . . . . . .
A-3
Mapping Network Parameters to Modeling
Frequencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A-5
Modeling Noise in an RF System . . . . . . . . . . . . . . . . . . . .
Calculating Noise Figure at Modeling Frequencies . . . . . .
Calculating Output Noise Power . . . . . . . . . . . . . . . . . . . . .
A-7
A-8
A-9
Creating a Complex Baseband-Equivalent Model . . . . .
Baseband-Equivalent Modeling . . . . . . . . . . . . . . . . . . . . . .
Simulation Efficiency of a Complex Baseband-Equivalent
Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A-10
A-10
A-13
vii
Converting to and from Simulink Signals . . . . . . . . . . . .
A-15
Examples
B
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B-2
Index
viii
Contents
1
Getting Started
What Is the RF Blockset? (p. 1-2)
Introduces the RF Blockset and
describes its capabilities
Required and Related Products
(p. 1-3)
Describes products you can use to
extend the capabilities of the RF
Blockset
Product Demos (p. 1-4)
Describes how to access the RF
Blockset demos in the Help browser
RF Blockset Libraries (p. 1-6)
Summarizes the RF Blockset
libraries
RF Blockset Workflow (p. 1-10)
Describes a typical workflow
Example — Modeling an LC
Bandpass Filter (p. 1-12)
Describes how to build an RF model,
modify the parameters, run the
model in Simulink, and examine the
results
1
Getting Started
What Is the RF Blockset?
The RF Blockset extends Simulink® with a library of blocks for modeling RF
systems that include RF filters, transmission lines, amplifiers, and mixers.
For more information about creating and running Simulink models, see
“Building a Model” in the Simulink User’s Guide.
You use blocks from the RF Blockset to represent the components of your RF
system in a Simulink model. The blockset provides several types of component
representations using network parameters (S, Y, Z, ABCD, H, and T format),
mathematical descriptions, and physical properties.
In the Simulink model, you cascade the components to represent your RF
architecture and run the simulation. During the simulation, all blocks are
modeled using a time-domain, complex-baseband representation. This way
of modeling results in fast simulation and enables compatibility with other
Simulink blocks.
The RF Blockset lets you visualize the network parameters of the blocks
using plots and Smith charts.
A validated Simulink model of an RF system can provide an executable
specification for RF circuit design for wireless communication systems.
1-2
Required and Related Products
Required and Related Products
In addition to MATLAB and Simulink, you must have the following products
installed to use the RF Blockset:
• RF Toolbox — Provides MATLAB functions for defining, simulating, and
visualizing RF components.
• Signal Processing Toolbox — Provides MATLAB functions for filtering
wireless communication signals.
• Signal Processing Blockset — Provides Simulink blocks for time-domain
simulation of communication signals.
You can build sophisticated wireless communication system models by
incorporating blocks from other blocksets, such as the Signal Processing
Blockset and Communications Blockset.
The MathWorks provides several products that are especially relevant to the
kinds of tasks you can perform with the RF Blockset. The following table
summarizes the related products and describes how they complement the
features of the RF Blockset.
Product
Description
Communications Blockset
Simulink blocks for time-domain
simulation of modulation and
demodulation of a wireless
communications signal.
Communications Toolbox
MATLAB functions for signal
modulation and demodulation.
Filter Design Toolbox
MATLAB functions for filtering the
modulated communication signal.
1-3
1
Getting Started
Product Demos
You can find interactive RF Blockset demos in the MATLAB Help browser, as
shown in the following figure.
This example shows you how to locate and open an RF Blockset demo:
1 Type demos at the MATLAB prompt to open the Help browser to the
Demos tab.
2 Select Blocksets > RF in the Demos tab to see a list of demo categories.
3 Select a model, and click Open this model in the upper-right corner of the
demo window to display the Simulink model for this demo.
1-4
Product Demos
4 In the model window, select Simulation > Start to run the demo
simulation.
1-5
1
Getting Started
RF Blockset Libraries
The RF Blockset consists of the Physical and Mathematical libraries of
components for modeling RF systems within the Simulink environment.
An RF model can contain blocks from both the Physical and Mathematical
libraries. It can also include Simulink blocks and blocks from other
MathWorks blocksets, such as those described in “Required and Related
Products” on page 1-3.
This section contains the following topics:
• “Opening RF Blockset Libraries” on page 1-6
• “Physical Library” on page 1-7
• “Mathematical Library” on page 1-9
Opening RF Blockset Libraries
To open the main library window, type the following at the MATLAB prompt:
rflib
The window is shown in the following figure. Each yellow icon in the window
represents a library. Double-click an icon to open the corresponding library.
The Physical and Mathematical libraries are discussed in the following
sections.
1-6
RF Blockset Libraries
Note The blue icons take you to the MATLAB Help browser.
• Double-click the Demos icon to open the RF Blockset demos.
• Double-click the Info icon to open the RF Blockset documentation.
Physical Library
Use blocks from the Physical library to model physical and electrical
components by specifying physical properties or by importing measured
data. The Physical library includes several sublibraries, as shown in the
following figure.
The following table describes the sublibraries and how they can be used.
Sublibrary
Description
Amplifiers
RF amplifiers, specified using S-, Y-,
or Z-parameters, noise figure, and
IP3, or a data file containing these
parameters.
1-7
1
Getting Started
Sublibrary
Description
Ladder Filters
RF filters, specified using RLC
parameters. The network
parameters of the blocks are
calculated from the topology of the
filter and the RLC values.
Mixers
RF mixers that contain local
oscillators, specified using S-, Y-,
or Z-parameters and phase noise,
or a data file containing these
parameters.
Transmission Lines
RF filters, specified using
physical dimensions and electrical
characteristics.
Black Box
Passive RF components, specified
using S-, Y-, or Z-parameters,
or a data file containing these
parameters.
Input/Output Ports
Blocks for specifying simulation
information that pertains to all
blocks in a physical subsystem, such
as center frequency and sample time.
Note A physical subsystem is a
collection of one or more physical
blocks bracketed by an Input
Port block and an Output Port
block that bridge the physical and
mathematical parts of the model.
For more information on defining components, see “Specifying or Importing
Component Data” on page 2-6.
1-8
RF Blockset Libraries
Mathematical Library
The Mathematical library contains mathematical representations of the
amplifier, mixer, and filter blocks. Use a block from the Mathematical library
to model an RF component in terms of mathematical equations that describe
how the block operates on an input signal.
Note Mathematical blocks assume perfect impedance matching and a
nominal impedance of 1 ohm. In contrast, the physical blocks do not assume
perfect matching—these blocks model the reflections that occur between
blocks, and you can specify the source and load impedances using the Input
Port and Output Port blocks.
The mathematical library is shown in the following figure.
1-9
1
Getting Started
RF Blockset Workflow
When you analyze an RF system using the RF Blockset, your workflow might
include the following tasks:
1 Create a Simulink model of RF components.
For more information , see “Modeling RF Components” on page 2-2.
2 Define component data by
• Specifying network parameters, mathematical relationships, or physical
properties
• Importing data from an industry-standard Touchstone file, a MathWorks
AMP file, or the MATLAB workspace
The RF Blockset lets you access component data in Touchstone SnP,
YnP, ZnP, and HnP formats. You can also import amplifier network
parameters and power data from a MathWorks AMP file.
For more information, see “Specifying or Importing Component Data” on
page 2-6.
3 Add thermal noise to the system.
For more information, see “Modeling Thermal Noise” on page 2-22.
4 Validate the behavior of individual blocks by plotting component data.
Note You can plot data for individual blocks from the RF Physical library
that model physical components either before or after you run a simulation.
For more information, see “Creating Plots” on page 3-2.
5 Run the simulation.
For more information on how the RF Blockset performs time-domain
simulation of an RF system, see “Simulating an RF Model” on page A-2.
6 Generate plots to gain insight into system behavior.
1-10
RF Blockset Workflow
For more information, see “Creating Plots” on page 3-2.
The following plots and charts are available in the RF Blockset:
• Rectangular plots
• Polar plots
• Smith charts
• Composite plots
• Budget plots
1-11
1
Getting Started
Example — Modeling an LC Bandpass Filter
In this example, you model the signal attenuation caused by an RF filter by
comparing the signals at the input and output of the filter.
The RF filter you use in this example is an LC bandpass filter with a
bandwidth of 200 MHz, centered at 700 MHz. You use a three-tone input
signal to stimulate a range of in-band and out-of-band frequencies of the filter.
The input signal has the following tones:
• 700 MHz — Center of the filter
• 600 MHz — Lower edge of the filter passband
• 900 MHz — Outside the filter passband
You simulate the effects of the filter over a bandwidth of 500 MHz.
This example illustrates how to perform the following tasks:
• “Selecting Blocks to Represent System Components” on page 1-12
• “Building the Model” on page 1-13
• “Specifying Model Parameters” on page 1-15
• “Validating Filter Components and Running the Simulation” on page 1-22
• “Analyzing the Simulation Results” on page 1-24
Selecting Blocks to Represent System Components
In this part of the example, you select the blocks to represent the input signal,
the RF filter, and the signal displays.
You model the RF filter using a physical subsystem, which is a collection of one
or more physical blocks bracketed by an Input Port block and an Output Port
block. The RF filter subsystem consists of an LC Bandpass Pi block, and the
Input Port and Output Port blocks. The function of the Input Port and Output
Port blocks is to bridge the physical and mathematical parts of the model.
The following table lists the blocks that represent the RF system components
and a description of the role of each block.
1-12
Example — Modeling an LC Bandpass Filter
Block
Description
Sine Wave
Generates a three-channel signal.
Matrix Sum
Combines the three channel signal into a single
three-tone source signal.
Input Port
Establishes parameters that are common to all
blocks in the RF filter subsystem, including the
source impedance of the subsystem that is used to
convert Simulink signals to the RF Blockset physical
modeling environment.
LC Bandpass Pi
Models the signal attenuation caused by the RF filter
which, in this example, is the LC Bandpass Pi filter.
Output Port
Establishes parameters that are common to all
blocks in the RF filter subsystem. These parameters
include the load impedance of the subsystem, which
is used to convert RF signals to Simulink signals.
Spectrum Scope
Displays signals at the input to and output of the
filter.
Building the Model
In this part of the example, you create a Simulink model, add blocks to the
model, and connect the blocks.
1 Create a Simulink model.
If you are new to Simulink, see the introductory Simulink example,
“Building a Model”, for information on how to create a Simulink model.
2 Add to the model the blocks shown in the following table. The Library
column of the table specifies the hierarchical path to each block.
1-13
1
1-14
Getting Started
Block
Library Path
Quantity
Sine Wave
Signal Processing Blockset > Signal
Processing Sources
1
Matrix Sum
Signal Processing Blockset > Math
Functions > Matrices and Linear
Algebra > Matrix Operations
1
Spectrum Scope
Signal Processing Blockset > Signal
Processing Sinks
2
Input Port
RF Blockset >
Physical > Input/Output Ports
1
LC Bandpass Pi
RF Blockset > Physical > Ladder
Filters
1
Output Port
RF Blockset >
Physical > Input/Output Ports
1
Example — Modeling an LC Bandpass Filter
3 Connect the blocks as shown in the following figure.
For more information on connecting physical and mathematical blocks, see
“Connecting Model Blocks” on page 2-2.
Now you are ready to specify block parameters.
Specifying Model Parameters
In this part of the example, you specify the following parameters to represent
the behavior of the system components:
• “Input Signal Parameters” on page 1-15
• “Filter Subsystem Parameters” on page 1-18
• “Signal Display Parameters” on page 1-21
Input Signal Parameters
You generate the three-tone source signal using two blocks. You use the Sine
Wave block to build a complex three-channel signal, where each channel
1-15
1
Getting Started
corresponds to a different frequency. Then, you use the Matrix Sum block to
combine the channels into a single three-tone source signal.
The algorithm used by the RF Blockset requires you to shift the frequencies
of the input signal. The RF Blockset simulates the filter subsystem using a
complex-baseband modeling technique, which shifts the filter response so it
is centered at zero. You must shift the frequencies of the signals outside the
physical subsystem by the same amount.
For more information on complex-baseband modeling, see “Creating a
Complex Baseband-Equivalent Model” on page A-10.
Note The RF Blockset requires that all signals in the RF model be complex
to match the signals in the physical subsystem, so you create a complex
input signal.
The center frequency of the LC bandpass filter is 700 MHz, so you use a
three-tone source signal with tones that are 700 MHz below the actual tones,
at -100 MHz, 0 MHz, and 200 MHz, respectively.
1 Set the Sine Wave block parameters as follows:
• Amplitude = 1e-6
• Frequency (Hz) = [-100 0 200]*1e6
• Output complexity = Complex
• Sample time = 1/500e6
1-16
Example — Modeling an LC Bandpass Filter
• Samples per frame = 128
1-17
1
Getting Started
2 Set the Matrix Sum block Sum along parameter to Rows.
Filter Subsystem Parameters
In this part of the example, you configure the blocks that model the RF filter
subsystem—the Input Port, LC Bandpass Pi, and Output Port blocks.
1 Set the Input Port block parameters as follows:
• Center frequency = 700e6
• Sample time(s) = 1/500e6
1-18
Example — Modeling an LC Bandpass Filter
• Clear the Add noise check box so the RF Blockset will not include
thermal noise in the simulation. To learn how to model thermal noise,
see “Modeling Thermal Noise” on page 2-22.
Note You must enter the Sample time (s) because the Input Port block
does not inherit a sample time from the input signal. The specified sample
time must match the sample time of the input signal. The Sample time
(s) of 1/500e6 second used in this example is equivalent to a bandwidth
of 500 MHz.
1-19
1
Getting Started
2 Accept default parameters for inductance and capacitance in the LC
Bandpass Pi block. These parameters create a filter with the desired
bandwidth of 200 MHz, centered at 700 MHz.
1-20
Example — Modeling an LC Bandpass Filter
3 Accept the default parameters for the Output Port block to use a load
impedance of 50 ohms.
Signal Display Parameters
In this part of the example, you specify the parameters of the Spectrum Scope
block to display the source signal, and the parameters of the Spectrum Scope1
block to display the filtered signal.
For each scope, you set the range of the X- and Y-axes to make sure that the
entire signal is visible.
By default, the scope displays appear stacked on top of each other on the
screen when you run the simulation, so you can only see one of them. To
ensure that both scopes are visible during the simulation, you specify a
different position for each scope on the screen.
1 Set the Spectrum Scope block parameters as follows:
• Axis Properties pane, Frequency range = [-Fs/2...Fs/2]
• Axis Properties pane, Minimum Y-limit = -160
• Axis Properties pane, Maximum Y-limit = -100
• Display Properties pane, Scope position =
get(0,'defaultfigureposition').*[.15 1 1 1]
1-21
1
Getting Started
2 Set the Spectrum Scope1 block parameters as follows:
• Axis Properties pane, Frequency range = [-Fs/2...Fs/2]
• Axis Properties pane, Minimum Y-limit = -160
• Axis Properties pane, Maximum Y-limit = -105
• Display Properties pane, Scope position =
get(0,'defaultfigureposition').*[1.85 1 1 1]
Note If you do not specify the Display Properties of the scopes, you can
click and drag the displays to arrange them on the screen after the simulation
starts.
Validating Filter Components and Running the
Simulation
In this part of the example, you validate the behavior of the LC Bandpass Pi
filter block by plotting its network parameters and then run the simulation.
Note When you plot information about a physical block, the plot displays
the actual frequency response of the block at the selected passband (i.e.
the response at the unshifted frequencies), and not the response at the
shifted frequencies. Recall that this shift was introduced in “Input Signal
Parameters” on page 1-15.
1 Double-click the LC Bandpass Pi block to open the block dialog box.
1-22
Example — Modeling an LC Bandpass Filter
2 Select the Plot the selected parameters of this block check box. Click
Apply to plot the frequency response of the filter. This plots the magnitude
of S21 as a function of frequency, which represents the gain of the filter.
Filter Gain
Note The physical blocks only model a band of frequencies around the
center frequency of the physical subsystem. You must choose the sample
time and center frequency such that all important frequency characteristics
of your physical subsystem fall in this band of frequencies. The plot shows
the frequency response of the filter for the portion of the RF spectrum that
the physical blocks model. In this example, the physical blocks model a 500
MHz band that is centered at 700 MHz, defined by the Input Port block.
1-23
1
Getting Started
3 In the Simulink model window, select Simulation > Start to run the
simulation.
Analyzing the Simulation Results
In this part of the example, you analyze the results of the simulation. This
section contains the following topics:
• “Comparing the Input and Output Signals of the RF Filter” on page 1-24
• “Plotting Model Parameters of the Filter Subsystem” on page 1-27
Comparing the Input and Output Signals of the RF Filter
You can view the source signal and the filtered signal in the Spectrum Scope
windows while the model is running. These windows appear automatically
when you start the simulation.
1-24
Example — Modeling an LC Bandpass Filter
The following plot shows the RF filter input signal you specified in the Sine
Wave block.
Display block name
-101 dB
Input to RF Filter
1-25
1
Getting Started
The next plot shows the filtered signal. Notice that the amplitude of the peaks
is attenuated as a result of the RF filter.
-107 dB
Attenuated Output of RF Filter
Together, the Input Port and Output Port blocks introduce a 6-dB attenuation
into the physical system at all frequencies. You can see this loss in the plots
by comparing the input and output signals at the center frequency of the
filter. The magnitude of the input signal at the center frequency approaches
-101 dB in the Spectrum Scope window. The magnitude of the output signal
at the center frequency approaches -107 dB in the Spectrum Scope1 window.
However, as shown in the plot in the previous section, Filter Gain on page
1-23, the filter does not attenuate the signal at the center frequency. The
6 dB of loss is caused by the source and the load in the model. For more
1-26
Example — Modeling an LC Bandpass Filter
information on why this loss occurs, see the note in “Converting to and from
Simulink Signals” on page A-15.
Plotting Model Parameters of the Filter Subsystem
After you simulate an RF model, you can evaluate the behavior of the physical
subsystem by plotting the network parameters of the Output Port block.
Note When you plot information about a physical subsystem, the plot
displays the actual frequency response of the subsystem at the selected
passband (i.e. the response at the unshifted frequencies), and not the response
at the shifted frequencies.
To understand the frequency response of the filter, examine the S-parameters
as a function of frequency for the RF filter subsystem on a composite plot.
1 Open the dialog box of the Output Port block by double-clicking the block.
2 Select the Plot the model parameters of this block check box, and
click Apply.
The composite plot, shown in the following figure, contains four separate
plots in one figure. For the Output Port block, the composite plot shows the
following as a function of frequency (counterclockwise from the upper-left
plot):
• An X-Y plane plot of the magnitude of the filter gain, S21, in decibels.
• An X-Y plane plot of the phase of the filter gain, S21, in degrees.
• A Z Smith chart showing the real and imaginary parts of the filter
reflection coefficient, S11.
• A Polar plane plot showing the magnitude and phase of the filter reflection
coefficient, S11.
1-27
1
1-28
Getting Started
X-Y Plot,
Magnitude of S21
Polar Plot, S11
X-Y Plot,
Phase of S21
Z Smith Chart, S11
2
Modeling an RF System
Modeling RF Components (p. 2-2)
Describes how to add and connect
blocks in a Simulink model to
represent RF components
Specifying or Importing Component
Data (p. 2-6)
Describes how to define block
behavior by entering parameter
values and importing file and
workspace data
Modeling Thermal Noise (p. 2-22)
Explains how to model thermal noise
in a physical system
2
Modeling an RF System
Modeling RF Components
The RF Blockset lets you model an RF system using Simulink. This section
describes how to build a system model that incorporates RF components and
contains the following topics:
• “Adding RF Blocks to a Simulink Model” on page 2-2
• “Connecting Model Blocks” on page 2-2
Adding RF Blocks to a Simulink Model
You can include blocks from the RF Blockset Physical and Mathematical
libraries in a Simulink model. For more information on the libraries and the
available RF blocks, see “RF Blockset Libraries” on page 1-6.
To add RF blocks to a Simulink model:
1 Type rflib at the MATLAB prompt to open the RF Blockset library.
2 Navigate to the desired library or sublibrary.
3 Drag instances of RF Blockset blocks into the model window using the
mouse.
Note You can also access RF Blockset blocks and other Simulink blocks from
the Simulink Library Browser window. Open this window by typing simulink
at the MATLAB prompt. Add blocks to the model by dragging them from this
window and dropping them into the model window.
Connecting Model Blocks
You follow the same procedure for connecting RF Blockset blocks as for
connecting Simulink blocks: you click a port and drag the mouse to draw a
line to another port on a different block. For more information on connecting
Simulink blocks, see “Connecting the Blocks” in the Simulink documentation.
You can only connect blocks that use the same type of signal. RF Blockset
Physical blocks use different types of signals than Mathematical blocks, and
2-2
Modeling RF Components
are represented graphically by a different port style. Therefore, you can freely
connect pairs of Mathematical modeling blocks. You can also freely connect
pairs of Physical modeling blocks. However, you cannot directly connect
Physical blocks to Mathematical blocks. Instead, you must use the Input Port
and Output Port blocks to bridge them.
For more information on the RF Blockset libraries, including how to open the
libraries and a description of the available blocks, see “RF Blockset Libraries”
on page 1-6.
This section contains the following topics:
• “Connecting Mathematical Blocks” on page 2-3
• “Connecting Physical Blocks” on page 2-4
• “Bridging Physical and Mathematical Blocks” on page 2-4
Connecting Mathematical Blocks
The RF Blockset Mathematical blocks use the same input and output ports as
standard Simulink blocks. These ports show the direction of the signal at the
port, as shown in the following diagram.
RF Blockset mathematical
modeling ports show signal
direction
Similar to standard Simulink blocks, you draw lines between the ports of the
Mathematical modeling blocks, called signal lines, to represent signals that
are inputs to and outputs from the mathematical functions represented by
the blocks. Therefore, you can connect Simulink, Signal Processing, and RF
Blockset mathematical blocks by drawing signal lines between their ports.
You can connect a port to multiple ports by branching the signal line, or you
can leave a port unconnected. For more information on connecting Simulink
blocks, see “Connecting the Blocks” in the Simulink documentation.
2-3
2
Modeling an RF System
Connecting Physical Blocks
The RF Blockset Physical blocks have specialized connector ports. These ports
only represent physical connections; they do not imply signal direction.
RF Blockset physical modeling
connector ports represent only
physical connections.
The lines you draw between the RF Blockset physical modeling blocks, called
connection lines, represent physical connections among the block components.
Connection lines appear as solid black when connected and as dashed red
lines when either end is unconnected.
You can draw connection lines only between the connector ports of physical
modeling blocks. You cannot branch these connection lines. You cannot leave
connector ports unconnected.
Bridging Physical and Mathematical Blocks
The RF Blockset provides the Input Port and Output Port blocks to connect
the physical and mathematical parts of the model. These blocks convert
mathematical signals to and from the physical modeling environment.
The Input Port and Output Port blocks have one of each kind of connector
port: a standard Simulink style input port and a physical modeling port.
These ports are shown in the following figure:
Mathematical, or Simulink style, ports
Physical Modeling Ports
The Input Port and Output Port blocks must bound a physical subsystem to
connect it to the mathematical part of a model.
2-4
Modeling RF Components
For example, a simple RF model of a coaxial transmission line might resemble
the following figure.
The Microstrip Transmission Line block uses an Input Port block to get its
white noise input from a Random Source block, and an Output Port block to
pass its output to a Spectrum Scope block. The Random Source and Spectrum
Scope blocks are from Signal Processing Blockset library.
For information on how the RF Blockset converts mathematical signals to
and from the physical modeling environment, see “Converting to and from
Simulink Signals” on page A-15.
2-5
2
Modeling an RF System
Specifying or Importing Component Data
You can specify RF Blockset blocks by entering the RF component parameter
values. The RF Blockset also lets you import
• Industry-standard file formats — Touchstone S2P, Y2P, Z2P, and H2P
formats specify the network parameters and noise information for
measured and simulated data.
For more information on Touchstone files, see
http://www.vhdl.org/pub/ibis/connector/touchstone_spec11.pdf.
• MathWorks amplifier (AMP) file format — Specifies amplifier network
parameters, power data, noise data, and third-order intercept point
For more information about .amp files, see “AMP File Format” in the RF
Toolbox documentation.
• MATLAB circuits — RF Toolbox circuit objects in the MATLAB workspace
specify network parameters, noise data, and third-order intercept point
information of circuits with different topologies.
For more information about RF circuit objects, see the RF Toolbox rfckt
reference page.
This section contains the following topics:
• “Specifying Parameter Values” on page 2-6
• “Importing Data Files into RF Blocks” on page 2-7
• “Example — Importing a Touchstone Data File into an RF Model” on page
2-8
• “Importing Circuits from the MATLAB Workspace” on page 2-14
• “Example — Importing a Bandstop Filter into an RF Model” on page 2-15
Specifying Parameter Values
There are two ways to set block parameter values:
• Using the GUI — Enter information in the block dialog boxes, which open
when you double-click a block in the Simulink window.
2-6
Specifying or Importing Component Data
• Using commands — Use the Simulink set_param and get_param
commands to set and get parameter values of the blocks, respectively. For
more information on these commands, see the set_param and get_param
reference pages.
Importing Data Files into RF Blocks
The RF Blockset lets you import industry-standard data files and MathWorks
AMP files into specific blocks to simulate the behavior of measured
components in Simulink.
This section contains the following topics:
• “Blocks Used to Import Data” on page 2-7
• “How to Import Data Files” on page 2-7
Blocks Used to Import Data
Three blocks in the Physical library accept data from a file. The following
table lists the blocks and any corresponding data format that each supports.
Block
Description
Supported Format(s)
General Amplifier
Generic amplifier
Touchstone, AMP
General Mixer
Generic mixer
Touchstone, AMP
General Passive
Network
Generic passive
component
Touchstone
How to Import Data Files
To import a data file:
1 Choose the block that best represents your component from the list of blocks
that accept file data shown in“Blocks Used to Import Data” on page 2-7.
2 Open the RF Blockset Physical library, and navigate to the sublibrary that
contains the block.
3 Click and drag the block into your Simulink model.
2-7
2
Modeling an RF System
4 In the block dialog box, enter a value of read(rfdata.data, 'filename')
for the RFCKT object parameter, where filename is the name of your
data file.
This value specifies that the RF Toolbox read function reads data from
filename into an RF Toolbox data object. The RF Blockset uses this data
object to simulate the data. For more information on RF Toolbox data
objects, see the rfdata reference page.
RFDATA object
parameter value
This procedure is illustrated by example in the following section.
Example — Importing a Touchstone Data File into
an RF Model
In this example, you simulate the frequency response of a passive component
using data from a Touchstone file, passive.s2p.
2-8
Specifying or Importing Component Data
You use a model from one of the RF Blockset demos to perform the following
tasks:
• “Importing Data into a General Passive Network Block” on page 2-9
• “Validating the Passive Component” on page 2-11
• “Running the Simulation and Analyzing the Results” on page 2-13
Importing Data into a General Passive Network Block
In this part of the example, you inspect the passive.s2p file and import data
into the RF model using the General Passive Network block.
1 Type the following at the MATLAB prompt to open the passive.s2p file:
edit passive.s2p
The following figure shows a portion of the .s2p file.
2-9
2
Modeling an RF System
The option line
# Hz S DB R 50
specifies the following information about the contents of the data file:
• Hz — Frequency units.
• S — Network parameters are S-parameters.
• DB — Network parameters are specified as magnitude in dB and phase
in degrees.
• R 50 — Reference impedance is 50 ohms.
For more information about the Touchstone
specification, including the option line, see
http://www.vhdl.org/pub/ibis/connector/touchstone_spec11.pdf.
2 At the MATLAB prompt, type
sparam_filter
This opens the RF Blockset demo called “Touchstone Data File for 2-Port
Passive Networks.”
2-10
Specifying or Importing Component Data
3 Double-click the General Passive Network block to display its parameters.
The RFDATA object parameter specifies the data file to import.
The RFDATA object parameter is set to read(rfdata.data,
'passive.s2p'). This setting reads the data from the file passive.s2p
into an rfdata.data object. The block uses this data with the other block
parameters during simulation.
Note When the imported file contains data that is measured at frequencies
other than the modeling frequencies, use the Interpolation method
parameter to specify how the block determines the data values at the
modeling frequencies. For more information, see“Determining the Modeling
Frequencies” on page A-3 and “Mapping Network Parameters to Modeling
Frequencies” on page A-5.
Validating the Passive Component
In this part of the example, you plot the network parameters of the General
Passive Network block to validate the data you imported in “Importing Data
into a General Passive Network Block” on page 2-9.
1 Open the General Passive Network block dialog box, and perform the
following actions:
a Select the Plot the selected parameters of this block check box.
b Set the Parameter parameter to S11.
c Click Apply.
2-11
2
Modeling an RF System
These dialog box selections create a plot of S11 as a function of frequency.
S11 versus Frequency for the Imported Data
2 Open the General Passive Network block dialog box, set the Parameter
parameter to S21, and click Apply.
2-12
Specifying or Importing Component Data
The block adds the S21 data to the plot.
S11 and S21 versus Frequency for the Imported Data
Running the Simulation and Analyzing the Results
In this part of the example, you run the simulation and examine the frequency
response of the passive component.
Start the simulation by selecting Simulation > Start in the Simulink model
window. This action opens the Vector scope plot, which displays the amplitude
of the transfer function of the system in decibels as a function of frequency, as
shown in the following figure:
2-13
2
Modeling an RF System
Transfer Function of General Passive Network Subsystem
Note The transfer function differs from S21. The differences arise from
the following factors:
• The 6 dB of loss introduced by the source and the load in the sparam_filter
model. This loss is described in the note in “Converting to and from
Simulink Signals” on page A-15.
• The numerical error introduced by the calculation of the transfer function.
Importing Circuits from the MATLAB Workspace
You can only connect the RF Blockset Physical blocks in cascade. However, the
RF Blockset works with the RF Toolbox to let you include additional circuit
topologies in an RF model. To model circuit topologies that contain other
types of connections, you must define a circuit in the MATLAB workspace and
import it into an RF model.
To import a circuit from the MATLAB workspace:
2-14
Specifying or Importing Component Data
1 Define the circuit object in the MATLAB workspace using the RF Toolbox
functions.
For more information about RF circuit objects, see the RF Toolbox rfckt
reference page.
2 Add a General Circuit Element block to your RF model from the Black Box
Elements sublibrary of the Physical library. For information on how to open
this library, see “Opening RF Blockset Libraries” on page 1-6.
3 Enter the circuit object name in the RFCKT object parameter in the
General Circuit Element block dialog box.
This procedure is illustrated by example in the following section.
Example — Importing a Bandstop Filter into an RF
Model
In this example, you simulate the frequency response of a filter that you
model using circuit objects from the MATLAB workspace.
The filter in this example is the 50-ohm bandstop filter shown in the following
figure.
Bandstop Filter Diagram
2-15
2
Modeling an RF System
You represent the filter using four circuit objects that correspond to the
four parts of the filter, ckt1, ckt2, ckt3, and ckt4 in the diagram. You use
an input signal with random, complex input values that have a Gaussian
distribution to stimulate the filter. The scope block displays the output signal.
This example illustrates how to perform the following tasks:
• “Creating Circuit Objects in the MATLAB Workspace” on page 2-16
• “Building the Model” on page 2-17
• “Specifying and Importing Component Data” on page 2-18
• “Running the Simulation and Plotting the Results” on page 2-20
Creating Circuit Objects in the MATLAB Workspace
In this part of the example, you define MATLAB variables to represent the
physical properties of the filter shown in the previous figure, Bandstop Filter
Diagram on page 2-15, and use RF Toolbox functions to create RF circuit
objects that model the filter components.
1 Type the following at the MATLAB prompt to define the filter’s resistance,
capacitance, and inductance values in the MATLAB workspace:
C1
C2
C3
C4
C5
C6
L1
L2
L3
L4
L5
L6
2-16
=
=
=
=
=
=
=
=
=
=
=
=
1.734e-12;
4.394e-12;
7.079e-12;
7.532e-12;
1.734e-12;
4.394e-12;
25.70e-9;
3.760e-9;
17.97e-9;
3.775e-9;
17.63e-9;
25.70e-9;
Specifying or Importing Component Data
2 Type the following at the MATLAB prompt to create RF circuit objects
that model the components labeled ckt1, ckt2, ckt3, and ckt4 in the
circuit diagram:
ckt1 =
rfckt.series('Ckts',{rfckt.shuntrlc('C',C1),rfckt.shuntrlc('L'
,L1,'C',C2)});
ckt2 =
rfckt.parallel('Ckts',{rfckt.seriesrlc('L',L2),rfckt.seriesrlc
('L',L3,'C',C3)});
ckt3 =
rfckt.parallel('Ckts',{rfckt.seriesrlc('L',L4),rfckt.seriesrlc
('L',L5,'C',C4)});
ckt4 =
rfckt.series('Ckts',{rfckt.shuntrlc('C',C5),rfckt.shuntrlc('L'
,L6,'C',C6)});
For more information about the RF Toolbox functions used in this
example, see the rfckt.series, rfckt.parallel, rfckt.shuntrlc,
and rfckt.seriesrlc function reference pages in the RF Toolbox
documentation.
Building the Model
In this portion of the example, you create a Simulink model. For more
information about adding and connecting components, see “Modeling RF
Components” on page 2-2.
1 Create a new Simulink model.
2 Add to the model the blocks shown in the following table. The Library
column of the table specifies the hierarchical path to each block.
Block
Library
Quantity
Random Source
Signal Processing
Blockset > Signal Processing
Sources
1
2-17
2
Modeling an RF System
Block
Library
Quantity
Input Port
RF Blockset > Physical >
Input/Output Ports
1
General Circuit
Element
RF Blockset > Physical > Black
Box Elements
4
Output Port
RF Blockset > Physical >
Input/Output Ports
1
Spectrum Scope
Signal Processing
Blockset > Signal Processing
Sinks
1
3 Connect the blocks as shown in the following figure.
Change the names of your General Circuit Element blocks to match those
in the figure by double-clicking the text below the block and typing a new
name.
Specifying and Importing Component Data
In this portion of the example, you specify block parameters. To open the
parameter dialog box for each block, double-click the block.
2-18
Specifying or Importing Component Data
1 Set the Random Source block parameters as follows:
• Source type = Gaussian
• Sample time = 1/(100e6)
• Samples per frame = 256
• Complexity = Complex
Selecting these settings creates an input signal with random, complex
input values that have a Gaussian distribution.
2 Set the Input Port block parameters as follows:
• Finite impulse response filter length = 256
• Center frequency (Hz) = 400e6
• Sample time = 1/(100e6)
• Source impedance = 50
• Clear the Add noise check box.
Selecting these settings defines the physical characteristics and modeling
bandwidth of the filter.
3 Set the parameters of the General Circuit Element blocks as follows:
• In the General Circuit Element1 block dialog box, set the RFCKT
object parameter to ckt1.
• In the General Circuit Element2 block dialog box, set the RFCKT
object parameter to ckt2.
• In the General Circuit Element3 block dialog box, set the RFCKT
object parameter to ckt3.
• In the General Circuit Element4 block dialog box, set the RFCKT
object parameter to ckt4.
Selecting these settings imports the circuit objects that model the filter
components into the Simulink model.
4 Type 50 in the Load impedance field of the Output Port block to represent
an impedance of 50 ohms.
2-19
2
Modeling an RF System
5 Set the Spectrum Scope block parameters as follows:
• On the Scope Properties pane, set the Number of spectral averages
parameter to 100.
This parameter establishes the number of spectra that the scope
averages to produce the displayed signal. You use a value of 100 because
the input signal is random and you want to display the average filter
response over a large number of input values.
• On the Axis Properties pane, set the Frequency range parameter to
[-Fs/2 ... Fs/2], the Minimum Y-limit parameter to -35, and the
Maximum Y-limit parameter to 3.6.
These values set the range of X- and Y-values on the display such that
the entire signal is visible when you run the simulation.
Running the Simulation and Plotting the Results
In this part of the example, you run the simulation and examine the frequency
response of the filter.
Select Simulation > Start in the Simulink model window to start the
simulation.
2-20
Specifying or Importing Component Data
The Spectrum Scope window appears automatically and displays the following
plot, which shows the frequency response of the filter.
Frequency Response of Bandstop Filter
References
Geffe, P.R., “Novel designs for elliptic bandstop filters,” RF Design, February
1999.
2-21
2
Modeling an RF System
Modeling Thermal Noise
The RF Blockset lets you include the thermal noise generated by any physical
block in your RF model. You only need to specify noise information for the
physical amplifier and mixer blocks that generate noise other than resistor
noise. For the other blocks, the RF Blockset calculates the noise automatically
based on the resistor values.
This section contains the following topics:
• “Amplifier and Mixer Noise Specifications” on page 2-22
• “Adding Noise to Your System” on page 2-23
• “Plotting Noise” on page 2-24
Amplifier and Mixer Noise Specifications
You specify noise for the physical amplifier and mixer blocks as spot noise
data or as noise figure values. The following table summarizes the noise
specification options for each type of physical amplifier and mixer block.
2-22
Block
Noise Specification
General Amplifier
Spot noise data (using a Touchstone
or AMP data file) or noise figure
values
S-Parameters Amplifier
Noise figure values
Y-Parameters Amplifier
Noise figure values
Z-Parameters Amplifier
Noise figure values
General Mixer
Spot noise data (using a Touchstone
or AMP data file) or noise figure
values
S-Parameters Mixer
Noise figure values
Y-Parameters Mixer
Noise figure values
Z-Parameters Mixer
Noise figure values
Modeling Thermal Noise
Adding Noise to Your System
To simulate the thermal noise of a physical subsystem, you perform the
following tasks:
• “Specifying or Importing Noise Data” on page 2-23
• “Adding Noise to the Simulation” on page 2-24
Specifying or Importing Noise Data
The method you use to add noise data to a block depends on whether you
are specifying noise figure or importing spot-noise data. The following table
provides instructions for adding noise data.
Noise Specification
Instructions
Noise figure
Enter the noise figure value in the
Noise figure (dB) parameter in the
block dialog box.
Spot noise data
Import file data that includes noise
information into the RFCKT object
parameter of the General Amplifier
or General Mixer block.
Note If you import file data with no noise information into a General
Amplifier or General Mixer block, the RF Blockset adds the Noise figure
(dB) parameter to the block dialog box . This parameter lets you specify
noise manually.
2-23
2
Modeling an RF System
Adding Noise to the Simulation
To include noise in the simulation, you must select the Add noise check box
on the Input Port block dialog box. This check box is selected by default.
Select this check box to
take the noise data in
the physical blocks into
account. This check box
is selected by default.
For information on how the RF Blockset simulates thermal noise, see
“Modeling Noise in an RF System” on page A-7.
Plotting Noise
The RF Blockset models communications systems. The noise in these systems
has a very small amplitude, typically from 1e-6 to 1e-12 Watts. In contrast,
the default signal power of a Communications Blockset modulator block is 1
Watt at a nominal 1 ohm. Therefore, the signal-to-noise ratio in an RF system
2-24
Modeling Thermal Noise
simulation is large, making it difficult to view the noise the RF Blockset adds
to your signal.
To display the noise on a plot, you might need to attenuate the signal
amplitude to a value within a couple orders of magnitude of the noise.
For example, suppose you have the following model that contains a multitone
test signal source.
2-25
2
Modeling an RF System
When you simulate this model, Simulink brings up several windows showing
the input and output for the physical subsystem. The Input - Frequency
Domain window shown in the following figure displays the input signal in
the frequency domain.
Input Signal Spectrum
2-26
Modeling Thermal Noise
The Real Part of Input - Time Domain window displays the real part of the
complex-valued input signal in the time domain.
Real Part of Input Signal
2-27
2
Modeling an RF System
In the model, the physical subsystem adds noise to the input signal. The
Output - Frequency Domain window shows the noisy output signal in the
frequency domain.
Output Signal Spectrum
2-28
Modeling Thermal Noise
The amplitude of the signal is large compared to the amplitude of the noise,
so the noise is not visible in the Real Part of Output - Time Domain window
that shows the real part of the time-domain output signal. Therefore, you
must attenuate the amplitude of the input signal to display the noise of the
time-domain output signal.
Real Part of Output Signal
2-29
2
Modeling an RF System
Attenuate the amplitude of the input signal by setting the Gain parameter
to 1e-3. This is equivalent to attenuating the input signal by 60 dB. When
you run the model again, the two signal peaks are not as pronounced in the
Output - Frequency Domain window.
Output Signal Spectrum for Attenuated Input
2-30
Modeling Thermal Noise
You can now view the noise the RF Blockset adds to your signal in the Real
Part of Output - Time Domain window.
Real Part of Output Signal Showing Noise
2-31
2
2-32
Modeling an RF System
3
Plotting Model Data
Creating Plots (p. 3-2)
Describes the available plots and
explains how to plot data for
components and subsystems
Updating Plots (p. 3-19)
Describes how to update existing
plots after changing model
parameters
Modifying Plots (p. 3-20)
Describes how to add data to a plot
and how to change the plot type,
format, and frequency range
Example — Creating and Modifying
Subsystem Plots (p. 3-22)
Shows how to plot RF subsystem
data, add data to the plot, and
change the plot type
3
Plotting Model Data
Creating Plots
The RF Blockset lets you validate the behavior of individual RF components
and physical subsystems in your model by plotting the following data:
• S-parameters
• Noise figure
• Output third-order intercept point
• Power data
• Phase noise
• Voltage standing-wave ratio
The following topics describe the RF Blockset plotting options, explain the
procedure for creating a plot, and illustrate this procedure with an example:
• “Validating Individual Blocks and Subsystems” on page 3-2
• “Types of Plots” on page 3-3
• “Plot Formats” on page 3-4
• “How to Create a Plot” on page 3-9
• “Example — Plotting Component Data on a Z Smith Chart” on page 3-15
Validating 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 gain insight
into 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
“Example — Creating and Modifying Subsystem Plots” on page 3-22. To
3-2
Creating Plots
learn about the available plots, see “Types of Plots” on page 3-3. For more
information about creating plots, see “How to Create a Plot” on page 3-9.
Types of Plots
The RF Blockset 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 Type
Plot Contents
X-Y Plane
(Rectangular) Plot
Parameters as a function of frequency, such as
• S-parameters
• Noise figure (NF)
• Voltage standing-wave ratio (VSWR)
• Output third-order intercept point (OIP3)
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” on page
3-7.
Polar Plane Plot
Magnitude and phase of S-parameters as a function
of frequency.
Smith Chart
Real and imaginary parts of S-parameters as
a function of frequency, used for analyzing the
reflections caused by impedance mismatch.
Composite Plot
Multiple plots and charts in one figure.
To learn how to create these plots, see “How to Create a Plot” on page 3-9.
3-3
3
Plotting Model Data
Plot Formats
When you create a plot from a block dialog box, you must specify the plot
Format.
Plot format
This plot option defines how the RF Blockset 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 format determines
whether the RF 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 RF
Blockset to compute and plot the real part of the selected parameter.
The following topics describe the available parameters and formats for each
plot type:
• “Composite Data” on page 3-5
• “X-Y Plane” on page 3-7
• “Link Budget” on page 3-7
• “Polar Plane Plots and Smith Charts” on page 3-9
3-4
Creating Plots
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 plot format—both are set automatically.
3-5
3
Plotting Model Data
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.
Block
Specified Data
Plot Contents
General
Amplifier or
General Mixer
Network
parameters
X-Y plot, magnitude of S12 and S21
in decibels
OR
X-Y plot, phase of S12 and S21 in
degrees
Network
parameters and
noise
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
Other Physical
block
X-Y plot, output power (Pout) in dBm
(decibels referenced to one milliwatt)
Network
parameters,
noise, and power
Z Smith chart, real and imaginary
parts of S11 and S22
Network
parameters
X-Y plot, magnitude of S12 and S21
in decibels
Note Only the
General Amplifier
and General
Mixer blocks
accept power and
noise data.
3-6
X-Y plot, magnitude of S12 and S21
in decibels
Polar plot, magnitude and phase of
S11 and S22
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
Creating Plots
X-Y Plane
You can plot any parameters that are relevant to your block on an X-Y plane
plot. The following table summarizes the parameters and formats for this
type of plot.
Parameter
Format
S11, S12, S21, S22
Magnitude (decibels)
Magnitude (linear)
Angle (degrees)
Real
Imaginary
VSWRIn, VSWROut
Magnitude (decibels)
Magnitude (linear)
OIP3 (Output Port block only)
dBm
W
mW
NF (Output Port block only)
Magnitude (decibels)
Magnitude (linear)
Pout (General Amplifier block with
dBm
dBW
W
mW
power data only)
Phase (General Amplifier block with
power data only)
Angle (degrees)
Angle (radians)
AM/AM (General Amplifier block with
power data only)
Magnitude (decibels)
Magnitude (linear)
AM/PM (General Amplifier block with
power data only)
Angle (degrees)
Angle (radians)
PhaseNoise (Mixer blocks only)
dBc/Hz
Link Budget
You use the Link budget plot to understand the individual contribution of
each block to a plotted parameter value in a physical subsystem with multiple
components between the Input Port and the Output Port blocks.
3-7
3
Plotting Model Data
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.
Input Port
Component
(Index = 1)
Component
(Index = 2)
...
Component
(Index = n)
Output Port
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.
Contributions to S21
from components
1, 2, and 3
Contributions to S21
from components
1 and 2
Contributions to S21
from component 1
Example — Link Budget Plot
The following table summarizes the parameters and formats that are
available for a link budget plot.
3-8
Creating Plots
Parameter
Format
S11, S12, S21, S22
Magnitude (decibels)
Magnitude (linear)
Angle (degrees)
Real
Imaginary
VSWRIn, VSWROut
Magnitude (decibels)
Magnitude (linear)
OIP3
dBm
W
mW
NF
Magnitude (decibels)
Magnitude (linear)
Polar Plane Plots and Smith Charts
You can use the RF Blockset to generate Polar plots and Smith charts. When
you select these plot types, you do not need to specify the plot format—it
is set automatically.
The following table describes the Polar plot and Smith chart options, as well
as the available parameters.
Plot Type
Parameter
Polar plane
S11, S12, S21, S22
Z Smith chart
S11, S22
Y Smith chart
S11, S22
ZY Smith chart
S11, S22
How to Create a Plot
1 Double-click the block to open the block dialog box. The following figure
shows the area of the dialog box where you specify plotting options.
3-9
3
Plotting Model Data
2 Select the Plot the selected parameters of this block check box to
display the plot options.
Select this check box
to display the plot
options
3 Select the Source of frequency data.
Select the source
of frequencies
at which to plot
block data
3-10
Creating Plots
This 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
data
Description
Blocks
Derived from Input
Port parameters
Modeling frequencies
derived from the Input
Port block parameters.
For information on
how the RF Blockset
computes the modeling
frequencies, see
“Determining the
Modeling Frequencies”
on page A-3.
All physical blocks
Vector of frequencies
that you enter.
All physical blocks
(Available after
running a simulation
or clicking the Update
Diagram button
User-specified
)
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].
3-11
3
Plotting Model Data
Source of frequency
data
Description
Blocks
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 not displayed.
You use the Phase
noise frequency
offset (Hz) block
parameter to specify
the frequency values
at which to plot block
data.
Same as the
Frequency parameter
3-12
Frequency values
specified in the
Frequency block
parameter.
S-Parameters
Passive Network,
Y-Parameters
Passive Network,
Z-Parameters
Passive Network,
S-Parameters
Amplifier,
Y-Parameters
Amplifier,
Z-Parameters
Amplifier,
S-Parameters Mixer,
Y-Parameters Mixer,
Creating Plots
Source of frequency
data
Description
Blocks
and Z-Parameters
Mixer
Extracted from
RFDATA object
Frequency values
imported into the
RFDATA object
block parameter. For
information about
rfdata objects, see the
RF Toolbox rfdata
reference page.
General Passive
Network, General
Amplifier, and General
Mixer
4 Select the Plot type.
Select the plot type
This is the type of plot. For a description of the options, see “Types of Plots”
on page 3-3.
3-13
3
Plotting Model Data
5 Select the Parameter.
Select the plot parameter
This is 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” on page 3-4.
6 Choose the Format.
Select the plot format
This is the format 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”
on page 3-4.
7 Click Apply.
3-14
Creating Plots
Note By default, the RF Blockset does not add a legend to some plots. To
display the plot legend, type legend show at the MATLAB prompt.
Example — Plotting Component Data on a Z Smith
Chart
In this example, you simulate the frequency response of an amplifier using
data from the default.amp AMP file.
Using a model from one of the RF Blockset demos, 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 RF Blockset demo
called “AMP Data File for Amplifier”.
3-15
3
Plotting Model Data
2 Double-click the General Amplifier block to display its parameters.
Notice that the RFDATA object parameter is set to read(rfdata.data,
'default.amp'). This value uses the RF Toolbox read function to import
data from the file default.amp into an rfdata.data object. The block uses
this data, along with the other block parameters, in simulation.
Note The General Amplifier block models the nonlinear amplifier
described by an rfdata.data object. See the RF Toolbox rfdata reference
page for information about rfdata objects.
See “AMP File Format” in the RF Toolbox documentation for information
about .amp files.
3-16
Creating Plots
3 Set the General Amplifier block parameters as follows:
• Select the Plot the selected parameters of this block check box.
• In the Plot type list, select Z Smith chart.
• In the Parameter list, select S22.
4 Click Apply.
3-17
3
Plotting Model Data
This action creates a Z Smith® chart of the S22 parameters using the
frequency data from the default.amp 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 “Data Cursor — Displaying Data Values
Interactively” in the MATLAB documentation for more information.
3-18
Updating Plots
Updating Plots
When you run a simulation, the RF Blockset continues to display any open
plots, but does not update the plots to reflect new simulation results. You
must update the subsystem plots after the simulation to display the behavior
of the revised subsystem.
Note You do not need to update the plots that represent individual RF
components, because the RF Blockset redraws these plots when you make
changes to the block parameters.
To update an existing subsystem plot:
1 Double-click the Output Port block to open the block dialog box.
2 Clear and select the Plot the selected parameters of this block check
box.
3 Click Apply.
3-19
3
Plotting Model Data
Modifying Plots
You can modify an existing plot by changing the plot options. The outcome
depends on the parameter you change.
The following table summarizes the results of changing the plot options.
Block Parameter
Plot Change
Source of frequency
data
Redraws plot using the new frequency data.
OR
Frequency range
Plot type
Redraws figure in the new plot type, with the
following considerations:
• If the current plot options are valid for the
new plot type, they retain their values.
Otherwise, they revert to their default values.
• If you change the Plot type to or from
Composite data, the RF Blockset draws the
new plot in a new figure and does not update
the existing figure.
3-20
Parameter
If the new parameter has the same independent
variable as the one on the plot, the RF Blockset
adds the new parameter to the existing plot.
Otherwise, it redraws the plot for the new
parameter and independent variable.
Format
Redraws plot using the new format.
Modifying Plots
To modify a plot:
1 Double-click the block to open the block dialog box.
Example Block Dialog Box Showing Plot Parameters
2 Change the plot options.
3 Click Apply.
3-21
3
Plotting Model Data
Example — Creating and Modifying Subsystem Plots
In this example, you perform the following tasks:
• “Plotting the Network Parameters of a Subsystem” on page 3-22
• “Adding Data to an Existing Plot” on page 3-24
• “Changing Data on an Existing Plot” on page 3-26
Plotting the Network Parameters of a Subsystem
In this part of the example, you open and run an RF Blockset demo that uses
file data to specify an amplifier in a physical subsystem. Then, you plot the
network parameters of the physical subsystem, which consists of the General
Amplifier, the Input Port, and the Output Port blocks.
1 Type sparam_amp at the MATLAB prompt to open the RF Blockset demo
called “AMP Data File for Amplifier”.
2 In the Simulink model window, select Simulation > Start to run the
simulation.
3 Double-click the Output Port block to open the block dialog box.
3-22
Example — Creating and Modifying Subsystem Plots
4 Set the Output Port block parameters as follows:
• Select the Plot the selected parameters of this block check box.
• In the Plot type list, select X-Y plane.
• In the Parameter list, select S21.
5 Click Apply.
3-23
3
Plotting Model Data
This action plots the magnitude of S21 (in decibels) as a function of
frequency on an X-Y plot.
S21 versus Frequency for a Physical Subsystem
Adding Data to an Existing Plot
In this part of the example, you add data to the plot you created in “Plotting
the Network Parameters of a Subsystem” on page 3-22.
1 Double-click the Output Port block to open the block dialog box.
2 Change the value of Parameter to S22.
3-24
Example — Creating and Modifying Subsystem Plots
3 Click Apply.
This action adds S22 to the plot.
S21 and S22 versus Frequency for a Physical Subsystem
3-25
3
Plotting Model Data
Changing Data on an Existing Plot
In this part of the example, you change the data on the plot you created in the
previous steps of the example by modifying the Plot type.
1 Double-click the Output Port block to open the block dialog box.
2 Change the value of Plot type to Polar plane, as shown in the following
figure.
Notice that the value of Parameter remains as S22, the last parameter
selected for the previous plot.
3 Click Apply.
3-26
Example — Creating and Modifying Subsystem Plots
This action creates a Polar plane plot of S22 as a function of frequency.
S22 versus Frequency for a Physical Subsystem
3-27
3
Plotting Model Data
4 In the Output Port block dialog box, change the Plot type to Composite
data to generate four plots in one figure. The parameters for the plots are
defined by the block, so the Parameter field becomes invisible.
3-28
Example — Creating and Modifying Subsystem Plots
The RF Blockset creates the plot in a new figure.
X-Y Plot,
Magnitude of
S12 (blue)
S21 (green)
Polar Plot
S11 (blue)
S22 (green)
X-Y Plot,
Phase of
S12 (blue)
S21 (green)
Z Smith Chart
S11 (blue)
S22 (green)
Composite Plot for a Physical Subsystem
3-29
3
3-30
Plotting Model Data
4
Blocks — By Category
Mathematical (p. 4-2)
Model RF components in terms of
mathematical equations.
Physical (p. 4-3)
Model RF components in terms of
physical properties or measured data
4
Blocks — By Category
Mathematical
4-2
Amplifier
Complex baseband model of
amplifier with noise
Bandpass RF Filter
Standard bandpass RF filters in
baseband-equivalent complex form
Bandstop RF Filter
Standard bandstop RF filters in
baseband-equivalent complex form
Highpass RF Filter
Standard highpass RF filters in
baseband-equivalent complex form
Lowpass RF Filter
Standard lowpass RF filters in
baseband-equivalent complex form
Mixer
Complex baseband model of mixer
with phase noise
Physical
Physical
Ladder Filters (p. 4-3)
Ladder filter blocks
Transmission Lines (p. 4-3)
Transmission line blocks
Black Box Elements (p. 4-4)
Black box elements blocks
Amplifiers (p. 4-4)
Amplifier blocks
Mixers (p. 4-5)
Mixer blocks
Input/Output Ports (p. 4-5)
Connector blocks
Ladder Filters
LC Bandpass Pi
Model LC bandpass pi network
LC Bandpass Tee
Model LC bandpass tee network
LC Bandstop Pi
Model LC bandstop pi network
LC Bandstop Tee
Model LC bandstop tee network
LC Highpass Pi
Model LC highpass pi network
LC Highpass Tee
Model LC highpass tee network
LC Lowpass Pi
Model LC lowpass pi network
LC Lowpass Tee
Model LC lowpass tee network
Series RLC
Model series RLC network
Shunt RLC
Model shunt RLC network
Transmission Lines
Coaxial Transmission Line
Model coaxial transmission line
Coplanar Waveguide Transmission
Line
Model coplanar waveguide
transmission line
Microstrip Transmission Line
Model microstrip transmission line
4-3
4
Blocks — By Category
Parallel-Plate Transmission Line
Model parallel-plate transmission
line
RLCG Transmission Line
Model RLCG transmission line
Transmission Line
Model general transmission line
Two-Wire Transmission Line
Model two-wire transmission line
Black Box Elements
General Circuit Element
Model two-port network described
by rfckt object
General Passive Network
Model two-port passive network
described by rfdata object
S-Parameters Passive Network
Model passive network using its
S-parameters
Y-Parameters Passive Network
Model passive network using its
Y-parameters
Z-Parameters Passive Network
Model passive network using its
Z-parameters
Amplifiers
4-4
General Amplifier
Model nonlinear amplifier described
by rfdata object
S-Parameters Amplifier
Model nonlinear amplifier using its
S-parameters
Y-Parameters Amplifier
Model nonlinear amplifier using its
Y-parameters
Z-Parameters Amplifier
Model nonlinear amplifier using its
Z-parameters
Physical
Mixers
General Mixer
Model mixer described by rfdata
object
S-Parameters Mixer
Model mixer using its S-parameters
Y-Parameters Mixer
Model mixer using its Y-parameters
Z-Parameters Mixer
Model mixer using its Z-parameters
Input/Output Ports
Input Port
Connection block from Simulink
environment to RF physical blocks
Output Port
Connection block from RF physical
blocks to Simulink environment
4-5
4
4-6
Blocks — By Category
5
Blocks — Alphabetical List
Amplifier
Purpose
Complex baseband model of amplifier with noise
Library
Mathematical
Description
The Amplifier block generates a complex baseband model of an amplifier
with thermal noise. It provides six methods for modeling nonlinearity
and three ways to specify noise.
Note This block assumes a nominal impedance of 1 ohm.
Modeling Nonlinearity
Specify the method of your choice using this parameter in the block
dialog box. The options for the Method parameter are
• Linear
• Cubic polynomial
• Hyperbolic tangent
• Saleh model
• Ghorbani model
• Rapp model
The linear method is implemented by a Gain block. The other nonlinear
methods are implemented by subsystems underneath the block’s mask.
Each subsystem has the same basic structure, as shown in the figure
below.
5-2
Amplifier
Application of Nonlinearity
All five subsystems for the nonlinear methods apply a memoryless
nonlinearity to the complex baseband input signal. Each one
1 Multiplies the signal by a gain factor.
2 Splits the complex signal into its magnitude and angle components.
3 Applies an AM/AM conversion to the magnitude of the signal,
according to the selected interpolation method, to produce the
magnitude of the output signal.
4 Applies an AM/PM conversion to the phase of the signal, according to
the selected interpolation method, and adds the result to the angle of
the signal to produce the angle of the output signal.
5 Combines the new magnitude and angle components into a complex
signal and multiplies the result by a gain factor, which is controlled
by the Linear gain parameter.
AM/AM and AM/PM Conversions
The subsystems for the nonlinear methods implement the AM/AM and
AM/PM conversions differently, according to the interpolation method
you specify. To see exactly how the Amplifier block implements the
conversions for a specific method, you can view the AM/AM and AM/PM
subsystems that implement these conversions as follows:
1 Right-click the Amplifier block.
5-3
Amplifier
2 Select Look under mask in the pop-up menu. This displays the
block’s configuration underneath the mask. The block contains five
subsystems corresponding to the five nonlinearity methods.
3 Double-click the subsystem for the method in which you are
interested. A subsystem displays similar to the one shown in the
preceding figure.
4 Double-click one of the subsystems labeled AM/AM or AM/PM to view
how the block implements the conversions.
The following figure shows, for the Saleh method, plots of
• Output voltage against input voltage for the AM/AM conversion
• Output phase against input voltage for the AM/PM conversion
5-4
Amplifier
Effects of the Amplifier Block
You can see the effect of the Amplifier block in the demo
Intermodulation: Mathematical Amplifier.
This demo uses a baseband-equivalent multitone signal as input to the
Amplifier block. A Simulink Slider Gain block enables you to vary the
gain from 1 to 10. The following figure shows the input signal with
gain set to the default 1.
5-5
Amplifier
The next figure shows the same signal after it passes through the
Amplifier block, with the Method parameter set to Hyperbolic
tangent. The demo uses the default Amplifier block IIP3 (dBm) value
of 30. It uses no AM/PM conversion. The demo specifies thermal noise
as Noise figure, for which it uses the default 3.01 dB.
5-6
Amplifier
Parameters for Nonlinear Methods
The following sections discuss parameters specific to the following
models:
• “Cubic Polynomial Model” on page 5-7
• “Hyperbolic Tangent Model” on page 5-8
• “Saleh Model” on page 5-8
• “Ghorbani Model” on page 5-9
• “Rapp Model” on page 5-10
Note The Amplifier block also enables you to model a linear amplifier.
Cubic Polynomial Model
The third-order input intercept point IIP3 (dBm) parameter is used
to compute a scaling factor, which is then applied to the input signal.
The scaling factor is equal to 3 divided by the IIP3 parameter value,
converted from decibels to linear units.
The scaled input is then limited to a maximum value of 1 and the
amplitude gain is applied according to the following function
FAM / AM (u) = u −
u
3
where u is the magnitude of the scaled signal.
The AM/PM conversion (degrees per dB) parameter specifies the
linear phase change. This is applied within the power limits specified
by the Lower input power limit for AM/PM conversion
(dBm) parameter and the Upper input power limit for
AM/PM conversion (dBm) parameter. Outside those limits,
the phase change is constant at the values corresponding to
the lower and upper input power limits, which are zero and
5-7
Amplifier
(AM/PM conversion) ⋅ (upper input power limit − lower input power limit)
,
respectively.
The Linear gain (dB) parameter scales the output signal.
Hyperbolic Tangent Model
The third-order input intercept point IIP3 (dBm) parameter is used
to compute a scaling factor, which is then applied to the input signal.
The scaling factor is equal to 3 divided by the IIP3 parameter value,
converted from decibels to linear units.
The amplitude gain is then applied to the scaled input according to
the following function
where u is the magnitude of the scaled signal.
The AM/PM conversion (degrees per dB) parameter specifies the
linear phase change. This is applied within the power limits specified
by the Lower input power limit for AM/PM conversion
(dBm) parameter and the Upper input power limit for
AM/PM conversion (dBm) parameter. Outside those limits,
the phase change is constant at the values corresponding to
the lower and upper input power limits, which are zero and
(AM/PM conversion) ⋅ (upper input power limit − lower input power limit)
,
respectively.
The Linear gain (dB) parameter scales the output signal.
Saleh Model
The Input scaling (dB) parameter scales the input signal before the
nonlinearity is applied. The block multiplies the input signal by the
parameter value, converted from decibels to linear units. If you set the
parameter to be the inverse of the input signal amplitude, the scaled
signal has amplitude normalized to 1.
The AM/AM parameters, alpha and beta, are used to compute the
amplitude gain for an input signal using the following function
5-8
Amplifier
where u is the magnitude of the scaled signal.
The AM/PM parameters, alpha and beta, are used to compute the phase
change for an input signal using the following function
where u is the magnitude of the input signal. Note that the AM/AM
and AM/PM parameters, although similarly named alpha and beta,
are distinct.
The Output scaling (dB) parameter scales the output signal similarly.
Ghorbani Model
The Input scaling (dB) parameter scales the input signal before the
nonlinearity is applied. The block multiplies the input signal by the
parameter value, converted from decibels to linear units. If you set the
parameter to be the inverse of the input signal amplitude, the scaled
signal has amplitude normalized to 1.
The AM/AM parameters, [x1 x2 x3 x4], are used to compute the amplitude
gain for an input signal using the following function
where u is the magnitude of the scaled signal.
The AM/PM parameters, [y1 y2 y3 y4], are used to compute the phase
change for an input signal using the following function
5-9
Amplifier
where u is the magnitude of the scaled signal.
The Output scaling (dB) parameter scales the output signal similarly.
Rapp Model
The Smoothness factor and Output saturation level parameters
are used to compute the amplitude gain for an input signal by the
following function
where u is the magnitude of the scaled signal, S is the Smoothness
factor and Osat is the Output saturation level.
The Rapp model does not apply a phase change to the input signal.
The Output saturation level parameter limits the output signal
level. The Smoothness factor parameter controls the transition for
the amplitude gain as the input amplitude approaches saturation. The
smaller the smoothness factor, the smoother the curve.
Thermal Noise Simulation
You can specify the amount of thermal noise in three ways, according to
the Specification method parameter you select.
• Noise temperature — Specifies the noise in kelvin.
• Noise factor — Specifies the noise by the following equation:
Noise factor = 1 +
Noise temperature
290
• Noise figure — Specifies the noise in decibels relative to a noise
temperature of 290 kelvin. In terms of noise factor,
Noise figure = 10log(Noise factor)
5-10
Amplifier
Note Some RF blocks require the sample time to perform baseband
modeling calculations. To ensure the accuracy of these calculations,
the Input Port block, as well as the mathematical RF blocks, compare
the input sample time to the sample time you provide in the mask. If
they do not match, or if the input sample time is missing because the
blocks are not connected, an error message appears.
Dialog
Box
The parameters displayed in the dialog box vary for different methods
of modeling nonlinearity. Only some of these parameters are visible
in the dialog box at any one time.
5-11
Amplifier
You can change tunable parameters while the model is running.
Method
Method used to model the nonlinearity. The choices are Linear,
Cubic polynomial, Hyperbolic tangent, Saleh model,
Ghorbani model, Rapp model. Tunable.
Linear gain (dB)
Scalar specifying the linear gain for the output function. This
field becomes visible if you select Linear, Cubic polynomial,
Hyperbolic tangent, or Rapp model as the Method parameter.
Tunable.
IIP3 (dBm)
Input power intercept point as a scalar value. This field becomes
visible if you select Cubic polynomial or Hyperbolic tangent as
the Method parameter. For both of these methods, the nominal
impedance is 1 ohm. Tunable.
AM/PM conversion (degrees per dB)
Scalar specifying the AM/PM conversion in degrees per decibel.
This field becomes visible if you select Cubic polynomial or
Hyperbolic tangent as the Method parameter. Tunable.
Lower input power limit for AM/PM conversion (dBm)
Scalar specifying the minimum input power for which AM/PM
conversion scales linearly with input power value. Below this
value, the phase shift resulting from AM/PM conversion is zero.
This field becomes visible if you select Cubic polynomial or
Hyperbolic tangent as the Method parameter. Tunable.
Upper input power limit for AM/PM conversion (dBm)
Scalar specifying the maximum input power for which AM/PM
conversion scales linearly with input power value. Above this
value, the phase shift resulting from AM/PM conversion is
constant. The value of this maximum shift is given by:
(AM/PM conversion) ⋅ (upper input power limit − lower input power limit)
5-12
Amplifier
This field becomes visible if you select Cubic polynomial or
Hyperbolic tangent as the Method parameter. Tunable.
Input scaling (dB)
Number that scales the input signal level. This field becomes
visible if you select Saleh model or Ghorbani model as the
Method parameter. Tunable.
Output scaling (dB)
Number that scales the output signal level. This field becomes
visible if you select Saleh model or Ghorbani model as the
Method parameter. Tunable.
AM/AM parameters [alpha beta]
Vector specifying the AM/AM parameters. This field becomes
visible if you select Saleh model as the Method parameter.
Tunable.
AM/PM parameters [alpha beta]
Vector specifying the AM/PM parameters. This field becomes
visible if you select Saleh model as the Method parameter.
Tunable.
AM/AM parameters [x1 x2 x3 x4]
Vector specifying the AM/AM parameters. This field becomes
visible if you select Ghorbani model as the Method parameter.
Tunable.
AM/PM parameters [y1 y2 y3 y4]
Vector specifying the AM/PM parameters. This field becomes
visible if you select Ghorbani model as the Method parameter.
Tunable.
Smoothness factor
Scalar specifying the smoothness factor. This field becomes visible
if you select Rapp model as the Method parameter. Tunable.
Output saturation level
Scalar specifying the output saturation level. This field becomes
visible if you select Rapp model as the Method parameter.
Tunable.
5-13
Amplifier
Specification method
The method by which you specify the amount of noise. The choices
are Noise temperature, Noise figure, and Noise factor.
Tunable.
Noise temperature (K)
Scalar specifying the amount of noise. This field becomes visible
if you select Noise temperature as the Specification method
parameter. Tunable.
Noise figure (dB)
Scalar specifying the amount of noise relative to a noise
temperature of 290 kelvin. A Noise figure setting of 0 dB
indicates a noiseless system. This field becomes visible if you
select Noise figure as the Specification method parameter.
Tunable.
Noise factor
Scalar specifying the amount of noise relative to a noise
temperature of 290 kelvin. This field becomes visible if you
select Noise factor as the Specification method parameter.
Tunable.
Initial seed
Nonnegative integer specifying the initial seed for the random
number generator the block uses to generate noise.
References
[1] Ghorbani, A. and M. Sheikhan, “The Effect of Solid State Power
Amplifiers (SSPAs) Nonlinearities on MPSK and M-QAM Signal
Transmission,” Sixth Int’l Conference on Digital Processing of Signals in
Comm., 1991, pp. 193-197.
[2] Rapp, C., “Effects of HPA-Nonlinearity on a 4-DPSK/OFDM-Signal
for a Digital Sound Broadcasting System,” in Proceedings of the Second
European Conference on Satellite Communications, Liege, Belgium, Oct.
22-24, 1991, pp. 179-184.
5-14
Amplifier
[3] Saleh, A.A.M., “Frequency-independent and frequency-dependent
nonlinear models of TWT amplifiers,” IEEE Trans. Communications,
vol. COM-29, pp.1715-1720, November 1981.
See Also
Bandpass RF Filter, Bandstop RF Filter, Highpass RF Filter, Lowpass
RF Filter, Mixer
5-15
Bandpass RF Filter
Purpose
Standard bandpass RF filters in baseband-equivalent complex form
Library
Mathematical
Description
The Bandpass RF Filter block lets you design standard analog bandpass
filters, implemented in baseband-equivalent complex form. The
following table describes the available design methods.
Design Method
Description
Butterworth
The magnitude response of a Butterworth
filter is maximally flat in the passband and
monotonic overall.
Chebyshev I
The magnitude response of a Chebyshev I filter
is equiripple in the passband and monotonic
in the stopband.
Chebyshev II
The magnitude response of a Chebyshev II
filter is monotonic in the passband and
equiripple in the stopband.
Elliptic
The magnitude response of an elliptic filter
is equiripple in both the passband and the
stopband.
Bessel
The delay of a Bessel filter is maximally flat
in the passband.
The block input must be a discrete-time complex signal.
Note This block assumes a nominal impedance of 1 ohm.
Select the design of the filter from the Design method list in the dialog
box. For each design method, the block enables you to specify the filter
design parameters shown in the following table.
5-16
Bandpass RF Filter
Design Method
Filter Design Parameters
Butterworth
Order, lower passband edge frequency, upper
passband edge frequency
Chebyshev I
Order, lower passband edge frequency, upper
passband edge frequency, passband ripple
Chebyshev II
Order, lower stopband edge frequency, upper
stopband edge frequency, stopband attenuation
Elliptic
Order, lower passband edge frequency, upper
passband edge frequency, passband ripple,
stopband attenuation
Bessel
Order, lower passband edge frequency, upper
passband edge frequency
The Bandpass RF Filter block designs the filters using the Signal
Processing Toolbox filter design functions buttap, cheb1ap, cheb2ap,
ellipap, and besselap.
Note Some RF blocks require the sample time to perform baseband
modeling calculations. To ensure the accuracy of these calculations, the
Input Port block, as well as the mathematical RF blocks, compare the
input sample time to the sample time you provide in the mask. If they
do not match, or if the input sample time is missing because the blocks
are not connected, an error message appears.
5-17
Bandpass RF Filter
Dialog
Box
The parameters displayed in the dialog box vary for different design
methods. Only some of these parameters are visible in the dialog box
at any one time.
You can change tunable parameters while the model is running.
Design method
Filter design method. The design method can be Butterworth,
Chebyshev I, Chebyshev II, Elliptic, or Bessel. Tunable.
Filter order
Order of the lowpass analog prototype filter that forms the basis
for the bandpass filter design. The order of the final filter is twice
this value.
5-18
Bandpass RF Filter
Lower passband edge frequency (Hz)
Lower passband edge frequency for Butterworth, Chebyshev I,
elliptic, and Bessel designs. Tunable.
Upper passband edge frequency (Hz)
Upper passband edge frequency for Butterworth, Chebyshev I,
elliptic, and Bessel designs. Tunable.
Lower stopband edge frequency (Hz)
Lower stopband edge frequency for Chebyshev II designs.
Tunable.
Upper stopband edge frequency (Hz)
Upper stopband edge frequency for Chebyshev II designs.
Tunable.
Passband ripple in dB
Passband ripple for Chebyshev I and elliptic designs. Tunable.
Stopband attenuation in dB
Stopband attenuation for Chebyshev II and elliptic designs.
Tunable.
Finite impulse response filter length
Desired length of the baseband-equivalent impulse response for
the filter.
Center frequency (Hz)
Center of the modeling frequencies.
Sample time (s)
Time interval between consecutive samples of the input signal.
See Also
Amplifier, Bandstop RF Filter, Highpass RF Filter, Lowpass RF Filter,
Mixer
buttap, cheb1ap, cheb2ap, ellipap, besselap (Signal Processing
Toolbox)
5-19
Bandstop RF Filter
Purpose
Standard bandstop RF filters in baseband-equivalent complex form
Library
Mathematical
Description
The Bandstop RF Filter block lets you design standard analog bandstop
filters, implemented in baseband-equivalent complex form. The
following table describes the available design methods.
Design Method
Description
Butterworth
The magnitude response of a Butterworth
filter is maximally flat in the passband
and monotonic overall.
Chebyshev I
The magnitude response of a Chebyshev I
filter is equiripple in the passband and
monotonic in the stopband.
Chebyshev II
The magnitude response of a Chebyshev II
filter is monotonic in the passband and
equiripple in the stopband.
Elliptic
The magnitude response of an elliptic
filter is equiripple in both the passband
and the stopband.
Bessel
The delay of a Bessel filter is maximally
flat in the passband.
The block input must be a discrete-time complex signal.
Note This block assumes a nominal impedance of 1 ohm.
5-20
Bandstop RF Filter
Select the design of the filter from the Design method list in the dialog
box. For each design method, the block enables you to specify the filter
design parameters shown in the following table.
Design Method
Filter Design Parameters
Butterworth
Order, lower passband edge frequency,
upper passband edge frequency
Chebyshev I
Order, lower passband edge frequency,
upper passband edge frequency, passband
ripple
Chebyshev II
Order, lower stopband edge frequency,
upper stopband edge frequency, stopband
attenuation
Elliptic
Order, lower passband edge frequency,
upper passband edge frequency, passband
ripple, stopband attenuation
Bessel
Order, lower passband edge frequency,
upper passband edge frequency
The Bandstop RF Filter block designs the filters using the Signal
Processing Toolbox filter design functions buttap, cheb1ap, cheb2ap,
ellipap, and besselap.
Note Some RF blocks require the sample time to perform baseband
modeling calculations. To ensure the accuracy of these calculations, the
Input Port block, as well as the mathematical RF blocks, compare the
input sample time to the sample time you provide in the mask. If they
do not match, or if the input sample time is missing because the blocks
are not connected, an error message appears.
5-21
Bandstop RF Filter
Dialog
Box
The parameters displayed in the dialog box vary for different design
methods. Only some of these parameters are visible in the dialog box
at any one time.
You can change tunable parameters while the model is running.
Design method
Filter design method. The design method can be Butterworth,
Chebyshev I, Chebyshev II, Elliptic, or Bessel. Tunable.
Filter order
Order of the lowpass analog prototype filter that forms the basis
for the bandstop filter design. The order of the final filter is twice
this value.
Lower passband edge frequency (Hz)
Lower passband edge frequency for Butterworth, Chebyshev I,
elliptic, and Bessel designs. Tunable.
5-22
Bandstop RF Filter
Upper passband edge frequency (Hz)
Upper passband edge frequency for Butterworth, Chebyshev I,
elliptic, and Bessel designs. Tunable.
Lower stopband edge frequency (Hz)
Lower stopband edge frequency for Chebyshev II designs.
Tunable.
Upper stopband edge frequency (Hz)
Upper stopband edge frequency for Chebyshev II designs.
Tunable.
Passband ripple in dB
Passband ripple for Chebyshev I and elliptic designs. Tunable.
Stopband attenuation in dB
Stopband attenuation for Chebyshev II and elliptic designs.
Tunable.
Finite impulse response filter length
Desired length of the baseband-equivalent impulse response for
the filter.
Center frequency (Hz)
Center of the modeling frequencies.
Sample time (s)
Time interval between consecutive samples of the input signal.
See Also
Amplifier, Bandpass RF Filter, Highpass RF Filter, Lowpass RF Filter,
Mixer
buttap, cheb1ap, cheb2ap, ellipap, besselap (Signal Processing
Toolbox)
5-23
Coaxial Transmission Line
Purpose
Model coaxial transmission line
Library
Transmission Lines sublibrary of the Physical library
Description
The Coaxial Transmission Line block models the coaxial transmission
line described in the block dialog box in terms of its frequency-dependent
S-parameters. A coplanar waveguide transmission line is shown here in
cross-section. Its physical characteristics include the radius of the inner
conductor a and the radius of the outer conductor b.
The block lets you model the transmission line as a stub or as a stubless
line.
Stubless Transmission Line
If you model a coaxial transmission line as a stubless line, the
Coaxial Transmission Line block calculates the frequency-dependent
S-parameters using the physical length of the transmission line, D, and
the complex propagation constant, k.
5-24
Coaxial Transmission Line
k is a vector whose elements correspond to the elements of f, a vector of
modeling frequencies. It can be expressed in terms of the resistance (R),
inductance (L), conductance (G), and capacitance (C) per unit length
(meters) as
where
In these equations,
is the conductivity in the conductor and
is
the conductivity in the dielectric. is the permeability of the dielectric,
is its permittivity, and skin depth is calculated as
. f is a
vector of modeling frequencies determined by the Output Port block.
The Coaxial Transmission Line block normalizes the resulting
S-parameters to a reference impedance of 50 ohms.
Shunt and Series Stubs
If you model the transmission line as a shunt or series stub, the Coaxial
Transmission Line block first calculates the ABCD-parameters at each
frequency contained in the modeling frequencies vector. It then uses the
abcd2s function to convert the ABCD-parameters to S-parameters.
Shunt ABCD-Parameters
When you set the Stub mode parameter in the mask dialog box to
Shunt, the two-port network consists of a stub transmission line that
you can terminate with either a short circuit or an open circuit as
shown here.
5-25
Coaxial Transmission Line
Zin is the input impedance of the shunt circuit. The ABCD-parameters
for the shunt stub are calculated as
Series ABCD-Parameters
When you set the Stub mode parameter in the mask dialog box to
Series, the two-port network consists of a series transmission line
that you can terminate with either a short circuit or an open circuit
as shown here.
Zin is the input impedance of the series circuit. The ABCD-parameters
for the series stub are calculated as
5-26
Coaxial Transmission Line
Dialog
Box
Outer radius (m)
Radius of the outer conductor of the coaxial transmission line.
5-27
Coaxial Transmission Line
Inner radius (m)
Radius of the inner conductor of the coaxial transmission line.
Relative permeability constant
Relative permeability of the dielectric expressed as the ratio of the
permeability of the dielectric to permeability in free space .
Relative permittivity constant
Relative permittivity of the dielectric expressed as the ratio of the
permittivity of the dielectric to permittivity in free space .
Conductivity in conductor (S/m)
Conductivity of the conductor in siemens per meter.
Conductivity in dielectric (S/m)
Conductivity of the dielectric in siemens per meter.
Transmission line length (m)
Physical length of the transmission line.
Stub mode
Type of stub. Choices are Not a stub, Shunt, or Series.
Termination of stub
Stub termination for stub modes Shunt and Series. Choices are
Open or Short. This parameter becomes visible only when Stub
mode is set to Shunt or Series.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
5-28
References
[1] Ludwig, Reinhold and Pavel Bretchko, RF Circuit Design: Theory
and Applications, Prentice-Hall, 2000.
See Also
Coplanar Waveguide Transmission Line, General Passive Network,
Transmission Line, Microstrip Transmission Line, Parallel-Plate
Transmission Line, Two-Wire Transmission Line
Coplanar Waveguide Transmission Line
Purpose
Model coplanar waveguide transmission line
Library
Transmission Lines sublibrary of the Physical library
Description
The Coplanar Waveguide Transmission Line block models the
coplanar waveguide transmission line described in the block dialog
box in terms of its frequency-dependent S-parameters. A coplanar
waveguide transmission line is shown here in cross-section. Its
physical characteristics include the conductor width (w), the conductor
thickness (t), the slot width (s), the substrate height (d), and the relative
permittivity constant ( ).
The block lets you model the transmission line as a stub or as a stubless
line.
Stubless Transmission Line
If you model a coplanar waveguide transmission line as a stubless
line, the Coplanar Waveguide Transmission Line block calculates the
frequency-dependent S-parameters using the physical length of the
transmission line, D, and the complex propagation constant, k.
, where
is the attenuation coefficient and is the wave
number. The attenuation coefficient
is related to the loss, , by
5-29
Coplanar Waveguide Transmission Line
where is the reduction in signal strength, in dB, per unit length.
combines both conductor loss and dielectric loss and is derived from the
physical parameters specified in the Coplanar Waveguide Transmission
Line block dialog box.
The wave number
is related to the phase velocity, VP, by
, where
is the frequency-dependent effective dielectric
constant. f is a vector of modeling frequencies determined by the
Output Port block. The phase velocity VP is also known as the wave
propagation velocity.
The Coplanar Waveguide Transmission Line block normalizes the
resulting S-parameters to a reference impedance of 50 ohms.
Shunt and Series Stubs
If you model the transmission line as a shunt or series stub, the
Coplanar Waveguide Transmission Line block first calculates the
ABCD-parameters at each frequency contained in the vector of
modeling frequencies. It then uses the abcd2s function to convert the
ABCD-parameters to S-parameters.
Shunt ABCD-Parameters
When you set the Stub mode parameter in the mask dialog box to
Shunt, the two-port network consists of a stub transmission line that
you can terminate with either a short circuit or an open circuit as
shown here.
5-30
Coplanar Waveguide Transmission Line
Zin is the input impedance of the shunt circuit. The ABCD-parameters
for the shunt stub are calculated as
Series ABCD-Parameters
When you set the Stub mode parameter in the mask dialog box to
Series, the two-port network consists of a series transmission line
that you can terminate with either a short circuit or an open circuit
as shown here.
Zin is the input impedance of the series circuit. The ABCD-parameters
for the series stub are calculated as
5-31
Coplanar Waveguide Transmission Line
Dialog
Box
5-32
Coplanar Waveguide Transmission Line
Conductor width (m)
Physical width of the conductor.
Slot width (m)
Physical width of the slot.
Substrate height (m)
Thickness of the dielectric on which the conductor resides.
Strip thickness (m)
Physical thickness of the conductor.
Relative permittivity constant
Relative permittivity of the dielectric expressed as the ratio of the
permittivity of the dielectric to permittivity in free space .
Conductivity in conductor (S/m)
Conductivity of the conductor in siemens per meter.
Loss tangent in dielectric
Loss angle tangent of the dielectric.
Transmission line length (m)
Physical length of the transmission line.
Stub mode
Type of stub. Choices are Not a stub, Shunt, or Series.
Termination of stub
Stub termination for stub modes Shunt and Series. Choices are
Open or Short. This parameter becomes visible only when Stub
mode is set to Shunt or Series.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
References
[1] Gupta, K. C., Ramesh Garg, Inder Bahl, and Prakash Bhartia,
Microstrip Lines and Slotlines, 2nd Edition, Artech House, Inc.,
Norwood, MA, 1996.
5-33
Coplanar Waveguide Transmission Line
See Also
5-34
Coaxial Transmission Line, General Passive Network, Transmission
Line, Microstrip Transmission Line, Parallel-Plate Transmission Line,
Two-Wire Transmission Line
General Amplifier
Purpose
Model nonlinear amplifier described by rfdata object
Library
Amplifiers sublibrary of the Physical library
Description
The General Amplifier block models the nonlinear amplifier described
by an RF Toolbox data (rfdata.data) object.
Network Parameters
If network parameter data and their corresponding frequencies exist as
S-parameters in the rfdata.data object, the General Amplifier block
interpolates the S-parameters to determine their values at the modeling
frequencies. If the block contains network Y- or Z-parameters, the block
first converts them to S-parameters. See Appendix A, “RF Blockset
Algorithms” for more details.
Nonlinearity
If power data exists in the rfdata.data object, the block extracts the
AMAM/AMPM nonlinearities from the power data.
If the rfdata.data object contains no power data, then you can enter
either the OIP3 or IIP3 as a scalar value for nonlinearity in the General
Amplifier block dialog box.
Active Noise
If active spot noise data exists in the rfdata.data object, the block
uses the data to calculate the noise figure. The block first interpolates
the noise data for the modeling frequencies, using the specified
Interpolation method. It then calculates the noise figure using the
resulting values.
If the rfdata.data object contains no noise data, then you can enter a
value for the noise figure in the General Amplifier block dialog box.
Data Consistency
If you create the rfdata.data object by reading data from a MathWorks
AMP file that contains both network parameter data and power data,
the RF Blockset checks the data for consistency and reconciles it as
necessary.
5-35
General Amplifier
The RF Blockset compares the small-signal amplifier gain defined
by the network parameters, S21, and by the power data, Pout-Pin. The
discrepancy between the two is computed in dBm using the following
equation:
ΔP = S21 ( f P ) − Pout ( f P ) + Pin ( f P ) (dBm)
where fP is the lowest frequency for which power data is specified.
P is more than 0.4 dB, a warning appears and the RF Blockset adds
P to the output power values at each specified input power value to
resolve the discrepancy for simulation. This discrepancy is shown in
the following graph.
If
Small Signal Network Data
*** Specified Power Data
xxx Reconciled Power Data
x
x
x
*
*
*
x
Pout (dBm)
x
*
DP *
*
fP
5-36
x
Pin (dBm)
General Amplifier
Dialog
Box
RFDATA object
An RF Toolbox data (rfdata.data) object. You can specify the
object as (1) the handle of a data object previously created using
the RF Toolbox, (2) an RF Toolbox command such as rfdata.data,
which creates a default data object, or (3) a MATLAB expression
that generates such an object. See the RF Toolbox documentation
for more information about data objects.
Interpolation method
For network data, the method used to interpolate the parameters
contained in the rfdata.data object. Interpolation can be Cubic,
Linear (default), or Spline.
IP3 type
Type of third-order intercept point. The value can be IIP3 (input
intercept point) or OIP3 (output intercept point). This parameter
becomes visible only if the rfdata.data object contains no power
data.
5-37
General Amplifier
IIP3 (dBm)
Input power intercept point as a scalar value. This field becomes
visible if you select IIP3 as the IP3 type. This parameter becomes
visible only if the rfdata.data object contains no power data.
OIP3 (dBm)
Output power intercept point as a scalar value. This field becomes
visible if you select OIP3 as the IP3 type. This parameter becomes
visible only if the rfdata.data object contains no power data.
Noise figure (dB)
Scalar ratio of the available signal-to-noise power ratio at the
input to the available signal-to-noise power ratio at the output,
(Si/Ni)/(So/No). This parameter becomes visible only if the
rfdata.data object contains no noise data.
Note For information about plotting the amplifier parameters, see
Chapter 3, “Plotting Model Data”. Use rftool or the RF Toolbox
plotting functions to plot other data.
Examples
Creating a General Amplifier Block from File Data
This example uses the RF Toolbox read function to create an
rfdata.data object that describes the nonlinear amplifier in the
file default.amp. The file, which is read into an RF Toolbox data
(rfdata.data) object, contains S-parameters for frequencies from 1.0
to 2.9 GHz at intervals of 0.01 GHz, power data at frequency 2.1 GHz,
and active noise parameters. The General Amplifier block uses linear
interpolation to model the network described in the object.
Note See “AMP File Format” in the RF Toolbox documentation for
information about .amp files.
5-38
General Amplifier
The plot parameters in the dialog box request a Z Smith chart of the
S22 parameters using the frequencies taken from the RFDATA object
parameter.
5-39
General Amplifier
See Also
Output Port, S-Parameters Amplifier, Y-Parameters Amplifier,
Z-Parameters Amplifier
rfdata, rfdata.data (RF Toolbox)
interp1 (MATLAB)
5-40
General Circuit Element
Purpose
Model two-port network described by rfckt object
Library
Black Box Elements sublibrary of the Physical library
Description
The General Circuit Element block models the two-port network
described by an RF Toolbox circuit (rfckt) object.
The block uses the rfckt/analyze method to calculate the network
parameters at the modeling frequencies.
Dialog
Box
RFCKT object
An RF Toolbox circuit (rfckt) object. You can specify the object
as (1) the handle of a circuit object previously created using the
RF Toolbox, (2) an RF Toolbox command such as rfckt.txline,
rfckt.coaxial, or rfckt.cascade that creates a default circuit
object of the specified type, or (3) a MATLAB expression that
generates such an object. See the RF Toolbox documentation for
more information about circuit objects.
5-41
General Circuit Element
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
Examples
Creating a General Circuit Element from an RF Toolbox Object
This example uses the rfckt.txline object, which describes a
transmission line.
The plot parameters in the dialog box request an X-Y plane plot of the
S12 parameters in the frequency range 1.9 to 2.2 GHz.
5-42
General Circuit Element
See Also
General Passive Network, S-Parameters Passive Network, Y-Parameters
Passive Network, Z-Parameters Passive Network
rfckt (RF Toolbox)
interp1 (MATLAB)
5-43
General Mixer
Purpose
Model mixer described by rfdata object
Library
Mixer sublibrary of the Physical library
Description
The General Mixer block models the mixer described by an RF Toolbox
data (rfdata.data) object.
Network Parameters
The network parameter values all refer to the mixer input frequency.
If network parameter data and their corresponding frequencies exist
as S-parameters in the rfdata.data object, the General Mixer block
interpolates the S-parameters to determine their values at the modeling
frequencies. If the block contains network Y- or Z-parameters, the
block first converts them to S-parameters. See “Mapping Network
Parameters to Modeling Frequencies” on page A-5 for more details.
The RF Blockset computes the normalized reflected amplitude at the
mixer input ( Er1 ) and at the mixer output ( Er2 ) from the interpolated
S-parameters as
Er1 ( fin ) = S11 ( fin ) Ei1 ( fin ) + S12 ( fin ) Ei2 ( fout )
Er 2 ( fout ) = S21 ( fin ) Ei1 ( fin ) + S22 ( fin ) Ei2 ( fout )
where
•
fin and f out are the mixer input and output frequencies, respectively.
• Ei1 and Ei2 are the normalized incident amplitudes at the mixer
input and output, respectively.
The interpolated S21 parameter values describe the conversion gain as
a function of frequency, referred to the mixer input frequency.
Active Noise
If active spot noise data exists in the rfdata.data object, the block uses
the data to calculate the noise figure. It first interpolates the noise
5-44
General Mixer
data for the modeling frequencies, using the specified Interpolation
method. It then calculates the noise figure using the resulting values.
If the rfdata.data object contains no noise data, the General Mixer
block dialog lets you enter a value for the noise figure.
Phase Noise
The General Mixer block applies phase noise to a complex baseband
signal. The block first applies generates additive white Gaussian noise
(AWGN) and filters it with a digital filter. It then adds the resulting
noise to the angle component of the input signal.
5-45
General Mixer
Dialog
Box
RFDATA object
An RF Toolbox data object (rfdata.data) that describes a mixer.
You can specify the object as (1) the handle of a data object
previously created using the RF Toolbox, (2) an RF Toolbox
command such as rfdata.data that creates a default data object,
or (3) a MATLAB expression that generates such an object. See
the RF Toolbox documentation for more information about data
objects.
5-46
General Mixer
Interpolation method
For network data, the method used to interpolate the parameters
contained in the rfdata.data object. Interpolation can be Cubic,
Linear (default), or Spline.
Type
Type of mixer. Choices are Downconverter (default) and
Upconverter.
LO frequency (Hz)
Local oscillator frequency. If you choose Downconverter, the RF
Blockset computes the mixer output frequency,
f out , from the
mixer input frequency, f in , and the local oscillator frequency, f lo ,
.
. If you choose Upconverter,
as
Note The mixer output frequency must be positive. This means
that if you choose a downconverting mixer,
than
fin must be greater
flo . Otherwise, an error appears.
IP3 type
Type of third-order intercept point. The value can be IIP3 (input
intercept point) or OIP3 (output intercept point). This parameter
becomes visible only if the rfdata.data object contains no power
data.
IIP3 (dBm)
Input power intercept point as a scalar value. This field becomes
visible if you select IIP3 as the IP3 type. This parameter becomes
visible if the rfdata.data object contains no power data and you
select IIP3 as the IP3 type.
OIP3 (dBm)
Output power intercept point as a scalar value. This field becomes
visible if you select OIP3 as the IP3 type. This parameter becomes
5-47
General Mixer
visible if the rfdata.data object contains no power data and you
select OIP3 as the IP3 type.
Noise figure (dB)
Scalar ratio of the available signal-to-noise power ratio at the
input to the available signal-to-noise power ratio at the output,
(Si/Ni)/(So/No). This parameter becomes visible only if the
rfdata.data object contains no noise data.
Phase noise frequency offset (Hz)
Vector specifying the frequency offset.
Phase noise level (dBc/Hz)
Vector specifying the phase noise level.
Note For information about plotting the mixer parameters, see
Chapter 3, “Plotting Model Data”. Use RF Tool or the RF Toolbox
plotting functions to plot other data.
See Also
Output Port, S-Parameters Mixer, Y-Parameters Mixer, Z-Parameters
Mixer
rfdata, rfdata.data (RF Toolbox)
5-48
General Passive Network
Purpose
Model two-port passive network described by rfdata object
Library
Black Box Elements sublibrary of the Physical library
Description
The General Passive Network block models the two-port passive
network described by an RF Toolbox data (rfdata.data) object.
If network parameter data and their corresponding frequencies exist as
S-parameters in the rfdata.data object, the General Passive Network
block interpolates the S-parameters to determine their values at the
modeling frequencies. If the block contains network Y- or Z-parameters,
the block first converts them to S-parameters. See “Mapping Network
Parameters to Modeling Frequencies” on page A-5 for more details.
Dialog
Box
RFDATA object
An RF Toolbox data (rfdata.data) object. You can specify the
object as (1) the handle of a data object previously created using
the RF Toolbox, (2) an RF Toolbox command such as rfdata.data
that creates a default data object, or (3) a MATLAB expression
5-49
General Passive Network
that generates such an object. See the RF Toolbox documentation
for more information about data objects.
Interpolation method
Method used to interpolate the parameters contained in the
rfdata object. Interpolation can be Linear (default), Spline, or
Cubic.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
Examples
Creating a General Passive Network Block from File Data
This example uses the RF Toolbox read function to create an
rfdata.data object that describes the two-port passive network in the
file passive.s2p. The file contains S-parameters for frequencies from
about 0.315 MHz to 6.0 GHz. The General Passive Network block uses
linear interpolation to model the network described in the object.
5-50
General Passive Network
The plot parameters in the dialog box request a Z Smith chart of the
S11 parameters using the frequencies taken from the RFDATA object
parameter.
See Also
General Circuit Element, Output Port, S-Parameters Passive Network,
Y-Parameters Passive Network, Z-Parameters Passive Network
rfdata, rfdata.data (RF Toolbox)
interp1 (MATLAB)
5-51
Highpass RF Filter
Purpose
Standard highpass RF filters in baseband-equivalent complex form
Library
Mathematical
Description
The Highpass RF Filter block lets you design standard analog highpass
filters, implemented in baseband-equivalent complex form. The
following table describes the available design methods.
Design Method
Description
Butterworth
The magnitude response of a Butterworth
filter is maximally flat in the passband and
monotonic overall.
Chebyshev I
The magnitude response of a Chebyshev I
filter is equiripple in the passband and
monotonic in the stopband.
Chebyshev II
The magnitude response of a Chebyshev II
filter is monotonic in the passband and
equiripple in the stopband.
Elliptic
The magnitude response of an elliptic filter
is equiripple in both the passband and the
stopband.
Bessel
The delay of a Bessel filter is maximally flat
in the passband.
The block input must be a discrete-time complex signal.
Note This block assumes a nominal impedance of 1 ohm.
Select the design of the filter from the Design method list in the dialog
box. For each design method, the block lets you specify the filter design
parameters shown in the following table.
5-52
Highpass RF Filter
Design Method
Filter Design Parameters
Butterworth
Order, passband edge frequency
Chebyshev I
Order, passband edge frequency, passband
ripple
Chebyshev II
Order, stopband edge frequency, stopband
attenuation
Elliptic
Order, passband edge frequency, passband
ripple, stopband attenuation
Bessel
Order, passband edge frequency
The Highpass RF Filter block designs the filters using the Signal
Processing Toolbox filter design functions buttap, cheb1ap, cheb2ap,
ellipap, and besselap.
Note Some RF blocks require the sample time to perform baseband
modeling calculations. To ensure the accuracy of these calculations, the
Input Port block, as well as the mathematical RF blocks, compare the
input sample time to the sample time you provide in the mask. If they
do not match, or if the input sample time is missing because the blocks
are not connected, an error message appears.
5-53
Highpass RF Filter
Dialog
Box
The parameters displayed in the dialog box vary for different design
methods. Only some of these parameters are visible in the dialog box
at any one time.
You can change tunable parameters while the model is running.
Design method
Filter design method. The design method can be Butterworth,
Chebyshev I, Chebyshev II, Elliptic, or Bessel. Tunable.
Filter order
Order of the filter.
Passband edge frequency (Hz)
Passband edge frequency for Butterworth, Chebyshev I, elliptic,
and Bessel designs. Tunable.
Stopband edge frequency (Hz)
Stopband edge frequency for Chebyshev II designs. Tunable.
5-54
Highpass RF Filter
Passband ripple in dB
Passband ripple for Chebyshev I and elliptic designs. Tunable.
Stopband attenuation in dB
Stopband attenuation for Chebyshev II and elliptic designs.
Tunable.
Finite impulse response filter length
Desired length of the baseband-equivalent impulse response for
the filter.
Center frequency (Hz)
Center of the modeling frequencies.
Sample time
Time interval between consecutive samples of the input signal.
See Also
Amplifier, Bandpass RF Filter, Bandstop RF Filter, Lowpass RF Filter,
Mixer
buttap, cheb1ap, cheb2ap, ellipap, besselap (Signal Processing
Toolbox)
5-55
Input Port
Purpose
Connection block from Simulink environment to RF physical blocks
Library
Input/Output Ports sublibrary of the Physical library
Description
The Input Port block serves as a connecting port from the Simulink, or
mathematical, part of the model to an RF physical part of the model.
The Input Port block lets you provide the parameter data needed
to calculate the modeling frequencies and the baseband-equivalent
impulse response for the physical subsystem.
For more information about how the Input Port block converts the
mathematical Simulink signals to RF Blockset physical modeling
environment signals, see “Converting to and from Simulink Signals” on
page A-15. For more information about connecting mathematical and
physical parts of a model, see Chapter 2, “Modeling an RF System”.
Note Some RF blocks require the sample time to perform baseband
modeling calculations. To ensure the accuracy of these calculations, the
Input Port block, as well as the mathematical RF blocks, compare the
input sample time to the sample time you provide in the Input Port
mask. If they do not match, or if the input sample time is missing
because the blocks are not connected, an error message appears.
5-56
Input Port
Dialog
Box
Finite impulse response filter length
Desired length of the baseband-equivalent impulse response for
the physical model. The longer the FIR filter in the time-domain,
the finer the frequency resolution in the frequency domain.
The frequency resolution is approximately equal to 1/ (finite
impulse response filter length*sample time). For a graphical
representation of this parameter, see “Baseband-Equivalent
Modeling” on page A-10.
Center frequency (Hz)
Center of the modeling frequencies. See the Output Port block
reference page for information about calculating the modeling
frequencies.
5-57
Input Port
Sample time (s)
Time interval between consecutive samples of the input signal.
Source impedance
Source impedance of the RF network described in the physical
model to which it connects.
Add noise
If you select this parameter, noise data in the RF physical blocks
that are bracketed by the Input Port block and Output Port block
is taken into consideration. If you do not select this block, noise
data is ignored.
Initial seed
Nonnegative integer specifying the initial seed for the random
number generator the block uses to generate noise. This
parameter becomes visible if you select the Add noise parameter.
See Also
5-58
Output Port
LC Bandpass Pi
Purpose
Model LC bandpass pi network
Library
Ladder Filters sublibrary of the Physical library
Description
The LC Bandpass Pi block models the LC bandpass pi network
described in the block dialog box, in terms of its frequency-dependent
S-parameters.
For each inductor and capacitor pair in the network, the block first
calculates the ABCD-parameters at each frequency contained in the
vector of modeling frequencies. For each series pair, A = 1, B = Z, C = 0,
and D = 1, where Z is the impedance of the series pair. For each shunt
pair, A = 1, B = 0, C = Y, and D = 1, where Y is the admittance of the
shunt pair.
The LC Bandpass Pi block then cascades the ABCD-parameters for
each series and shunt pair at each of the modeling frequencies, and
converts the cascaded parameters to S-parameters using the RF Toolbox
abcd2s function.
See the Output Port block for information about determining the
modeling frequencies.
The LC bandpass pi network object is a two-port network as shown in
the circuit diagram below.
C2
L2
L1
C1
C4
L4
L3
C3
[L1, L2, L3, L4, ...] is the value of the 'L' property, and [C1, C2, C3, C4, ...]
is the value of the 'C' property.
5-59
LC Bandpass Pi
Dialog
Box
Inductance (H)
Vector containing the inductances, in order from source to load, of
all inductors in the network. The inductance vector must contain
at least three elements. All values must be strictly positive.
Capacitance (F)
Vector containing the capacitances, in order from source to load,
of all capacitors in the network. Its length must be equal to the
length of the vector you provide in the Inductance parameter.
All values must be strictly positive.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
5-60
LC Bandpass Pi
Examples
Using a Ladder Filter Block to Filter Gaussian Noise
This example provides complex random noise in Gaussian form as input
to an LC Bandpass Pi block. A Spectrum Scope block (Signal Processing
Blockset) plots the filtered output.
The Random Source block (Signal Processing Blockset) produces
frame-based output at 512 samples per frame. Its Sample time
parameter is set to 1.0e-9. This sample time must match the sample
time for the physical part of the model, which you provide in the Input
Port block diagram.
5-61
LC Bandpass Pi
The Input Port block specifies Finite impulse response filter length
as 256, Center frequency as 700.0e6 Hz, Sample time as 1.0e-9, and
Source impedance as 50 ohms.
The LC Bandpass Pi block provides the inductances for three inductors,
in order from source to load, [1.4446e-9, 4.3949e-8, 1.4446e-9].
Similarly, it provides the capacitances for three capacitors [3.5785e-11,
1.1762e-12, 3.5785e-11].
5-62
LC Bandpass Pi
The following plot shows a sample of the baseband-equivalent RF signal
generated by this LC Bandpass Pi block. Zero (0) on the frequency axis
corresponds to the center frequency specified in the Input Port block.
The bandwidth of the frequency spectrum is 1/sample time. You specify
the Sample time parameter in the Input Port block.
5-63
LC Bandpass Pi
The Axis Properties of the Spectrum Scope block have been adjusted
to show the frequencies above and below the carrier. The Minimum
Y-limit parameter is -90, and Maximum Y-limit is 0.
References
[1] Ludwig, Reinhold and Pavel Bretchko, RF Circuit Design: Theory
and Applications, Prentice-Hall, 2000.
[2] Zverev, Anatol I., Handbook of Filter Synthesis, John Wiley & Sons,
1967.
See Also
5-64
General Passive Network, LC Bandpass Tee, LC Bandstop Pi, LC
Bandstop Tee, LC Highpass Pi, LC Highpass Tee, LC Lowpass Pi, LC
Lowpass Tee, Series RLC, Shunt RLC
LC Bandpass Tee
Purpose
Model LC bandpass tee network
Library
Ladder Filters sublibrary of the Physical library
Description
The LC Bandpass Tee block models the LC bandpass tee network
described in the block dialog box, in terms of its frequency-dependent
S-parameters.
For each inductor and capacitor pair in the network, the block first
calculates the ABCD-parameters at each frequency contained in the
vector of modeling frequencies. For each series pair, A = 1, B = Z, C = 0,
and D = 1, where Z is the impedance of the series pair. For each shunt
pair, A = 1, B = 0, C = Y, and D = 1, where Y is the admittance of the
shunt pair.
The LC Bandpass Tee block then cascades the ABCD-parameters
for each series and shunt pair at each of the modeling frequencies,
and converts the cascaded parameters to S-parameters using the RF
Toolbox abcd2s function.
See the Output Port block reference page for information about
determining the modeling frequencies.
The LC bandpass tee network object is a two-port network as shown in
the circuit diagram below.
L1
C1
L3
L2
C3
C2
L4
C4
[L1, L2, L3, L4, ...] is the value of the 'L' property, and [C1, C2, C3, C4, ...]
is the value of the 'C' property.
5-65
LC Bandpass Tee
Dialog
Box
Inductance (H)
Vector containing the inductances, in order from source to load, of
all inductors in the network. The inductance vector must contain
at least three elements. All values must be strictly positive.
Capacitance (F)
Vector containing the capacitances, in order from source to load,
of all capacitors in the network. Its length must be equal to the
length of the vector you provide in the Inductance parameter.
All values must be strictly positive.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
Examples
5-66
See the LC Bandpass Pi block for an example of an LC filter.
LC Bandpass Tee
References
[1] Ludwig, Reinhold and Pavel Bretchko, RF Circuit Design: Theory
and Applications, Prentice-Hall, 2000.
[2] Zverev, Anatol I., Handbook of Filter Synthesis, John Wiley & Sons,
1967.
See Also
General Passive Network, LC Bandpass Pi, LC Bandstop Pi, LC
Bandstop Tee, LC Highpass Pi, LC Highpass Tee, LC Lowpass Pi, LC
Lowpass Tee, Series RLC, Shunt RLC
5-67
LC Bandstop Pi
Purpose
Model LC bandstop pi network
Library
Ladder Filters sublibrary of the Physical library
Description
The LC Bandstop Pi block models the LC bandstop pi network
described in the block dialog box, in terms of its frequency-dependent
S-parameters.
For each inductor and capacitor pair in the network, the block first
calculates the ABCD-parameters at each frequency contained in the
vector of modeling frequencies. For each series pair, A = 1, B = Z, C = 0,
and D = 1, where Z is the impedance of the series pair. For each shunt
pair, A = 1, B = 0, C = Y, and D = 1, where Y is the admittance of the
shunt pair.
The LC Bandstop Pi block then cascades the ABCD-parameters for each
series and shunt pair at each of the modeling frequencies, and converts
the cascaded parameters to S-parameters using the RF Toolbox abcd2s
function.
See the Output Port block for information about determining the
modeling frequencies.
The LC bandstop pi network object is a two-port network as shown in
the circuit diagram below.
L2
L4
C2
C4
L1
L3
C1
C3
[L1, L2, L3, L4, ...] is the value of the 'L' property, and [C1, C2, C3, C4, ...]
is the value of the 'C' property.
5-68
LC Bandstop Pi
Dialog
Box
Inductance (H)
Vector containing the inductances, in order from source to load, of
all inductors in the network. The inductance vector must contain
at least three elements. All values must be strictly positive.
Capacitance (F)
Vector containing the capacitances, in order from source to load,
of all capacitors in the network. Its length must be equal to the
length of the vector you provide in the Inductance parameter.
All values must be strictly positive.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
Examples
See the LC Bandpass Pi block for an example of an LC filter.
5-69
LC Bandstop Pi
References
[1] Ludwig, Reinhold and Pavel Bretchko, RF Circuit Design: Theory
and Applications, Prentice-Hall, 2000.
[2] Zverev, Anatol I., Handbook of Filter Synthesis, John Wiley & Sons,
1967.
See Also
5-70
General Passive Network, LC Bandpass Pi, LC Bandpass Tee, LC
Bandstop Tee, LC Highpass Pi, LC Highpass Tee, LC Lowpass Pi, LC
Lowpass Tee, Series RLC, Shunt RLC
LC Bandstop Tee
Purpose
Model LC bandstop tee network
Library
Ladder Filters sublibrary of the Physical library
Description
The LC Bandstop Tee block models the LC bandstop tee network
described in the block dialog box, in terms of its frequency-dependent
S-parameters.
For each inductor and capacitor pair in the network, the block first
calculates the ABCD-parameters at each frequency contained in the
vector of modeling frequencies. For each series pair, A = 1, B = Z, C = 0,
and D = 1, where Z is the impedance of the series pair. For each shunt
pair, A = 1, B = 0, C = Y, and D = 1, where Y is the admittance of the
shunt pair.
The LC Bandstop Tee block then cascades the ABCD-parameters for
each series and shunt pair at each of the modeling frequencies, and
converts the cascaded parameters to S-parameters using the RF Toolbox
abcd2s function.
See the Output Port block for information about determining the
modeling frequencies.
The LC bandstop tee network object is a two-port network as shown in
the circuit diagram below.
L1
L3
C1
C3
L2
L4
C2
C4
[L1, L2, L3, L4, ...] is the value of the 'L' property, and [C1, C2, C3, C4, ...]
is the value of the 'C' property.
5-71
LC Bandstop Tee
Dialog
Box
Inductance (H)
Vector containing the inductances, in order from source to load, of
all inductors in the network. The inductance vector must contain
at least three elements. All values must be strictly positive.
Capacitance (F)
Vector containing the capacitances, in order from source to load,
of all capacitors in the network. Its length must be equal to the
length of the vector you provide in the Inductance parameter.
All values must be strictly positive.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
Examples
5-72
See the LC Bandpass Pi block for an example of an LC filter.
LC Bandstop Tee
References
[1] Ludwig, Reinhold and Pavel Bretchko, RF Circuit Design: Theory
and Applications, Prentice-Hall, 2000.
[2] Zverev, Anatol I., Handbook of Filter Synthesis, John Wiley & Sons,
1967.
See Also
General Passive Network, LC Bandpass Pi, LC Bandpass Tee, LC
Bandstop Pi, LC Highpass Pi, LC Highpass Tee, LC Lowpass Pi, LC
Lowpass Tee, Series RLC, Shunt RLC
5-73
LC Highpass Pi
Purpose
Model LC highpass pi network
Library
Ladder Filters sublibrary of the Physical library
Description
The LC Highpass Pi block models the LC highpass pi network
described in the block dialog box, in terms of its frequency-dependent
S-parameters.
For each inductor and capacitor in the network, the block first calculates
the ABCD-parameters at each frequency contained in the vector of
modeling frequencies. For each series circuit, A = 1, B = Z, C = 0, and
D = 1, where Z is the impedance of the series circuit. For each shunt,
A = 1, B = 0, C = Y, and D = 1, where Y is the admittance of the shunt
circuit.
The LC Highpass Pi block then cascades the ABCD-parameters for each
circuit element at each of the modeling frequencies, and converts the
cascaded parameters to S-parameters using the RF Toolbox abcd2s
function.
See the Output Port block reference page for information about
determining the modeling frequencies.
The LC highpass pi network object is a two-port network as shown in
the circuit diagram below.
C2
C1
L1
L2
L3
[L1, L2, L3, ...] is the value of the 'L' property, and [C1, C2, ...] is the
value of the 'C' property.
5-74
LC Highpass Pi
Dialog
Box
Inductance (H)
Vector containing the inductances, in order from source to load, of
all inductors in the network. The inductance vector must contain
at least two elements. All values must be strictly positive.
Capacitance (F)
Vector containing the capacitances, in order from source to load,
of all capacitors in the network. Its length must be equal to or one
less than the length of the vector you provide in the Inductance
parameter. All values must be strictly positive.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
Examples
See the LC Bandpass Pi block for an example of an LC filter.
5-75
LC Highpass Pi
References
[1] Ludwig, Reinhold and Pavel Bretchko, RF Circuit Design: Theory
and Applications, Prentice-Hall, 2000.
[2] Zverev, Anatol I., Handbook of Filter Synthesis, John Wiley & Sons,
1967.
See Also
5-76
General Passive Network, LC Bandpass Pi, LC Bandpass Tee, LC
Bandstop Pi, LC Bandstop Tee, LC Highpass Tee, LC Lowpass Pi, LC
Lowpass Tee, Series RLC, Shunt RLC
LC Highpass Tee
Purpose
Model LC highpass tee network
Library
Ladder Filters sublibrary of the Physical library
Description
The LC Highpass Tee block models the LC highpass tee network
described in the block dialog box, in terms of its frequency-dependent
S-parameters.
For each inductor and capacitor in the network, the block first calculates
the ABCD-parameters at each frequency contained in the vector of
modeling frequencies. For each series circuit, A = 1, B = Z, C = 0, and
D = 1, where Z is the impedance of the series circuit. For each shunt,
A = 1, B = 0, C = Y, and D = 1, where Y is the admittance of the shunt
circuit.
The LC Highpass Tee block then cascades the ABCD-parameters for
each circuit element at each of the modeling frequencies, and converts
the cascaded parameters to S-parameters using the RF Toolbox abcd2s
function.
See the Output Port block reference page for information about
determining the modeling frequencies.
The LC highpass tee network object is a two-port network as shown in
the circuit diagram below.
C3
C2
C1
L1
L2
L3
[L1, L2, L3, ...] is the value of the 'L' property, and [C1, C2, C3, ...] is the
value of the 'C' property.
5-77
LC Highpass Tee
Dialog
Box
Inductance (H)
Vector containing the inductances, in order from source to load, of
all inductors in the network. All values must be strictly positive.
The vector cannot be empty.
Capacitance (F)
Vector containing the capacitances, in order from source to load, of
all capacitors in the network. The capacitance vector must contain
at least two elements. Its length must be equal to or one greater
than the length of the vector you provide in the Inductance
parameter. All values must be strictly positive.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
Examples
5-78
See the LC Bandpass Pi block for an example of an LC filter.
LC Highpass Tee
References
[1] Ludwig, Reinhold and Pavel Bretchko, RF Circuit Design: Theory
and Applications, Prentice-Hall, 2000.
[2] Zverev, Anatol I., Handbook of Filter Synthesis, John Wiley & Sons,
1967.
See Also
General Passive Network, LC Bandpass Pi, LC Bandpass Tee, LC
Bandstop Pi, LC Bandstop Tee, LC Highpass Pi, LC Lowpass Pi, LC
Lowpass Tee, Series RLC, Shunt RLC
5-79
LC Lowpass Pi
Purpose
Model LC lowpass pi network
Library
Ladder Filters sublibrary of the Physical library
Description
The LC Lowpass Pi block models the LC lowpass pi network described in
the block dialog box, in terms of its frequency-dependent S-parameters.
For each inductor and capacitor in the network, the block first calculates
the ABCD-parameters at each frequency contained in the vector of
modeling frequencies. For each series circuit, A = 1, B = Z, C = 0, and
D = 1, where Z is the impedance of the series circuit. For each shunt,
A = 1, B = 0, C = Y, and D = 1, where Y is the admittance of the shunt
circuit.
The LC Lowpass Pi block then cascades the ABCD-parameters for each
circuit element at each of the modeling frequencies, and converts the
cascaded parameters to S-parameters using the RF Toolbox abcd2s
function.
See the Output Port block reference page for information about
determining the modeling frequencies.
The LC lowpass pi network object is a two-port network as shown in
the circuit diagram below.
L1
C1
L2
C2
C3
[L1, L2, ...] is the value of the 'L' property, and [C1, C2, C3, ...] is the
value of the 'C' property.
5-80
LC Lowpass Pi
Dialog
Box
Inductance (H)
Vector containing the inductances, in order from source to load, of
all inductors in the network. All values must be strictly positive.
The vector cannot be empty.
Capacitance (F)
Vector containing the capacitances, in order from source to load, of
all capacitors in the network. The capacitance vector must contain
at least two elements. Its length must be equal to or one greater
than the length of the vector you provide in the Inductance
parameter. All values must be strictly positive.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
Examples
See the LC Bandpass Pi block for an example of an LC filter.
5-81
LC Lowpass Pi
References
[1] Ludwig, Reinhold and Pavel Bretchko, RF Circuit Design: Theory
and Applications, Prentice-Hall, 2000.
[2] Zverev, Anatol I., Handbook of Filter Synthesis, John Wiley & Sons,
1967.
See Also
5-82
General Passive Network, LC Bandpass Pi, LC Bandpass Tee, LC
Bandstop Pi, LC Bandstop Tee, LC Highpass Pi, LC Highpass Tee, LC
Lowpass Tee, Series RLC, Shunt RLC
LC Lowpass Tee
Purpose
Model LC lowpass tee network
Library
Ladders Filters sublibrary of the Physical library
Description
The LC Lowpass Tee block models the LC lowpass tee network
described in the block dialog box in terms of its frequency-dependent
S-parameters.
For each inductor and capacitor in the network, the block first calculates
the ABCD-parameters at each frequency contained in the vector of
modeling frequencies. For each series circuit, A = 1, B = Z, C = 0, and
D = 1, where Z is the impedance of the series circuit. For each shunt,
A = 1, B = 0, C = Y, and D = 1, where Y is the admittance of the shunt
circuit.
The LC Lowpass Tee block then cascades the ABCD-parameters for
each circuit element at each of the modeling frequencies, and converts
the cascaded parameters to S-parameters using the RF Toolbox abcd2s
function.
See the Output Port block reference page for information about
determining the modeling frequencies.
The LC lowpass tee network object is a two-port network as shown in
the circuit diagram below.
L2
L1
C1
L3
C2
C3
[L1, L2, L3, ...] is the value of the 'L' property, and [C1, C2, C3, ...] is the
value of the 'C' property.
5-83
LC Lowpass Tee
Dialog
Box
Inductance (H)
Vector containing the inductances, in order from source to load, of
all inductors in the network. The inductance vector must contain
at least two elements. All values must be strictly positive.
Capacitance (F)
Vector containing the capacitances, in order from source to load,
of all capacitors in the network. Its length must be equal to or one
less than the length of the vector you provide in the Inductance
parameter. All values must be strictly positive.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
Examples
5-84
See the LC Bandpass Pi block for an example of an LC filter.
LC Lowpass Tee
References
[1] Ludwig, Reinhold and Pavel Bretchko, RF Circuit Design: Theory
and Applications, Prentice-Hall, 2000.
[2] Zverev, Anatol I., Handbook of Filter Synthesis, John Wiley & Sons,
1967.
See Also
General Passive Network, LC Bandpass Pi, LC Bandpass Tee, LC
Bandstop Pi, LC Bandstop Tee, LC Highpass Pi, LC Highpass Tee, LC
Lowpass Pi, Series RLC, Shunt RLC
5-85
Lowpass RF Filter
Purpose
Standard lowpass RF filters in baseband-equivalent complex form
Library
Mathematical
Description
The Lowpass RF Filter block lets you design standard analog lowpass
filters, implemented in baseband-equivalent complex form. The
following table describes the available design methods.
Design Method
Description
Butterworth
The magnitude response of a Butterworth
filter is maximally flat in the passband and
monotonic overall.
Chebyshev I
The magnitude response of a Chebyshev I filter
is equiripple in the passband and monotonic in
the stopband.
Chebyshev II
The magnitude response of a Chebyshev II
filter is monotonic in the passband and
equiripple in the stopband.
Elliptic
The magnitude response of an elliptic filter
is equiripple in both the passband and the
stopband.
Bessel
The delay of a Bessel filter is maximally flat in
the passband.
The block input must be a discrete-time complex signal.
Note This block assumes a nominal impedance of 1 ohm.
5-86
Lowpass RF Filter
Select the design of the filter from the Design method list in the dialog
box. For each design method, the block enables you to specify the filter
design parameters shown in the following table.
Design Method
Filter Design Parameters
Butterworth
Order, passband edge frequency
Chebyshev I
Order, passband edge frequency, passband
ripple
Chebyshev II
Order, stopband edge frequency, stopband
attenuation
Elliptic
Order, passband edge frequency, passband
ripple, stopband attenuation
Bessel
Order, passband edge frequency
The Lowpass RF Filter block designs the filters using the Signal
Processing Toolbox filter design functions buttap, cheb1ap, cheb2ap,
ellipap, and besselap.
Note Some RF blocks require the sample time to perform baseband
modeling calculations. To ensure the accuracy of these calculations, the
Input Port block, as well as the mathematical RF blocks, compare the
input sample time to the sample time you provide in the mask. If they
do not match, or if the input sample time is missing because the blocks
are not connected, an error message appears.
5-87
Lowpass RF Filter
Dialog
Box
The parameters displayed in the dialog box vary for different design
methods. Only some of these parameters are visible in the dialog box
at any one time.
Parameters that are tunable can be changed while the model is running.
Design method
Filter design method. The design method can be Butterworth,
Chebyshev I, Chebyshev II, Elliptic, or Bessel. Tunable.
Filter order
Order of the filter.
Passband edge frequency (Hz)
Passband edge frequency for Butterworth, Chebyshev I, elliptic,
and Bessel designs. Tunable.
Stopband edge frequency (Hz)
Stopband edge frequency for Chebyshev II designs. Tunable.
5-88
Lowpass RF Filter
Passband ripple in dB
Passband ripple for Chebyshev I and elliptic designs. Tunable.
Stopband attenuation in dB
Stopband attenuation for Chebyshev II and elliptic designs.
Tunable.
Finite impulse response filter length
Desired length of the baseband-equivalent impulse response for
the filter.
Center frequency (Hz)
Center of the modeling frequencies.
Sample time (s)
Time interval between consecutive samples of the input signal.
See Also
Amplifier, Bandpass RF Filter, Bandstop RF Filter, Highpass RF Filter,
Mixer
buttap, cheb1ap, cheb2ap, ellipap, besselap (Signal Processing
Toolbox)
5-89
Microstrip Transmission Line
Purpose
Model microstrip transmission line
Library
Transmission Lines sublibrary of the Physical library
Description
The Microstrip Transmission Line block models the microstrip
transmission line described in the block dialog in terms of its
frequency-dependent S-parameters. A microstrip transmission line is
shown here in cross-section. Its physical characteristics include the
microstrip width (w), the microstrip thickness (t), the substrate height
(d), and the relative permittivity constant ( ).
The block lets you model the transmission line as a stub or as a stubless
line.
Stubless Transmission Line
If you model a microstrip transmission line as a stubless line, the
Microstrip Transmission Line block calculates the frequency-dependent
S-parameters using the physical length of the transmission line, D, and
the complex propagation constant, k.
, where
is the attenuation coefficient and is the wave
number. The attenuation coefficient
is related to the loss, , by
5-90
Microstrip Transmission Line
where is the reduction in signal strength, in dB, per unit length.
combines both conductor loss and dielectric loss and is derived from the
physical parameters specified in the Microstrip Transmission Line block
dialog box. The wave number is related to the phase velocity, VP, by
where
, and
is the frequency dependent effective
dielectric constant. f is the vector of modeling frequencies determined
by the Output Port block. The phase velocity VP is also known as the
wave propagation velocity.
The Microstrip Transmission Line block normalizes the resulting
S-parameters to a reference impedance of 50 ohms.
Shunt and Series Stubs
If you model the transmission line as a shunt or series stub,
the Microstrip Transmission Line block first calculates the
ABCD-parameters at each frequency contained in the vector of
modeling frequencies. It then uses the abcd2s function to convert the
ABCD-parameters to S-parameters.
Shunt ABCD-Parameters
When you set the Stub mode parameter in the mask dialog box to
Shunt, the two-port network consists of a stub transmission line that
you can terminate with either a short circuit or an open circuit as
shown here.
5-91
Microstrip Transmission Line
Zin is the input impedance of the shunt circuit. The ABCD-parameters
for the shunt stub are calculated as
Series ABCD-Parameters
When you set the Stub mode parameter in the mask dialog box to
Series, the two-port network consists of a series transmission line
that you can terminate with either a short circuit or an open circuit
as shown here.
Zin is the input impedance of the series circuit. The ABCD-parameters
for the series stub are calculated as
5-92
Microstrip Transmission Line
Dialog
Box
Strip width (m)
Width of the microstrip transmission line.
5-93
Microstrip Transmission Line
Substrate height (m)
Thickness of the dielectric on which the microstrip resides.
Strip thickness (m)
Physical thickness of the microstrip.
Relative permittivity constant
Relative permittivity of the dielectric expressed as the ratio of the
permittivity of the dielectric to permittivity in free space .
Conductivity in conductor (S/m)
Conductivity of the conductor in siemens per meter.
Loss tangent in dielectric
Loss angle tangent of the dielectric.
Transmission line length (m)
Physical length of the transmission line.
Stub mode
Type of stub. Choices are Not a stub, Shunt, or Series.
Termination of stub
Stub termination for stub modes Shunt and Series. Choices are
Open or Short. This parameter becomes visible only when Stub
mode is set to Shunt or Series.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
5-94
References
[1] Gupta, K.C., G. Ramesh, I. Bahl, and P. Bhartia, Microstrip Lines
and Slotlines, Second Edition, Artech House, 1996. pp. 102-109.
See Also
Coaxial Transmission Line, Coplanar Waveguide Transmission
Line, General Passive Network, Transmission Line, Parallel-Plate
Transmission Line, Two-Wire Transmission Line
Mixer
Purpose
Complex baseband model of mixer with phase noise
Library
Mathematical
Description
The Mixer block generates a complex baseband model of a mixer, with
phase noise whose spectrum is characterized by a 1/f slope. The level
of the spectrum is specified by the noise power contained in one hertz
bandwidth offset from the carrier by a certain frequency.
Note This block assumes a nominal impedance of 1 ohm.
The block applies the phase noise to the signal as follows:
1 Generates additive white Gaussian noise (AWGN) and filters it with
a digital filter.
2 Adds the resulting noise to the angle component of the input signal.
You can view the block’s implementation of phase noise by right-clicking
the block and selecting Look under mask from the pop-up menu. This
displays the following figure.
You can view the construction of the Noise Source subsystem by
double-clicking it.
5-95
Mixer
Note Some RF blocks require the sample time to perform baseband
modeling calculations. To ensure the accuracy of these calculations, the
Input Port block, as well as the mathematical RF blocks, compare the
input sample time to the sample time you provide in the mask. If they
do not match, or if the input sample time is missing because the blocks
are not connected, an error message appears.
Dialog
Box
You can change parameters that are marked as tunable while the model
is running.
Conversion loss (dB)
Scalar specifying the conversion loss for the mixer. Tunable.
Phase noise level (dBc/Hz)
Scalar specifying the phase noise level in decibels relative to the
carrier, per hertz. Tunable.
Frequency offset (Hz)
Scalar specifying the frequency offset. Tunable.
5-96
Mixer
Initial seed
Nonnegative integer specifying the initial seed for the random
number generator the block uses to generate noise.
References
[1] Kasdin, N.J., “Discrete Simulation of Colored Noise and Stochastic
Processes and 1/(f^alpha); Power Law Noise Generation,” The
Proceedings of the IEEE, May, 1995, Vol. 83, No. 5.
See Also
Amplifier, Bandpass RF Filter, Bandstop RF Filter, Highpass RF Filter,
Lowpass RF Filter
5-97
Output Port
Purpose
Connection block from RF physical blocks to Simulink environment
Library
Input/Output Ports sublibrary of the Physical library
Description
The Output Port block produces the baseband-equivalent time-domain
response of an input signal traveling through a series of RF physical
components. The Output Port block
1 Partitions the RF physical components into linear and nonlinear
subsystems.
2 Extracts the complex impulse response of the linear subsystem for
baseband-equivalent modeling of the RF linear system.
3 Extracts the nonlinear AMAM/AMPM modeling for RF nonlinearity.
The Output Port block also serves as a connecting port from an RF
physical part of the model to the Simulink, or mathematical, part of the
model. For more information about how the Output Port block converts
the RF Blockset physical modeling environment signals to mathematical
Simulink signals, see “Converting to and from Simulink Signals” on
page A-15. For more information about connecting mathematical and
physical parts of a model, see Chapter 2, “Modeling an RF System”.
Note Some RF blocks require the sample time to perform baseband
modeling calculations. To ensure the accuracy of these calculations, the
Input Port block, as well as the mathematical RF blocks, compare the
input sample time to the sample time you provide in the mask. If they
do not match, or if the input sample time is missing because the blocks
are not connected, an error message appears.
Linear Subsystem
For the linear subsystem, the Output Port block uses the Input Port
block parameters and the interpolated S-parameters calculated by each
5-98
Output Port
of the cascaded physical blocks to calculate the baseband-equivalent
impulse response. Specifically, it
1 Determines the modeling frequencies f as an N-element vector. The
modeling frequencies are a function of the center frequency fc, the
sample time ts, and the finite impulse response filter length N, all of
which you specify in the Input Port block dialog box.
The nth element of f, fn, is given by
fn = fmin +
n −1
n = 1,..., N
ts N
where
fmin = fc −
1
2ts
2 Calculates the passband transfer function for the frequency range as
H( f ) =
VL ( f )
VS ( f )
where VS and VL are the source and load voltages, and f represents
the modeling frequencies. More specifically,
H( f ) =
S21 * (1 + Γ l ) * (1 − Γ s )
2 * (1 − S22 * Γ l ) (1 − Γin * Γ s )
5-99
Output Port
where
Γl =
Zl − Zo
Zl + Zo
Γs =
Zs − Zo
Zs + Zo
⎛
⎞
Γl
Γin = S11 + ⎜⎜ S12 * S21 *
⎟
(1 − S22 * Γ l ) ⎟⎠
⎝
and
• ZS is the source impedance.
• ZL is the load impedance.
• Sij are the S-parameters of a two-port network.
5-100
Output Port
The passband transfer function is shown in the following figure.
Specify these parameters in the Input Port dialog box:
Passband Spectrum of a Modulated RF Carrier
Finite impulse response filter length = N
Center frequency = fc
Sample time = ts
Magnitude
1/(ts*N)
Index = n
Frequency
fmin
Index = 1
fc
1/ts
fn
fmax
Index = N
3 Translates the passband transfer function to baseband as
,
where fc is the specified center frequency.
5-101
Output Port
The baseband transfer function is shown in the following figure.
Baseband-Equivalent Spectrum
Magnitude
Centered at zero
1/2ts
-1/2ts
Frequency
1/ts
4 Obtains the baseband-equivalent impulse response by calculating the
inverse FFT of the baseband transfer function. For faster simulation,
the block calculates the IFFT using the next power of 2 greater than
the specified finite impulse response filter length. Then, it truncates
the impulse response to a length equal to the filter length specified.
For the linear subsystem, the Output Port block uses the calculated
impulse response as input to the Signal Processing Blockset Digital
Filter block to determine the output.
Nonlinear Subsystem
The nonlinear subsystem is implemented by AM/AM and AM/PM
nonlinear models, as shown in the figure below.
5-102
Output Port
The nonlinearities of AM/AM and AM/PM conversions are extracted
from the power data of an amplifier or mixer by the equations
where AMin is the AM of the input voltage, AMout and PMout are the
AM and PM of the output voltage, Rs, is the source resistance (50
ohms), Rl is the load resistance (50 ohms), Pin is the input power, Pout
is the output power, and Phase is the phase shift between the input
and output voltage.
Note You can provide power data via a .amp file. See “AMP File
Format” in the RF Toolbox documentation for information about this
format.
5-103
Output Port
The following figure shows the original power data of an amplifier.
5-104
Output Port
This figure shows the extracted AM/AM nonlinear conversion.
Dialog
Box
Load impedance
Load impedance of the RF network described in the physical
model to which it connects.
5-105
Output Port
Plot the selected parameters of the RF system
This parameter and the associated plotting parameters shown
below become visible if you display the Output Port mask after
you run the model. For more information about plotting, see
Chapter 3, “Plotting Model Data”.
See Also
Input Port
s2y (RF Toolbox)
5-106
Parallel-Plate Transmission Line
Purpose
Model parallel-plate transmission line
Library
Transmission Lines sublibrary of the Physical library
Description
The Parallel-Plate Transmission Line block models the parallel-plate
transmission line described in the block dialog box in terms of its
frequency-dependent S-parameters. A parallel-plate transmission line
is shown here in cross-section. Its physical characteristics include the
plate width and the plate separation .
The block lets you model the transmission line as a stub or as a stubless
line.
Stubless Transmission Line
If you model a parallel-plate transmission line as a stubless
line, the Parallel-Plate Transmission Line block calculates the
frequency-dependent S-parameters using the physical length of the
transmission line, D, and the complex propagation constant, k.
k can be expressed in terms of the resistance (R), inductance (L),
conductance (G), and capacitance (C) per unit length (meters) as
5-107
Parallel-Plate Transmission Line
where
In these equations,
is the conductivity in the conductor and
is
the conductivity in the dielectric. is the permeability of the dielectric,
is its permittivity, and skin depth is calculated as
. f is
the vector of modeling frequencies for the specified parameters. See the
Output Port block reference page for information about determining
the modeling frequencies.
The Parallel-Plate Transmission Line block normalizes the resulting
S-parameters to a reference impedance of 50 ohms.
Shunt and Series Stubs
If you model the transmission line as a shunt or series stub,
the Parallel-Plate Transmission Line block first calculates the
ABCD-parameters at each frequency contained in the vector of
modeling frequencies. It then uses the abcd2s function to convert the
ABCD-parameters to S-parameters.
Shunt ABCD-Parameters
When you set the Stub mode parameter in the mask dialog box to
Shunt, the two-port network consists of a stub transmission line that
you can terminate with either a short circuit or an open circuit as
shown here.
5-108
Parallel-Plate Transmission Line
Zin is the input impedance of the shunt circuit. The ABCD-parameters
for the shunt stub are calculated as
Series ABCD-Parameters
When you set the Stub mode parameter in the mask dialog box to
Series, the two-port network consists of a series transmission line
that you can terminate with either a short circuit or an open circuit
as shown here.
Zin is the input impedance of the series circuit. The ABCD-parameters
for the series stub are calculated as
5-109
Parallel-Plate Transmission Line
Dialog
Box
Plate width (m)
Physical width of the parallel-plate transmission line.
5-110
Parallel-Plate Transmission Line
Plate separation (m)
Thickness of the dielectric separating the plates.
Relative permeability constant
Relative permeability of the dielectric expressed as the ratio of the
permeability of the dielectric to permeability in free space .
Relative permittivity constant
Relative permittivity of the dielectric expressed as the ratio of the
permittivity of the dielectric to permittivity in free space .
Conductivity in conductor (S/m)
Conductivity of the conductor in siemens per meter.
Conductivity in dielectric (S/m)
Conductivity of the dielectric in siemens per meter.
Transmission line length (m)
Physical length of the transmission line.
Stub mode
Type of stub. Choices are Not a stub, Shunt, or Series.
Termination of stub
Stub termination for stub modes Shunt and Series. Choices are
Open or Short. This parameter becomes visible only when Stub
mode is set to Shunt or Series.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
References
[1] Ludwig, Reinhold and Pavel Bretchko, RF Circuit Design: Theory
and Applications, Prentice-Hall, 2000.
See Also
Coaxial Transmission Line, Coplanar Waveguide Transmission Line,
General Passive Network, Transmission Line, Microstrip Transmission
Line, Two-Wire Transmission Line
5-111
RLCG Transmission Line
Purpose
Model RLCG transmission line
Library
Transmission Lines sublibrary of the Physical library
Description
The RLCG Transmission Line block models the RLCG transmission line
described in the block dialog box in terms of its frequency-dependent
resistance, inductance, capacitance, and conductance. The transmission
line, which can be lossy or lossless, is treated as a two-port linear
network.
I(z)
I(z’)
L
R
V(z)
G
V(z’)
z’
z
where
C
.
The block lets you model the transmission line as a stub or as a stubless
line.
Stubless Transmission Line
If you model a RLCG transmission line as a stubless line, the
RLCG Transmission Line block calculates the frequency-dependent
S-parameters using the physical length of the transmission line, D, and
the complex propagation constant, k.
5-112
RLCG Transmission Line
k can be expressed in terms of the resistance (R), inductance (L),
conductance (G), and capacitance (C) per unit length (meters) as
The RLCG Transmission Line block normalizes the resulting
S-parameters to a reference impedance of 50 ohms.
Shunt and Series Stubs
If you model the transmission line as a shunt or series stub, the RLCG
Transmission Line block first calculates the ABCD-parameters at each
frequency contained in the vector of modeling frequencies. It then uses
the abcd2s function to convert the ABCD-parameters to S-parameters.
Shunt ABCD-Parameters
When you set the Stub mode parameter in the mask dialog box to
Shunt, the two-port network consists of a stub transmission line that
you can terminate with either a short circuit or an open circuit as
shown here.
Zin is the input impedance of the shunt circuit. The ABCD-parameters
for the shunt stub are calculated as
5-113
RLCG Transmission Line
Series ABCD-Parameters
When you set the Stub mode parameter in the mask dialog box to
Series, the two-port network consists of a series transmission line
that you can terminate with either a short circuit or an open circuit
as shown here.
Zin is the input impedance of the series circuit. The ABCD-parameters
for the series stub are calculated as
5-114
RLCG Transmission Line
Dialog
Box
Resistance per length (ohms/m)
Vector of resistance values in ohms per meter.
Inductance per length (H/m)
Vector of inductance values in henries per meter.
Capacitance per length (F/m)
Vector of capacitance values in farads per meter.
Conductance per length (S/m)
Vector of conductance values in siemens per meter.
5-115
RLCG Transmission Line
Frequency (Hz)
Vector of frequency values at which the resistance, inductance,
capacitance, and conductance values are known.
Interpolation method
Specify the interpolation method the block uses to calculate the
parameter values at the modeling frequencies. Your choices are
Linear, Spline, or Cubic.
Transmission line length (m)
Physical length of the transmission line.
Stub mode
Type of stub. Your choices are Not a stub, Shunt, or Series.
Termination of stub
Stub termination for stub modes Shunt and Series. Choices are
Open or Short. This parameter becomes visible only when Stub
mode is set to Shunt or Series.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
References
[1] Ludwig, Reinhold and Pavel Bretchko, RF Circuit Design: Theory
and Applications, Prentice-Hall, 2000.
See Also
Coaxial Transmission Line, Coplanar Waveguide Transmission
Line, General Passive Network, Parallel-Plate Transmission Line,
Transmission Line, Microstrip Transmission Line, Two-Wire
Transmission Line
5-116
S-Parameters Amplifier
Purpose
Model nonlinear amplifier using its S-parameters
Library
Amplifiers sublibrary of the Physical library
Description
The S-Parameters Amplifier block models the nonlinear amplifier
described in the block dialog box, in terms of its frequency-dependent
S-parameters, their frequencies, and the reference impedance of the
S-parameters. The block also takes into account the IP3 value and the
noise figure.
In the S-parameters field of the block dialog box, provide the
S-parameters for each of M frequencies as a 2-by-2-by-M array. In the
Frequency field, specify the frequencies for the S-parameters as an
M-element vector. The elements of the frequencies vector must be in
the same order as the S-parameters. All frequencies must be positive.
For example, the following figure shows the correspondence between
the S-parameters array and the vector of frequencies.
The S-Parameters Amplifier block interpolates the given S-parameters
to determine their values at the modeling frequencies. The modeling
frequencies are determined by the Output Port block. See Appendix A,
“RF Blockset Algorithms” for more details.
5-117
S-Parameters Amplifier
Dialog
Box
S-Parameters
S-parameters for a nonlinear amplifier in a 2-by-2-by-M array. M
is the number of S-parameters.
Frequency (Hz)
Frequencies of the S-parameters as an M-element vector. The
order of the frequencies must correspond to the order of the
S-parameters in S-Parameters. All frequencies must be positive.
5-118
S-Parameters Amplifier
Reference impedance
Reference impedance of the S-parameters as a scalar or a vector
of length M. The value of this parameter can be real or complex. If
you provide a scalar, that value is applied to all frequencies.
Interpolation method
Method used to interpolate the given S-parameters over the range
of frequencies. Interpolation can be Cubic, Linear (default), or
Spline.
IP3 type
Type of third-order intercept point. The value can be IIP3 (input
intercept point) or OIP3 (output intercept point).
IIP3 (dBm)
Input power intercept point as a scalar value. This field becomes
visible if you select IIP3 as the IP3 type.
OIP3 (dBm)
Output power intercept point as a scalar value. This field becomes
visible if you select OIP3 as the IP3 type.
Noise figure (dB)
Scalar ratio of the available signal-to-noise power ratio at the
input to the available signal-to-noise power ratio at the output,
((Si/Ni)/(So/No)).
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
Examples
Plotting Parameters with the S-Parameters Amplifier Block
The following example specifies S-parameters [-.33+.71i, -.03i; 8.12-.02i,
-.37-.37i] and [0.16+.20i, -.03-.04i; 7.71-8.04i, -.70-.12i] at frequencies
2.0 GHz and 2.1 GHz respectively, with a reference impedance of 50
ohms. It uses the MATLAB cat function to create the 2-by-2-by-2
S-parameters array.
5-119
S-Parameters Amplifier
cat(3,[-.33+0.71i,
-.03i; 8.12-.02i, -.37-.37i],...
[ .16+0.20i, -.03-.04i; 7.71-8.04i, -.70-.12i])
The plot parameters in the dialog box request an X-Y Plane plot of the
S11 parameters in the frequency range 1.8 to 2.3 GHz.
5-120
S-Parameters Amplifier
See Also
General Amplifier, Output Port, Y-Parameters Amplifier, Z-Parameters
Amplifier
interp1 (MATLAB)
5-121
S-Parameters Mixer
Purpose
Model mixer using its S-parameters
Library
Mixer sublibrary of the Physical library
Description
The S-Parameters Mixer block models the nonlinear mixer described in
the block dialog box, in terms of its frequency-dependent S-parameters,
their frequencies, and the reference impedance of the S-parameters.
The block also takes phase noise into account.
The S21 parameter values describe the conversion gain as a function
of frequency, referred to the mixer input frequency. The other
S-parameters also refer to the mixer input frequency.
The S-Parameters Mixer block interpolates the given S-parameters
to determine their values at the modeling frequencies. The modeling
frequencies are determined by the Output Port block. See Appendix A,
“RF Blockset Algorithms” for more details.
The RF Blockset computes the normalized reflected amplitude at the
mixer input ( Er1 ) and at the mixer output ( Er2 ) from the interpolated
S-parameters as
Er1 ( fin ) = S11 ( fin ) Ei1 ( fin ) + S12 ( fin ) Ei2 ( fout )
Er 2 ( fout ) = S21 ( fin ) Ei1 ( fin ) + S22 ( fin ) Ei2 ( fout )
where
•
fin and f out are the mixer input and output frequencies, respectively.
• Ei1 and Ei2 are the normalized incident amplitudes at the mixer
input and output, respectively.
The interpolated S21 parameter values describe the conversion gain as
a function of frequency, referred to the mixer input frequency.
5-122
S-Parameters Mixer
Dialog
Box
S-Parameters
S-parameters for a nonlinear mixer in a 2-by-2-by-M array. M is
the number of S-parameters.
5-123
S-Parameters Mixer
Frequency (Hz)
Frequencies of the S-parameters as an M-element vector. The
order of the frequencies must correspond to the order of the
S-parameters in S-Parameters. All frequencies must be positive.
The following figure shows the correspondence between the
S-parameters array and the vector of frequencies.
Reference impedance
Reference impedance of the S-parameters as a scalar or a vector
of length M. The value of this parameter can be real or complex. If
you provide a scalar, that value is applied to all frequencies.
Interpolation method
Method used to interpolate the given S-parameters over the range
of frequencies. Interpolation can be Linear (default), Spline, or
Cubic.
Type
Type of mixer. Choices are Downconverter (default) and
Upconverter.
LO frequency (Hz)
Local oscillator frequency. If you choose Downconverter, the RF
Blockset computes the mixer output frequency,
f out , from the
mixer input frequency, f in , and the local oscillator frequency, f lo ,
. If you choose Upconverter,
.
as
5-124
S-Parameters Mixer
Note The mixer output frequency must be positive. This means
that if you choose a downconverting mixer,
than
fin must be greater
flo . Otherwise, an error appears.
IP3 type
Type of third-order intercept point. The value can be IIP3 (input
intercept point) or OIP3 (output intercept point).
IIP3 (dBm)
Input power intercept point as a scalar value. This field becomes
visible if you select IIP3 as the IP3 type.
OIP3 (dBm)
Output power intercept point as a scalar value. This field becomes
visible if you select OIP3 as the IP3 type.
Noise figure (dB)
Scalar ratio of the available signal-to-noise power ratio at the
input to the available signal-to-noise power ratio at the output
(Si/Ni)/(So/No).
Phase noise frequency offset (Hz)
Vector specifying the frequency offset.
Phase noise level (dBc/Hz)
Vector specifying the phase noise level.
Note For information about plotting the mixer parameters, see
Chapter 3, “Plotting Model Data”.
See Also
General Mixer, Output Port, Y-Parameters Mixer, Z-Parameters Mixer
5-125
S-Parameters Passive Network
Purpose
Model passive network using its S-parameters
Library
Black Box Elements sublibrary of the Physical library
Description
The S-Parameters Passive Network block models the two-port passive
network described in the block dialog box, in terms of its S-parameters,
their frequencies, and the reference impedance of the S-parameters.
In the S-Parameters field of the block dialog box, provide the
S-parameters for each of M frequencies as a 2-by-2-by-M array. In the
Frequency field, specify the frequencies for the S-parameters as an
M-element vector. The elements of the vector must be in the same order
as the S-parameters. All frequencies must be positive. For example, the
following figure shows the correspondence between the S-parameters
array and the vector of frequencies.
The S-Parameters Passive Network block interpolates the given
S-parameters to determine their values at the modeling frequencies.
The modeling frequencies are determined by the Output Port block. See
Appendix A, “RF Blockset Algorithms” for more details.
5-126
S-Parameters Passive Network
Dialog
Box
S-Parameters
S-parameters for a two-port passive network in a 2-by-2-by-M
array. M is the number of S-parameters.
Frequency (Hz)
Frequencies of the S-parameters as an M-element vector. The
order of the frequencies must correspond to the order of the
S-parameters in S-Parameters. All frequencies must be positive.
Reference impedance
Reference impedance of the network as a scalar or a vector of
length M. The value of this parameter can be real or complex. If
you provide a scalar, that value is applied to all frequencies.
5-127
S-Parameters Passive Network
Interpolation method
Method used to interpolate the given S-parameters over the range
of frequencies. Interpolation can be Cubic, Linear (default), or
Spline.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
Examples
Plotting Parameters with the S-Parameters Passive Network
Block
The following example specifies S-parameters [-.96-.23i, .03-.12i;
.03-.12i, -.96-.23i] and [-.96-.11i, .02-.21i; .02-.21i, -.96-.11i] at
frequencies 2.0 GHz and 2.1 GHz respectively. It uses the MATLAB cat
function to create the 2-by-2-by-2 S-parameters array.
cat(3,[-.96-.23i, .03-.12i; .03-.12i, -.96-.23i],...
[-.96-.11i, .02-.21i; .02-.21i, -.96-.11i])
You could also use the MATLAB reshape function. The following
statement produces the same result as the one shown above.
reshape([-.96-.23i;.03-.12i;.03-.12i;-.96-.23i;...
-.96-.11i;.02-.21i;.02-.21i;-.96-.11i],2,2,2)
5-128
S-Parameters Passive Network
The plot parameters in the dialog box request an X-Y Plane plot of the
S21 S-parameter magnitudes, in decibels, in the frequency range 1.9
to 2.2 GHz.
5-129
S-Parameters Passive Network
See Also
General Circuit Element, General Passive Network, Output Port,
Y-Parameters Passive Network, Z-Parameters Passive Network
interp1 (MATLAB)
5-130
Series RLC
Purpose
Model series RLC network
Library
Ladders Filters sublibrary of the Physical library
Description
The Series RLC block models the series RLC network described in the
block dialog box, in terms of its frequency-dependent S-parameters.
For the given resistance, inductance, and capacitance, the block first
calculates the ABCD-parameters at each frequency contained in the
vector of modeling frequencies, and then converts the ABCD-parameters
to S-parameters using the RF Toolbox abcd2s function. See the
Output Port block reference page for information about determining
the modeling frequencies.
For this circuit, A = 1, B = Z, C = 0, and D = 1, where
and
.
The series RLC object is a two-port network as shown in the circuit
diagram below.
R
L
C
5-131
Series RLC
Dialog
Box
Resistance (ohms)
Scalar value for the resistance. The value must be nonnegative.
Inductance (H)
Scalar value for the inductance. The value must be nonnegative.
Capacitance (F)
Scalar value for the capacitance. The value must be nonnegative.
5-132
Series RLC
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
See Also
General Passive Network, LC Bandpass Pi, LC Bandpass Tee, LC
Bandstop Pi, LC Bandstop Tee, LC Highpass Pi, LC Highpass Tee, LC
Lowpass Pi, LC Lowpass Tee, Shunt RLC
5-133
Shunt RLC
Purpose
Model shunt RLC network
Library
Ladders Filters sublibrary of the Physical library
Description
The Shunt RLC block models the shunt RLC network described in the
block dialog box, in terms of its frequency-dependent S-parameters.
For the given resistance, inductance, and capacitance, the block first
calculates the ABCD-parameters at each frequency contained in the
vector of modeling frequencies, and then converts the ABCD-parameters
to S-parameters using the RF Toolbox abcd2s function. See the
Output Port block reference page for information about determining
the modeling frequencies.
For this circuit, A = 1, B = 0, C = Y, and D = 1, where
and
.
The shunt RLC object is a two-port network as shown in the circuit
diagram below.
R
5-134
L
C
Shunt RLC
Dialog
Box
Resistance (ohms)
Scalar value for the resistance. The value must be nonnegative.
Inductance (H)
Scalar value for the inductance. The value must be nonnegative.
Capacitance (F)
Scalar value for the capacitance. The value must be nonnegative.
5-135
Shunt RLC
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
See Also
5-136
General Passive Network, LC Bandpass Pi, LC Bandpass Tee, LC
Bandstop Pi, LC Bandstop Tee, LC Highpass Pi, LC Highpass Tee, LC
Lowpass Pi, LC Lowpass Tee, Series RLC
Transmission Line
Purpose
Model general transmission line
Library
Transmission Lines sublibrary of the Physical library
Description
The Transmission Line block models the transmission line described
in the block dialog box in terms of its physical parameters. The
transmission line, which can be lossy or lossless, is treated as a two-port
linear network.
The block enables you to model the transmission line as a stub or as
a stubless line.
Stubless Transmission Line
If you model the transmission line as a stubless line, the Transmission
Line block calculates the frequency-dependent S-parameters using the
physical length of the transmission line, D, and the complex propagation
constant, k.
, where
is the attenuation coefficient and is the wave
number. The attenuation coefficient
is related to the loss, , by
and the wave number
is related to the phase velocity, VP, by
5-137
Transmission Line
where is the vector of modeling frequencies determined by the Output
Port block. The phase velocity VP is also known as the wave propagation
velocity.
The Transmission Line block normalizes the resulting S-parameters to
a reference impedance of 50 ohms.
Shunt and Series Stubs
If you model the transmission line as a shunt or series stub, the
Transmission Line block first calculates the ABCD-parameters at each
frequency contained in the vector of modeling frequencies. It then uses
the abcd2s function to convert the ABCD-parameters to S-parameters.
Shunt ABCD-Parameters
When you set the Stub mode parameter in the mask dialog box to
Shunt, the two-port network consists of a stub transmission line that
you can terminate with either a short circuit or an open circuit as
shown here.
Zin is the input impedance of the shunt circuit. The ABCD-parameters
for the shunt stub are calculated as
5-138
Transmission Line
Series ABCD-Parameters
When you set the Stub mode parameter in the mask dialog box to
Series, the two-port network consists of a series transmission line
that you can terminate with either a short circuit or an open circuit
as shown here.
Zin is the input impedance of the series circuit. The ABCD-parameters
for the series stub are calculated as
5-139
Transmission Line
Dialog
Box
Characteristic impedance
Characteristic impedance of the transmission line. The value can
be complex.
Phase velocity (m/s)
Propagation velocity of a uniform plane wave on the transmission
line.
Loss (dB/m)
Reduction in strength of the signal as it travels over the
transmission line. Must be positive.
5-140
Transmission Line
Transmission line length (m)
Physical length of the transmission line.
Stub mode
Type of stub. Choices are Not a stub, Shunt, or Series.
Termination of stub
Stub termination for stub modes Shunt and Series. Choices are
Open or Short. This parameter becomes visible only when Stub
mode is set to Shunt or Series.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
References
[1] Ludwig, Reinhold and Pavel Bretchko, RF Circuit Design: Theory
and Applications, Prentice-Hall, 2000.
See Also
Coaxial Transmission Line, Coplanar Waveguide Transmission Line,
General Passive Network, Microstrip Transmission Line, Parallel-Plate
Transmission Line, Two-Wire Transmission Line
5-141
Two-Wire Transmission Line
Purpose
Model two-wire transmission line
Library
Transmission Lines sublibrary of the Physical library
Description
The Two-Wire Transmission Line block models the two-wire
transmission line described in the block dialog box in terms of its
frequency-dependent S-parameters. A parallel-plate transmission line
is shown here in cross-section. Its physical characteristics include the
radius of the wires a, and the distance between the wire centers D.
The block enables you to model the transmission line as a stub or as
a stubless line.
Stubless Transmission Line
If you model a parallel-plate transmission line as a stubless line, the
Two-Wire Transmission Line block calculates the frequency-dependent
S-parameters using the physical length of the transmission line, D, and
the complex propagation constant, k.
k can be expressed in terms of the resistance (R), inductance (L),
conductance (G), and capacitance (C) per unit length (meters) as
5-142
Two-Wire Transmission Line
where
In these equations,
is the conductivity in the conductor and
is
the conductivity in the dielectric. is the permeability of the dielectric,
is its permittivity, and skin depth is calculated as
. f is
the vector of modeling frequencies for the specified parameters. See the
Output Port block reference page for information about determining
the modeling frequencies.
The Two-Wire Transmission Line block normalizes the resulting
S-parameters to a reference impedance of 50 ohms.
Shunt and Series Stubs
If you model the transmission line as a shunt or series stub,
the Two-Wire Transmission Line block first calculates the
ABCD-parameters at each frequency contained in the vector of
modeling frequencies. It then uses the abcd2s function to convert the
ABCD-parameters to S-parameters.
Shunt ABCD-Parameters
When you set the Stub mode parameter in the mask dialog box to
Shunt, the two-port network consists of a stub transmission line that
you can terminate with either a short circuit or an open circuit as
shown here.
5-143
Two-Wire Transmission Line
Zin is the input impedance of the shunt circuit. The ABCD-parameters
for the shunt stub are calculated as
Series ABCD-Parameters
When you set the Stub mode parameter in the mask dialog box to
Series, the two-port network consists of a series transmission line
that you can terminate with either a short circuit or an open circuit
as shown here.
Zin is the input impedance of the series circuit. The ABCD-parameters
for the series stub are calculated as
5-144
Two-Wire Transmission Line
Dialog
Box
Wire radius (m)
Radius of the conducting wires of the two-wire transmission line.
5-145
Two-Wire Transmission Line
Wire separation (m)
Physical distance between the wires.
Relative permeability constant
Relative permeability of the dielectric expressed as the ratio of the
permeability of the dielectric to permeability in free space .
Relative permittivity constant
Relative permittivity of the dielectric expressed as the ratio of the
permittivity of the dielectric to permittivity in free space .
Conductivity in conductor (S/m)
Conductivity of the conductor in siemens per meter.
Conductivity in dielectric (S/m)
Conductivity of the dielectric in siemens per meter.
Transmission line length (m)
Physical length of the transmission line.
Stub mode
Type of stub. Choices are Not a stub, Shunt, or Series.
Termination of stub
Stub termination for stub modes Shunt and Series. Choices are
Open or Short. This parameter becomes visible only when Stub
mode is set to Shunt or Series.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
References
[1] Ludwig, Reinhold and Pavel Bretchko, RF Circuit Design: Theory
and Applications, Prentice-Hall, 2000.
See Also
Coaxial Transmission Line, Coplanar Waveguide Transmission Line,
General Passive Network, Transmission Line, Microstrip Transmission
Line, Parallel-Plate Transmission Line
5-146
Y-Parameters Amplifier
Purpose
Model nonlinear amplifier using its Y-parameters
Library
Amplifiers sublibrary of the Physical library
Description
The Y-Parameters Amplifier block models the nonlinear amplifier
described in the block dialog box, in terms of its frequency-dependent
Y-parameters and their frequencies. The block also takes into account
the IP3 value and the noise figure.
In the Y-Parameters field of the block dialog box, provide the
Y-parameters for each of M frequencies as a 2-by-2-by-M array. In the
Frequency field, specify the frequencies for the Y-parameters as an
M-element vector. The elements of the frequencies vector must be in
the same order as the Y-parameters. All frequencies must be positive.
For example, the following figure shows the correspondence between
the Y-parameters array and the vector of frequencies.
The Y-Parameters Amplifier block uses the RF Toolbox y2s function
to convert the Y-parameters to S-parameters, and then interpolates
the resulting S-parameters to determine their values at the modeling
frequencies. The modeling frequencies are determined by the Output
Port block. See Appendix A, “RF Blockset Algorithms” for more details.
5-147
Y-Parameters Amplifier
Dialog
Box
Y-Parameters
Y-parameters for a nonlinear amplifier in a 2-by-2-by-M array. M
is the number of Y-parameters.
Frequency (Hz)
Frequencies of the Y-parameters as an M-element vector. The
order of the frequencies must correspond to the order of the
Y-parameters in Y-Parameters. All frequencies must be positive.
Interpolation method
Method used to interpolate the S-parameters, as derived from the
Y-parameters, over the range of frequencies. Interpolation can be
Cubic, Linear (default), or Spline.
5-148
Y-Parameters Amplifier
IP3 type
Type of third-order intercept point. The value can be IIP3 (input
intercept point) or OIP3 (output intercept point).
IIP3 (dBm)
Input power intercept point as a scalar value. This field becomes
visible if you select IIP3 as the IP3 type.
OIP3 (dBm)
Output power intercept point as a scalar value. This field becomes
visible if you select OIP3 as the IP3 type.
Noise figure (dB)
Scalar ratio of the available signal-to-noise power ratio at the
input to the available signal-to-noise power ratio at the output,
(Si/Ni)/(So/No).
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
Examples
Plotting Parameters with the Y-Parameters Amplifier Block
The following example specifies Y-parameters [-.06+.58i, -.08i;
1.14-1.82i, -.07+.28i] and [.02-.21i, 0.03i; -.21+.72i, .03-.11i] at
frequencies 2.0 GHz and 2.1 GHz respectively. It uses the MATLAB cat
function to create the 2-by-2-by-2 Y-parameters array
cat(3,[-.06+.58i, -.08i; 1.14-1.82i, -.07+.28i],...
[ .02-.21i, 0.03i; -.21+.72i, .03-.11i])
5-149
Y-Parameters Amplifier
The plot parameters in the dialog box request an X-Y plane plot of the
S11 parameters in the frequency range 1.8 to 2.3 GHz.
5-150
Y-Parameters Amplifier
See Also
General Amplifier, Output Port, S-Parameters Amplifier, Z-Parameters
Amplifier
y2s (RF Toolbox)
interp1 (MATLAB)
5-151
Y-Parameters Mixer
Purpose
Model mixer using its Y-parameters
Library
Mixer sublibrary of the Physical library
Description
The Y-Parameters Mixer block models the nonlinear mixer described in
the block dialog box in terms of its frequency-dependent Y-parameters,
their frequencies, and the reference impedance of the Y-parameters.
The block also takes phase noise into account.
The Y-parameter values all refer to the mixer input frequency.
The Y-Parameters Mixer block uses the RF Toolbox y2s function to
convert the Y-parameters to S-parameters and then interpolates the
resulting S-parameters to determine their values at the modeling
frequencies. The modeling frequencies are determined by the Output
Port block. See Appendix A, “RF Blockset Algorithms” for more details.
The RF Blockset computes the normalized reflected amplitude at the
mixer input ( Er1 ) and at the mixer output ( Er2 ) from the interpolated
S-parameters as
Er1 ( fin ) = S11 ( fin ) Ei1 ( fin ) + S12 ( fin ) Ei2 ( fout )
Er 2 ( fout ) = S21 ( fin ) Ei1 ( fin ) + S22 ( fin ) Ei2 ( fout )
where
•
fin and f out are the mixer input and output frequencies, respectively.
• Ei1 and Ei2 are the normalized incident amplitudes at the mixer
input and output, respectively.
The interpolated S21 parameter values describe the conversion gain as
a function of frequency, referred to the mixer input frequency.
5-152
Y-Parameters Mixer
Dialog
Box
Y-Parameters
Y-parameters for a nonlinear mixer in a 2-by-2-by-M array. M
is the number of Y-parameters.
5-153
Y-Parameters Mixer
Frequency (Hz)
Frequencies of the Y-parameters as an M-element vector. The
order of the frequencies must correspond to the order of the
Y-parameters in Y-Parameters. All frequencies must be positive.
The following figure shows the correspondence between the
Y-parameters array and the vector of frequencies.
Interpolation method
Method used to interpolate the S-parameters, as derived from the
Y-parameters, over the range of frequencies. Interpolation can be
Linear (default), Spline, or Cubic.
Type
Type of mixer. Choices are Downconverter (default) and
Upconverter.
LO frequency (Hz)
Local oscillator frequency. If you choose Downconverter, the RF
Blockset computes the mixer output frequency,
f out , from the
mixer input frequency, f in , and the local oscillator frequency, f lo ,
. If you choose Upconverter,
.
as
5-154
Y-Parameters Mixer
Note The mixer output frequency must be positive. This means
that if you choose a downconverting mixer,
than
fin must be greater
flo . Otherwise, an error appears.
IP3 type
Type of third-order intercept point. The value can be IIP3 (input
intercept point) or OIP3 (output intercept point).
IIP3 (dBm)
Input power intercept point as a scalar value. This field becomes
visible if you select IIP3 as the IP3 type.
OIP3 (dBm)
Output power intercept point as a scalar value. This field becomes
visible if you select OIP3 as the IP3 type.
Noise figure (dB)
Scalar ratio of the available signal-to-noise power ratio at the
input to the available signal-to-noise power ratio at the output,
(Si/Ni)/(So/No).
Phase noise frequency offset (Hz)
Vector specifying the frequency offset.
Phase noise level (dBc/Hz)
Vector specifying the phase noise level.
Note For information about plotting the mixer parameters, see
Chapter 3, “Plotting Model Data”.
See Also
General Mixer, Output Port, S-Parameters Mixer, Z-Parameters Mixer
5-155
Y-Parameters Passive Network
Purpose
Model passive network using its Y-parameters
Library
Black Box Elements sublibrary of the Physical library
Description
The Y-Parameters Passive Network block models the two-port passive
network described in the block dialog box, in terms of its Y-parameters
and their associated frequencies.
In the Y-Parameters field of the block dialog box, provide the
Y-parameters for each of M frequencies as a 2-by-2-by-M array. In the
Frequency field, specify the frequencies for the Y-parameters as an
M-element vector. The elements of the vector must be in the same order
as the Y-parameters. All frequencies must be positive. For example, the
following figure shows the correspondence between the Y-parameters
array and the vector of frequencies.
The Y-Parameters Passive Network block uses the RF Toolbox y2s
function to convert the Y-parameters to S-parameters, and then
interpolates the resulting S-parameters to determine their values at
the modeling frequencies. The modeling frequencies are determined
by the Output Port block. See Appendix A, “RF Blockset Algorithms”
for more details.
5-156
Y-Parameters Passive Network
Dialog
Box
Y-Parameters
Y-parameters for a two-port passive network in a 2-by-2-by-M
array. M is the number of Y-parameters.
Frequency (Hz)
Frequencies of the Y-parameters as an M-element vector. The
order of the frequencies must correspond to the order of the
Y-parameters in Y-Parameters. All frequencies must be positive.
Interpolation method
Method used to interpolate the S-parameters, as derived from the
Y-parameters, over the range of frequencies. Interpolation can be
Cubic, Linear (default), or Spline.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
5-157
Y-Parameters Passive Network
Examples
Plotting Parameters with the Y-Parameters Passive Network
Block
The following example specifies Y-parameters [.23i, -.12i; -.12i, .23i]
and [.02-.13i, -.02+.25i; -.02+.25i, .02-.13i] at frequencies 2.0 GHz and
2.1 GHz respectively. It uses the MATLAB cat function to create the
2-by-2-by-2 Y-parameters array.
cat(3,[.23i,-.12i;-.12i,.23i],...
[.02-.13i,-.02+.25i;-.02+.25i, .02-.13i])
The plot parameters in the dialog box request a polar plane plot of the
S11 parameters in the frequency range 1.9 to 2.2 GHz.
5-158
Y-Parameters Passive Network
See Also
General Circuit Element, General Passive Network, Output Port,
S-Parameters Passive Network, Z-Parameters Passive Network
y2s (RF Toolbox)
interp1 (MATLAB)
5-159
Z-Parameters Amplifier
Purpose
Model nonlinear amplifier using its Z-parameters
Library
Amplifiers sublibrary of the Physical library
Description
The Z-Parameters Amplifier block models the nonlinear amplifier
described in the block dialog box, in terms of its frequency-dependent
Z-parameters and their frequencies. The block also takes into account
the IP3 value and the noise figure.
In the Z-Parameters field of the block dialog box, provide the
Z-parameters for each of M frequencies as a 2-by-2-by-M array. In the
Frequency field, specify the frequencies for the Z-parameters as an
M-element vector. The elements of the frequencies vector must be in
the same order as the Z-parameters. All frequencies must be positive.
For example, the following figure shows the correspondence between
the Z-parameters array and the vector of frequencies.
The Z-Parameters Amplifier block uses the RF Toolbox y2s function
to convert the Z-parameters to S-parameters, and then interpolates
the resulting S-parameters to determine their values at the modeling
frequencies. The modeling frequencies are determined by the Output
Port block. See Appendix A, “RF Blockset Algorithms” for more details.
5-160
Z-Parameters Amplifier
Dialog
Box
Z-Parameters
Z-parameters for a nonlinear amplifier in a 2-by-2-by-M array. M
is the number of Z-parameters.
Frequency (Hz)
Frequencies of the Z-parameters as an M-element vector. The
order of the frequencies must correspond to the order of the
Z-parameters in Z-Parameters. All frequencies must be positive.
Interpolation method
Method used to interpolate the S-parameters, as derived from the
Z-parameters, over the range of frequencies. Interpolation can be
Cubic, Linear (default), or Spline.
5-161
Z-Parameters Amplifier
IP3 type
Type of third-order intercept point. The value can be IIP3 (input
intercept point) or OIP3 (output intercept point).
IIP3 (dBm)
Input power intercept point as a scalar value. This field becomes
visible if you select IIP3 as the IP3 type.
OIP3 (dBm)
Output power intercept point as a scalar value. This field becomes
visible if you select OIP3 as the IP3 type.
Noise figure (dB)
Scalar ratio of the available signal-to-noise power ratio at the
input to the available signal-to-noise power ratio at the output,
(Si/Ni)/(So/No).
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
Examples
Plotting Parameters with the Z-Parameters Amplifier Block
The following example specifies Z-parameters [12.60+3.80i, 3.77-0.17i;
80.02+54.68i, 26.02+3.84i] and [15.12+3.55i, 4.14-0.92i; 92.10+23.67i,
27.59+2.71i] at frequencies 2.0 GHz and 2.1 GHz respectively. It uses
the MATLAB cat function to create the 2-by-2-by-2 Z-parameters array.
cat(3,[12.60+3.80i, 3.77-0.17i; 80.02+54.68i, 26.02+3.84i],...
[15.12+3.55i, 4.14-0.92i; 92.10+23.67i, 27.59+2.71i])
5-162
Z-Parameters Amplifier
The plot parameters in the dialog box request an X-Y plane plot of the
S11 parameters in the frequency range 1.9 to 2.2 GHz.
5-163
Z-Parameters Amplifier
See Also
General Amplifier, Output Port, S-Parameters Amplifier, Y-Parameters
Amplifier
z2s (RF Toolbox)
interp1 (MATLAB)
5-164
Z-Parameters Mixer
Purpose
Model mixer using its Z-parameters
Library
Mixer sublibrary of the Physical library
Description
The Z-Parameters Mixer block models the nonlinear mixer described in
the block dialog box in terms of its frequency-dependent Z-parameters,
their frequencies, and the reference impedance of the Z-parameters.
The block also takes phase noise into account.
The Z-parameter values all refer to the mixer input frequency.
The Z-Parameters Mixer block uses the RF Toolbox y2s function to
convert the Z-parameters to S-parameters and then interpolates the
resulting S-parameters to determine their values at the modeling
frequencies. The modeling frequencies are determined by the Output
Port block. See Appendix A, “RF Blockset Algorithms” for more details.
The RF Blockset computes the normalized reflected amplitude at the
mixer input ( Er1 ) and at the mixer output ( Er2 ) from the interpolated
S-parameters as
Er1 ( fin ) = S11 ( fin ) Ei1 ( fin ) + S12 ( fin ) Ei2 ( fout )
Er 2 ( fout ) = S21 ( fin ) Ei1 ( fin ) + S22 ( fin ) Ei2 ( fout )
where
•
fin and f out are the mixer input and output frequencies, respectively.
• Ei1 and Ei2 are the normalized incident amplitudes at the mixer
input and output, respectively.
The interpolated S21 parameter values describe the conversion gain as
a function of frequency, referred to the mixer input frequency.
5-165
Z-Parameters Mixer
Dialog
Box
Z-Parameters
Z-parameters for a nonlinear mixer in a 2-by-2-by-M array. M
is the number of Z-parameters.
5-166
Z-Parameters Mixer
Frequency (Hz)
Frequencies of the Z-parameters as an M-element vector. The
order of the frequencies must correspond to the order of the
Z-parameters in Z-Parameters. All frequencies must be positive.
The following figure shows the correspondence between the
Z-parameters array and the vector of frequencies.
Interpolation method
Method used to interpolate the S-parameters, as derived from the
Z-parameters, over the range of frequencies. Interpolation can be
Linear (default), Spline, or Cubic.
Type
Type of mixer. Choices are Downconverter (default) and
Upconverter.
LO frequency (Hz)
Local oscillator frequency. If you choose Downconverter, the RF
Blockset computes the mixer output frequency,
f out , from the
mixer input frequency, f in , and the local oscillator frequency, f lo ,
. If you choose Upconverter,
.
as
5-167
Z-Parameters Mixer
Note The mixer output frequency must be positive. This means
that if you choose a downconverting mixer,
than
fin must be greater
flo . Otherwise, an error appears.
IP3 type
Type of third-order intercept point. The value can be IIP3 (input
intercept point) or OIP3 (output intercept point).
IIP3 (dBm)
Input power intercept point as a scalar value. This field becomes
visible if you select IIP3 as the IP3 type.
OIP3 (dBm)
Output power intercept point as a scalar value. This field becomes
visible if you select OIP3 as the IP3 type.
Noise figure (dB)
Scalar ratio of the available signal-to-noise power ratio at the
input to the available signal-to-noise power ratio at the output,
(Si/Ni)/(So/No).
Phase noise frequency offset (Hz)
Vector specifying the frequency offset.
Phase noise level (dBc/Hz)
Vector specifying the phase noise level.
Note For information about plotting the mixer parameters, see
Chapter 3, “Plotting Model Data”.
See Also
5-168
General Mixer, Output Port, S-Parameters Mixer, Y-Parameters Mixer
Z-Parameters Passive Network
Purpose
Model passive network using its Z-parameters
Library
Black Box Elements sublibrary of the Physical library
Description
The Z-Parameters Passive Network block models the two-port passive
network described in the block dialog box, in terms of its Z-parameters
and their associated frequencies.
In the Z-Parameters field of the block dialog box, provide the
Z-parameters for each of M frequencies as a 2-by-2-by-M array. In the
Frequency field, specify the frequencies for the Z-parameters as an
M-element vector. The elements of the vector must be in the same order
as the Z-parameters. All frequencies must be positive. For example, the
following figure shows the correspondence between the Z-parameters
array and the vector of frequencies.
The Z-Parameters Passive Network block uses the RF Toolbox y2s
function to convert the Z-parameters to S-parameters, and then
interpolates the resulting S-parameters to determine their values at
the modeling frequencies. The modeling frequencies are determined
by the Output Port block. See Appendix A, “RF Blockset Algorithms”
for more details.
5-169
Z-Parameters Passive Network
Dialog
Box
Z-Parameters
Z-parameters for a two-port passive network in a 2-by-2-by-M
array. M is the number of Z-parameters.
Frequency (Hz)
Frequencies of the Z-parameters as an M-element vector. The
order of the frequencies must correspond to the order of the
Z-parameters in Z-Parameters. All frequencies must be positive.
Interpolation method
Method used to interpolate the S-parameters, as derived from the
Z-parameters, over the range of frequencies. Interpolation can be
Cubic, Linear (default), or Spline.
Note For information about plotting, see Chapter 3, “Plotting Model
Data”.
5-170
Z-Parameters Passive Network
Examples
Plotting Parameters with the Z-Parameters Passive Network
Block
The following example specifies Z-parameters [0.13 - 5.93i, .03-3.16i;
0.03-3.16i, .13-5.93i] and [0.27-2.86i, -.09-5.41i; -.09-5.41i, .27-2.86i] at
frequencies 2.0 GHz and 2.1 GHz respectively. It uses the MATLAB cat
function to create the 2-by-2-by-2 Z-parameters array.
cat(3,[0.13-5.93i, .03-3.16i; 0.03-3.16i, .13-5.93i],...
[0.27-2.86i,-.09-5.41i; -.09-5.41i, .27-2.86i])
The plot parameters in the dialog box request an X-Y plane plot of the
S12 parameters in the frequency range 1.9 to 2.2 GHz.
5-171
Z-Parameters Passive Network
See Also
General Circuit Element, General Passive Network, Output Port,
S-Parameters Passive Network, Y-Parameters Passive Network
z2s (RF Toolbox)
interp1 (MATLAB)
5-172
A
RF Blockset Algorithms
Simulating an RF Model (p. A-2)
Gives an overview of how the RF
Blockset simulates an RF model.
Determining the Modeling
Frequencies (p. A-3)
Describes how the RF Blockset
computes the modeling frequencies
of a physical system.
Mapping Network Parameters to
Modeling Frequencies (p. A-5)
Describes how the RF Blockset
determines the values of the
S-parameters of the physical blocks
at the modeling frequencies.
Modeling Noise in an RF System
(p. A-7)
Describes how the RF Blockset
models thermal noise in an RF
system.
Creating a Complex
Baseband-Equivalent Model
(p. A-10)
Describes how the RF Blockset uses
the frequency-domain parameters
of the RF blocks to create a
baseband-equivalent model for
time-domain simulation.
Converting to and from Simulink
Signals (p. A-15)
Explains how the Input Port and
Output Port convert Simulink
signals to and from the RF Blockset
physical modeling environment
during a simulation.
A
RF Blockset Algorithms
Simulating an RF Model
When you simulate a model that contains physical blocks, the RF Blockset
determines the modeling frequencies of the physical system using the
Input Port block parameters. The modeling frequencies are the frequencies
at which the blockset takes information from the blocks to construct the
baseband-equivalent model. Then, the RF Blockset determines the block
parameter values at those frequencies and uses the information to create a
baseband-equivalent model for time-domain simulation in Simulink.
A-2
Determining the Modeling Frequencies
Determining the Modeling Frequencies
When you simulate an RF model, the Output Port block uses Input Port block
parameters to determine the modeling frequencies f for the physical system
that is bracketed between the Input Port block and the Output Port block. f is
an N-element vector, where N is the finite impulse response filter length. The
modeling frequencies are a function of the center frequency fc and the sample
time ts. The following figure shows the Input Port block parameters that
determine the modeling frequencies.
N
fc
ts
A-3
A
RF Blockset Algorithms
fn is the nth element of the vector of modeling frequencies, f, and is given by
fn = fmin +
n −1
n = 1,..., N
ts N
where
fmin = fc −
A-4
1
2ts
Mapping Network Parameters to Modeling Frequencies
Mapping Network Parameters to Modeling Frequencies
In a physical system, each block provides network parameters at
different frequencies. These frequencies are not necessarily the modeling
frequencies for the physical system in which the block resides. To create a
baseband-equivalent model, the RF Blockset must calculate the values of the
S-parameters at the modeling frequencies.
Individual physical blocks calculate the S-parameters at the modeling
frequencies determined by the Input Port block parameters. Each block
interpolates its S-parameters to determine the S-parameters at the modeling
frequencies. If the block contains network Y- or Z-parameters, it first converts
them to S-parameters.
Specifically, the block orders the S-parameters in the ascending order of their
frequencies, fn. Then, it interpolates the S-parameters using the MATLAB
interp1 function. For example, the curve in the following diagram illustrates
the result of interpolating the S11 parameters at original frequencies f1
through f5.
Interpolated S11 parameter values
Original S11 parameter values
f1
(fmin)
f2
f4
f5
f3
(fmax)
Frequencies in ascending
order of magnitude
The Interpolation field in the individual block dialog boxes enables you to
specify the interpolation method as Cubic, Linear (default), or Spline. For
more information about these methods, see “One-Dimensional Interpolation”
and the interp1 reference page in the MATLAB documentation.
As shown in the previous diagram, each block uses the parameter values
at fmin for all modeling frequencies smaller than fmin. The block uses the
A-5
A
RF Blockset Algorithms
parameter values at fmax for all modeling frequencies greater than fmax. In
both cases, the results may not be accurate, so you need to specify network
parameter values over a range of frequencies that is wide enough to account
for the block behavior.
A-6
Modeling Noise in an RF System
Modeling Noise in an RF System
The RF Blockset physical blocks model thermal noise. The Input Port block
parameters specify whether to include noise in a simulation. When you
include noise information in your model, the RF Blockset simulates the
thermal noise of the physical system. This section explains how the RF
Blockset simulates noise from user-specified information. For information on
how to add noise to an RF model, see “Modeling Thermal Noise” on page 2-22.
In general, you can specify output-referred noise in one of three ways:
• Noise temperature — Specifies the noise in kelvin.
• Noise factor — Specifies the noise by the following equation
Noise factor = 1 +
Noise temperature
290
• Noise figure — Specifies the noise in decibels relative to the standard
reference noise temperature of 290 K. In terms of noise factor,
Noise figure = 10log(Noise factor)
These three specifications are equivalent, since you can compute each one
from any of the others.
For RF Blockset physical amplifier and mixer blocks, you can specify noise
using frequency-independent noise figure values. The General Amplifier
and General Mixer blocks also provide the option to specify noise as
frequency-dependent noise figure or as spot noise data.
For other RF blocks, such as transmission lines and filters, noise is only
generated by the resistors in the network. The RF Blockset calculates this
noise from basic resistor equations, so there are no noise parameters on the
block dialog boxes.
When you run the simulation, the RF Blockset first computes the noise figure
values at the modeling frequencies and then uses the noise figure information
to calculate the output noise power.
A-7
A
RF Blockset Algorithms
This section contains the following topics:
• “Calculating Noise Figure at Modeling Frequencies” on page A-8
• “Calculating Output Noise Power” on page A-9
Calculating Noise Figure at Modeling Frequencies
To include noise information in a simulation, the RF Blockset must compute
the noise figure values at the modeling frequencies.
If you specify the noise figure value directly, or if the blockset computes the
noise figure value from the block resistance, the RF Blockset uses this value
for the noise figure value at each of the modeling frequencies.
If you specify spot noise data using a Touchstone or AMP data file, the RF
Blockset computes frequency-dependent noise figure information from the
data in the file. It takes the minimum noise figure, NFmin, equivalent noise
resistance, Rn, and optimal source admittance, Yopt, values in the file and
interpolates to find the values at the modeling frequencies. Then, it uses the
following equation to calculate the noise correlation matrix, CA.
CA
⎡
Rn
⎢
= 2kT ⎢
⎢ NFmin − 1 − R Y
n opt
⎢⎣
2
NFmin − 1
⎤
− Rn Yopt∗ ⎥
2
⎥
2
⎥
Rn Yopt
⎥⎦
In the above equation, k is Boltzmann’s constant and T is the noise
temperature in kelvin. The RF Blockset then calculates the noise factor, F,
from the noise correlation matrix as follows:
F =1+
z+ C A z
2kT Re {ZS }
⎡ 1 ⎤
z = ⎢ *⎥
⎢⎣ ZS ⎥⎦
In the two preceding equations, ZS is the nominal impedance, which is 50
ohms, and z+ is the Hermitian conjugation of z.
A-8
Modeling Noise in an RF System
The RF Blockset obtains the noise figure, NF, from the noise factor:
NF = 10 log( F )
For more information about these calculation techniques, see the following
article:
Hillbrand, H. and P.H. Russer, “An Efficient Method for Computer Aided
Noise Analysis of Linear Amplifier Networks,” IEEE Transactions on Circuits
and Systems, Vol. CAS-23, Number 4, pp. 235-238, 1976.
Calculating Output Noise Power
The RF Blockset uses noise power to determine the amplitude of the noise
that it adds to the system using a Gaussian distributed pseudorandom
number generator. It uses both the noise temperature and the modeling
bandwidth to calculate the noise power:
Noise power = kTB
Here, k is Boltzmann’s constant, which is 1.38e-23 J/K, T is the noise
temperature in kelvin and B is the bandwidth in hertz.
The RF Blockset computes noise temperature from the specified or calculated
noise figure values, and it computes the modeling bandwidth from the model’s
sample time and center frequency.
For more information, see the rfdata.noise and rfdata.nf reference pages.
A-9
A
RF Blockset Algorithms
Creating a Complex Baseband-Equivalent Model
The RF Blockset simulates the physical system in the time domain using
a baseband-equivalent model that it creates from the frequency-domain
parameters of the physical blocks.
This section contains the following topics:
• “Baseband-Equivalent Modeling” on page A-10
• “Simulation Efficiency of a Complex Baseband-Equivalent Model” on page
A-13
Baseband-Equivalent Modeling
To create a complex baseband-equivalent model in the time domain based on
the network parameters of the physical system, the RF Blockset performs a
mathematical transformation that consists of the following three steps:
1 “Calculating the Passband Transfer Function” on page A-10
2 “Calculating the Baseband Transfer Function” on page A-12
3 “Calculating the Baseband-Equivalent Impulse Response” on page A-13
Calculating the Passband Transfer Function
The RF Blockset calculates the passband transfer function from the physical
block parameters at the modeling frequencies.
Note To learn how the RF Blockset uses the specified network parameters to
compute the network parameters at the modeling frequencies, see “Mapping
Network Parameters to Modeling Frequencies” on page A-5.
The transfer function is defined as
H( f ) =
A-10
VL ( f )
VS ( f )
Creating a Complex Baseband-Equivalent Model
where VS and VL are the source and load voltages shown in the following
figure, and f represents the modeling frequencies.
Zs
+
Vs
-
+
Vin
-
+
Physical
Subsystem
Z
L
VL
-
More specifically,
H( f ) =
S21 * (1 + Γ l ) * (1 − Γ s )
2 * (1 − S22 * Γ l ) (1 − Γin * Γ s )
where
Γl =
Zl − Zo
Zl + Zo
Γs =
Zs − Zo
Zs + Zo
⎛
⎞
Γl
Γin = S11 + ⎜⎜ S12 * S21 *
⎟
(1 − S22 * Γ l ) ⎟⎠
⎝
and
• ZS is the source impedance.
• ZL is the load impedance.
• Sij are the S-parameters of a two-port network.
A-11
A
RF Blockset Algorithms
The passband transfer function is shown in the following figure:
Specify these parameters in the Input Port dialog box:
Passband Spectrum of a Modulated RF Carrier
Finite impulse response filter length = N
Center frequency = fc
Sample time = ts
Magnitude
1/(ts*N)
Index = n
Frequency
fmin
Index = 1
fc
fn
1/ts
fmax
Index = N
Calculating the Baseband Transfer Function
The RF Blockset calculates the baseband transfer function, Hbaseband ( f ) ,
by translating the passband transfer function to its equivalent baseband
transfer function:
Hbaseband ( f ) = H passband ( f + fc )
where fc is the specified center frequency.
The resulting baseband-equivalent spectrum is centered at zero, so the
RF Blockset can simulate the system using a much larger time step than
Simulink can use for the same system. For information on why this
translation allows for a larger time step, see “Simulation Efficiency of a
Complex Baseband-Equivalent Model” on page A-13.
A-12
Creating a Complex Baseband-Equivalent Model
The baseband transfer function is shown in the following figure:
Baseband-Equivalent Spectrum
Magnitude
Centered at zero
1/2ts
-1/2ts
Frequency
1/ts
Calculating the Baseband-Equivalent Impulse Response
The RF Blockset calculates the baseband-equivalent impulse response by
calculating the inverse FFT of the baseband transfer function. For faster
simulation, the block calculates the IFFT using the next power of 2 greater
than the specified finite impulse response filter length. Then, it truncates the
impulse response to a length equal to the filter length specified.
Simulation Efficiency of a Complex
Baseband-Equivalent Model
The baseband-equivalent modeling technique improves simulation speed by
allowing the simulator to take larger time steps. To simulate a system in the
time domain, Simulink would require a step size of:
tstep =
1
2 fmax
A-13
A
RF Blockset Algorithms
Using the baseband-equivalent model of the same system, whose spectrum
has been shifted down by fc, allows for a much larger time step of:
tstep =
A-14
1
2( fmax − fc )
=
1
fmax − fmin
Converting to and from Simulink Signals
Converting to and from Simulink Signals
When you simulate an RF model, the RF Blockset must convert the
mathematical Simulink signals to and from the RF Blockset physical modeling
environment. To perform this conversion, the RF Blockset interprets the
Simulink signal that enters the Input Port block, Sin, as the voltage VS across
the source impedance ZS. This process is shown in the following figure.
Simulink
signal
Vs
Zs
+
Vin
-
Sin=Vs
Input Port Block
Zin
RF System Parameters
Z
L
+
VL
-
Simulink
signal
Sout = V L
Output Port Block
The RF Blockset interprets the output Simulink signal as the voltage VL over
the load impedance ZL. You specify the source and load impedances in the
Input Port and Output Port dialog boxes, respectively.
The RF Blockset interpretation of the input Simulink signal as the source
voltage, VS, produces different results than the interpretation that the
input Simulink signal is the input voltage, Vin. When the source and load
A-15
A
RF Blockset Algorithms
impedances are the same, the former interpretation produces 6 dB of loss
compared to the latter. You can see how this loss arises by analyzing the
equivalent circuit model for each interpretation when there are no blocks
between the Input Port and Output Port blocks.
The following figure shows the equivalent circuit model when the input
Simulink signal, Sin, is taken to be the input voltage shown in the previous
diagram.
+
+
Sin
VL
R
-
-
The load power is
PL =
2
VL2 Sin
=
R
R
In decibels, the load power is
⎛ S2 ⎞
10 log ( PL ) = 10 log ⎜ in ⎟
⎜ R ⎟
⎝
⎠
(A-1)
The following figure shows the equivalent circuit model when the input
Simulink signal, Sin, is taken to be the source voltage shown in the previous
diagram.
R
+
Sin
+
R
-
The load power is
A-16
VL
-
Converting to and from Simulink Signals
PL =
VL2
R
=
(
Sin
2
)
2
R
In decibels, the load power is
⎛ S2 ⎞
⎛ S2 ⎞
10 log ( PL ) = 10 log ⎜ in ⎟ = 10 log ⎜ in ⎟ − 6.02
⎜ 4R ⎟
⎜ R ⎟
⎝
⎠
⎝
⎠
(A-2)
This load power is 6 dB less than the load power computed in Equation A-1.
A-17
A
A-18
RF Blockset Algorithms
B
Examples
Use this list to find examples in the documentation.
B
Examples
Examples
“Example — Modeling an LC Bandpass Filter” on page 1-12
“Example — Importing a Touchstone Data File into an RF Model” on
page 2-8
“Example — Importing a Bandstop Filter into an RF Model” on page 2-15
“Example — Plotting Component Data on a Z Smith Chart” on page 3-15
“Example — Creating and Modifying Subsystem Plots” on page 3-22
B-2
Index
A
Index
active noise
General Amplifier block 5-35
General Mixer block 5-44
adding
noise 2-23
adding physical and mathematical blocks 2-2
algorithm
simulation A-2
amplifier
modeling from file data 5-38
modeling from rfdata object 5-35
Amplifier block 5-2
effects 5-5
modeling nonlinearity 5-2
methods 5-7
sample time comparison 5-11
thermal noise simulation 5-10
See also General Amplifier block
amplifier blocks
mathematical 4-2
physical 4-4
B
Bandpass RF Filter block 5-16
sample time comparison 5-17
Bandstop RF Filter block 5-20
sample time comparison 5-21
baseband-equivalent model
creating A-10
simulation efficiency A-13
baseband-equivalent time domain
modeling 5-98
linear subsystem 5-98
nonlinear subsystem 5-102
Bessel filter design
Bandpass RF Filter block 5-16
Bandstop RF Filter block 5-20
Highpass RF Filter block 5-52
Lowpass RF Filter block 5-86
black box elements blocks 4-4
block parameters
setting 2-6
blocks
connecting 2-2
mathematical 4-2
physical 4-3
Butterworth filter design
Bandpass RF Filter block 5-16
Bandstop RF Filter block 5-20
Highpass RF Filter block 5-52
Lowpass RF Filter block 5-86
C
Chebyshev I filter design
Bandpass RF Filter block 5-16
Bandstop RF Filter block 5-20
Highpass RF Filter block 5-52
Lowpass RF Filter block 5-86
Chebyshev II filter design
Bandpass RF Filter block 5-16
Bandstop RF Filter block 5-20
Highpass RF Filter block 5-52
Lowpass RF Filter block 5-86
circuit element
modeling from rfckt object 5-42
circuit objects
importing 2-14
Coaxial Transmission Line block 5-24
shunt and series stubs 5-25
stubless 5-24
composite data plots 3-5
connecting blocks
RF Physical blocks to Simulink 2-2
Simulink to RF Physical blocks 2-2
connector blocks 4-5
Input Port 5-56
Output Port 5-98
Index-1
Index
conversion
Simulink signal to RF signal A-15
Coplanar Waveguide Transmission Line
block 5-29
shunt and series stubs 5-30
stubless 5-29
D
data consistency
General Amplifier block 5-35
data files
importing 2-7
demos
in Help browser 1-4
E
Elliptic filter design
Bandpass RF Filter block 5-16
Bandstop RF Filter block 5-20
Highpass RF Filter block 5-52
Lowpass RF Filter block 5-86
example
creating and modifying plots 3-22
importing circuit objects 2-15
importing Touchstone file 2-8
F
filter blocks
mathematical 4-2
physical 4-3
filter design
physical blocks
LC Lowpass Tee block 5-83
filter design mathematical blocks
Bandpass RF Filter block 5-16
Bandstop RF Filter block 5-20
Highpass RF Filter block 5-52
Lowpass RF Filter block 5-86
Index-2
filter design physical blocks
LC Bandpass Pi block 5-59
LC Bandpass Tee block 5-65
LC Bandstop Pi block 5-68
LC Bandstop Tee block 5-71
LC Highpass Pi block 5-74
LC Highpass Tee block 5-77
LC Lowpass Pi block 5-80
format
changing in plot 3-20
frequency range
changing in plot 3-20
G
General Amplifier block 5-35
active noise 5-35
generating from file data 5-38
nonlinearity 5-35
See also Amplifier block
General Circuit Element block 5-41
generating from rfckt object 5-42
General Mixer block 5-44
active noise 5-44
phase noise 5-45
See also Mixer block
General Passive Network block 5-49
generating from file data 5-50
Ghorbani model 5-9
H
Help browser
demos 1-4
Highpass RF Filter block 5-52
sample time comparison 5-53
I
importing
circuit objects 2-14
Index
data files 2-7
Input Port block 5-56
parameter input for physical
subsystem 5-56
sample time comparison 5-56
See also Output Port block
interpolation
network parameters A-5
L
ladder filter blocks 4-3
ladder filters
example to filter Gaussian noise 5-61
LC Bandpass Pi block 5-59
example to filter Gaussian noise 5-61
LC Bandpass Tee block 5-65
LC Bandstop Pi block 5-68
LC Bandstop Tee block 5-71
LC Highpass Pi block 5-74
LC Highpass Tee block 5-77
LC Lowpass Pi block 5-80
LC Lowpass Tee block 5-83
libraries
RF physical and mathematical 1-6
library
RF mathematical 1-9
RF physical 1-7
link budget plots 3-7
Lowpass RF Filter block 5-86
sample time comparison 5-87
M
mathematical and physical models
connecting 2-2
mathematical modeling blocks 1-9
Microstrip Transmission Line block 5-90
shunt and series stubs 5-91
stubless 5-90
Mixer block 5-95
sample time comparison 5-96
See also General Mixer block
mixer blocks
mathematical 4-2
physical 4-5
model
adding RF components to 2-2
modeling
amplifier from file data 5-38
amplifier from rfdata object 5-35
baseband-equivalent time domain 5-98
circuit element from rfckt object 5-42
passive network from file data 5-50
modeling frequencies
calculating A-3
calculating noise A-8
S-parameter interpolation A-5
models
physical and mathematical blocks 1-6
N
network parameters
adding to a plot 3-20
interpolation at modeling frequencies A-5
noise
active
General Amplifier block 5-35
General Mixer block 5-44
adding 2-23
calculating at modeling frequencies A-8
phase
General Mixer block 5-45
plotting 2-24
specifying mixer and amplifier 2-22
noise output power
calculating A-9
noise simulation A-7
nonlinearity
Index-3
Index
Amplifier block 5-2
General Amplifier block 5-35
O
opening
block libraries 1-6
Output Port block 5-98
baseband-equivalent time domain
modeling 5-98
plotting RF subsystem parameters 5-106
See also Input Port block
output power
calculating noise A-9
P
Parallel-Plate Transmission Line block 5-107
shunt and series stubs 5-108
stubless 5-107
parameter input
to physical subsystem 5-56
parameters
adding to a plot 3-20
passive network
modeling from file data 5-50
phase noise
General Mixer block 5-45
physical and mathematical models
connecting blocks 2-2
physical modeling blocks 1-7
physical subsystem
parameter input for 5-56
plot types
modifying 3-20
plots
budget 3-7
changing format of 3-20
changing frequency range of 3-20
composite 3-5
Index-4
creating 3-9
displaying legend 3-15
example of creating and modifying 3-22
format 3-4
modifying 3-20
noise 2-24
RF subsystem parameters 5-106
Smith chart example 3-15
types of 3-3
updating 3-19
using block parameters to specify 3-9
X-Y plane 3-7
product demos 1-4
R
Rapp model 5-10
RF block libraries
Mathematical 4-2
Physical 4-3
RF Blockset
required and related products 1-3
RF Blockset libraries 1-6
how to open 1-6
RF models
connecting blocks 2-2
rfckt object
modeling general circuit element 5-41
rfdata object
modeling nonlinear amplifier 5-35
RLCG Transmission Line block 5-112
shunt and series stubs 5-113
stubless 5-112
S
S-Parameters Amplifier block 5-117
S-Parameters Mixer block 5-122
S-Parameters Passive Network block 5-126
Saleh model 5-8
Index
Series RLC block 5-131
setting
block parameters 2-6
Shunt RLC block 5-134
simulation
noise A-7
simulation algorithm
overview A-2
Simulink signal
converting to and from A-15
Smith chart
example 3-15
specifying
mixer and amplifier thermal noise 2-22
stubless transmission lines
Coaxial Transmission Line block 5-24
Coplanar Waveguide Transmission Line
block 5-29
Microstrip Transmission Line block 5-90
Parallel-Plate Transmission Line
block 5-107
RLCG Transmission Line block 5-112
Transmission Line block 5-137
Two-Wire Transmission Line block 5-142
stubs (shunt and series)
Coaxial Transmission Line block 5-25
Coplanar Waveguide Transmission Line
block 5-30
Microstrip Transmission Line block 5-91
Parallel-Plate Transmission Line
block 5-108
RLCG Transmission Line block 5-113
Transmission Line block 5-138
Two-Wire Transmission Line block 5-143
specifying mixer and amplifier 2-22
time-domain modeling
baseband-equivalent 5-98
Touchstone file
importing 2-8
Transmission Line block 5-137
shunt and series stubs 5-138
stubless 5-137
transmission line blocks 4-3
Two-Wire Transmission Line block 5-142
shunt and series stubs 5-143
stubless 5-142
V
viewing
demos 1-4
W
workflow
RF Blockset 1-10
workflow example
RF Blockset 1-12
Y
Y-Parameters Amplifier block 5-147
Y-Parameters Mixer block 5-152
Y-Parameters Passive Network block 5-156
Z
Z-Parameters Amplifier block 5-160
Z-Parameters Mixer block 5-165
Z-Parameters Passive Network block 5-169
T
thermal noise
Index-5
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