## Documentation Center |

You can now use the deembedsparams function to de-embed 2N-port fixture effects from 2N-port measurements. It supports both three-dimensional S-parameters data and S-parameter objects.

You can use the rfwrite function to write Touchstone files from three-dimensional network parameter data or any network parameter object (S-parameters, Y-parameters, Z-parameters, ABCD-parameters, etc.)

The rationalfit function now fits a rational model to S-parameter data at least six times faster than previous releases. This responsiveness improves both RF Toolbox™ command-line behavior and SimRF™ simulation of S-parameter blocks.

In R2013b, the following new functions are available:

resistor, capacitor, inductor, and circuit — Use the basic building functions of an RF circuit to construct RLC networks.

add — Insert basic RF elements to a circuit.

clone — Duplicate any existing RF elements or circuits.

setports — Define node pairs as ports of a circuit.

setterminals — Map the nodes of a circuit to terminals.

The sparameters function now includes added functionality that you can use to calculate the S-parameters of RLC networks.

This release introduces additional pole-searching optimizations
to the `rationalfit` function
algorithm. Models that the function returns in this release tend to
have fewer poles than those in previous releases.

To constrain the function results across releases and machine architectures, explicitly specify optional parameters such as error tolerance and number of poles when you call the function. Given a data set and corresponding frequencies, the function attempts to calculate a rational function approximation to within a given specification. However, the exact model that the function returns can differ between releases and machines, as the algorithm improves.

New network parameter objects and functions are available, with support for:

Reading Touchstone files

Converting network parameters

Plotting network parameters

Additionally, some functions have been updated to support the new interface. For more information, see RF Network Parameter Objects.

The `rationalfit` function
now supports using name-value pairs for optional input arguments.
Name-value pair arguments can be specified in any order and improve
readability of code.

S-parameter conversion functions have been enhanced to support
larger data sets. The following functions now support conversion between
parameter sets of 2*N*-port networks.

The `s2smm` function
now supports mixed-mode conversions for *N*-port
devices.

The following mixed-mode S-parameter functions now support mixed-mode
conversions for 2*N*-port devices:

Two new signal-integrity demos are available in this version.

The Bandpass Filter ResponseBandpass Filter Response demo describes a procedure for designing and analyzing a simple bandpass filter using

`rfckt`objects.The MOS Interconnect and CrosstalkMOS Interconnect and Crosstalk demo reproduces Pillage and Rohrer's classic result from "Waveform Evaluation for Timing Analysis".

The `rationalfit` function
has improved robustness, speed, and accuracy in this version.

The `OpenIF` object
supports a new partial workflow for multiband transmitter or receiver
design. Use these objects to analyze intermediate frequencies (IFs)
that do not produce interference (spurs) in operating bands.

The `rationalfit` function
has improved robustness, speed, and accuracy in this version.

Some default values of `rationalfit` have changed.
For more information, see the function reference page.

For R2011b, error and warning messages identifiers have changed in RF Toolbox software.

If you have scripts or functions that use message identifiers that changed, you must update the code to use the new identifiers. Typically, message identifiers are used to turn off specific warning messages, or in code that uses a try/catch statement and performs an action based on a specific error identifier.

For example, the `rf:rfckt:seriesrlc:setpositive:NotAPositive` identifier
has changed to `rf:rfbase:rfbase:setpositive:NotAPositive`.
If your code checks for `rf:rfckt:seriesrlc:setpositive:NotAPositive`,
you must update it to check for `rf:rfbase:rfbase:setpositive:NotAPositive` instead.

To determine the identifier for a warning, run the following command just after you see the warning:

[MSG,MSGID] = lastwarn;

This command saves the message identifier to the variable `MSGID`.

To determine the identifier for an error, run the following command just after you see the error:

exception = MException.last; MSGID = exception.identifier;

An improved algorithm for the `rationalfit` function
fits an accurate rational model to passive S-parameter data in less
time than in previous versions. In addition, a new parameter specifies
the number of iterations `rationalfit` attempts
at each value for the number of poles.

Default behavior for some parameters have changed:

The number-of-poles argument

`npoles`defaults to a minimum value of`0`in version 2.8, instead of`4`, as in previous versions.`rationalfit`does not display a wait bar by default in this version. A new`showwaitbar`parameter allows you to specify whether`rationalfit`displays a wait bar.

For more information on using this function, see the `rationalfit` reference
page.

RF Toolbox version 2.8 extends the Plots and Charts methods to include:

Support for third-order intercept point and transducer power gain parameters,

`IIP3`and`Gt`.A new method,

`table`, for visualizing network data in the Variable Editor.

The `makepassive` function
creates passive S-Parameters from any S-parameter array. Use this
function to enforce strict numerical passivity on an array of S-parameters
that represents a passive device.

The Modeling a High-Speed Backplane (Part 3: 4-Port S-Parameters to Differential TDR and TDT)Modeling a High-Speed Backplane (Part 3: 4-Port S-Parameters to Differential TDR and TDT) demo shows how to perform time-domain reflectometry (TDR) and time-domain transmission (TDT) analysis on network data.

The `ispassive` function
checks the passivity of N-port S-parameter matrices.

The `s2tf` function
can now calculate the power-wave gain of 2-port S-parameters. Calculation
in terms of voltage is still the default option.

There are two new functions for converting between 4N-port single-ended S-parameter matrices and 2N-port mixed-mode S-parameter matrices:

The

`s2smm`function lets you convert 4N-port single-ended S-parameters to 2N-port mixed-mode S-parameters. You can view the 2N-port output data to see interactions, such as crosstalk, that are not apparent in the single-ended data. This lets you easily select the ports of interest for further analysis.The

`smm2s`function lets you convert 2N-port mixed-mode S-parameters to 4N-port single-ended S-parameters.

The following objects now provide a more realistic model for dielectric loss:

To specify dielectric loss, you use a new property, `LossTangent`.
This property replaces the `SigmaDiel` parameter.

Your existing objects with a nonzero value for the `SigmaDiel` parameter
no longer model dielectric loss. Instead, the objects issue a warning
message and use the default value of zero for the `LossTangent` property
when you use the `analyze` method.

Two new demos show how to design broadband impedance matching networks for RF components:

Designing Broadband Matching Networks (Part 1: Antenna)Designing Broadband Matching Networks (Part 1: Antenna) shows how to design a matching network for an antenna.

Designing Broadband Matching Networks (Part 2: Amplifier)Designing Broadband Matching Networks (Part 2: Amplifier) shows how to design a matching network for an amplifier.

You can now use the `cascadesparams` function
to cascade the S-parameters of an arbitrary number of N-port devices
to form a network. The function lets you specify how to connect the
ports of each N-port device to the ports of the subsequent N-port
device in the cascade. For more information about the function, see
the `cascadesparams` reference
page.

The `plotyy` method now uses a more intuitive
approach when determining how to plot the specified parameters if
you do not specify the plot format. For more information about the
function, see the `plotyy` reference
page.

Use the new `z2gamma` function
to convert impedance values to reflection coefficients.

A new demo, Writing
a Touchstone FileWriting
a Touchstone File, shows how to write `rfckt` object
data to an industry-standard Touchstone data file.

Modeling
a High-Speed Backplane (Part 2: 4-Port S-Parameters to a Rational
Function Model)Modeling
a High-Speed Backplane (Part 2: 4-Port S-Parameters to a Rational
Function Model) now uses the new Communications
Toolbox™ eye diagram scope, `commscope.eyediagram`,
to plot the eye diagram.

Use the new `snp2smp` function
to convert N-port S-parameter data and termination impedances to M-port
S-parameters.

Use the new `circle` method
to place circles on a Smith^{®} Chart
to depict stability regions and display constant gain, noise figure,
reflection, and immitance circles.

Use the new `powergain` function
to compute various power gains of a 2-port network.

The `smith` method
now lets you plot the network parameters of devices with more than
two ports on a Smith Chart.

Modeling a High-Speed Backplane (Part 1: Measured 16-Port S-Parameters to 4-Port S-Parameters)Modeling a High-Speed Backplane (Part 1: Measured 16-Port S-Parameters to 4-Port S-Parameters) is the new first part of a four-part demo on "Modeling a High-Speed Backplane." The new demo shows how to extract 4-port S-parameter data from 16-port S-parameter data. The original three parts of the demo are now parts 2, 3, and 4.

The following demos replace the "Designing Impedance
Matching Networks" and "Placing Circles on a Smith Chart" demos, respectively,
and show how to use the new `circle` method:

Designing Matching Networks (Part 1: Networks with an LNA and Lumped Elements)Designing Matching Networks (Part 1: Networks with an LNA and Lumped Elements) uses the available gain design technique to design a low-noise amplifier for a wireless communication system.

Designing Matching Networks (Part 2: Single Stub Transmission Lines)Designing Matching Networks (Part 2: Single Stub Transmission Lines) shows how to design input and output matching networks for an amplifier.

The `rfckt.amplifier` and `rfckt.mixer` objects
now let you import system-level verification models of amplifiers
and mixers, respectively, using data from Agilent^{®} P2D and S2D
files.

Use P2D files to specify the following data for multiple operating conditions, such as temperature and bias values:

Small-signal network parameters

Power-dependent network parameters

Noise data

Intermodulation tables

Use S2D files to specify the following data for multiple operating conditions:

Small-signal network parameters

Gain compression (1 dB)

Third-order intercept point (IP3)

Power-dependent S

_{21}parametersNoise data

Intermodulation tables

You can import an intermodulation table into an `rfckt.mixer` object.
The object's `plot` method
has a new option for plotting mixer spur data.

Use the new `timeresp` method
of the `rfmodel.rational` object
to compute the time response of an `rfmodel` object
to a specified input signal. Use this method rather than computing
impulse response with the `impulse` method and
then convolving that response with the input signal because the `timeresp` method
generally gives a more accurate output signal for a given input signal.

Four new plotting methods provide additional plotting options:

Use the

`plotyy`method of the`rfckt`class to create a plot that contains RF circuit object data on both the left and right Y-axes.Use the

`loglog`method of the`rfckt`class to plot RF circuit object data on a log-log scale.Use the

`semilogx`method of the`rfckt`class to plot RF circuit object data using a logarithmic scale for the X-axis.Use the

`semilogy`method of the`rfckt`class to plot RF circuit object data using a logarithmic scale for the Y-axis.

Use the new `gamma2z` function
to compute input impedance from a reflection coefficient.

Tab completion is now available in the MATLAB^{®} command window
for all functions and methods. For more information on tab completion,
see the MATLAB documentation.

Data tips are now available for any RF plot. For more information on data tips, see Data Cursor — Displaying Data Values Interactively in the MATLAB documentation.

Visualizing Mixer SpursVisualizing Mixer Spurs shows how to use the toolbox to perform mixer spur analysis using data from an intermodulation table and then plot the output power spectrum of the desired signal and the undesired spurs.

Modeling
a High-Speed Backplane (Part 1: Measured 4-Port S-Parameters to a
Rational Function Model)Modeling
a High-Speed Backplane (Part 1: Measured 4-Port S-Parameters to a
Rational Function Model) now uses the `timeresp` method
to compute the time-domain response of a system characterized by measured
data.

Modeling a High-Speed
Backplane (Part 2: Rational Function Model to Simulink Model)Modeling a High-Speed
Backplane (Part 2: Rational Function Model to Simulink Model) now
includes code that you can use to generate a Simulink^{®} model for
any `rfmodel.rational` object.

Use the `s2tf` function
to convert 2-port scattering parameters into a transfer function that
represents the normalized voltage gain of a 2-port network.

Use objects from the `rfmodel` class to represent
components and networks with mathematical equations. The `rfmodel.rational` object
stores a rational function model of a component or network.

Use the `rationalfit` function
to fit a rational function to passive data that represents an RF component
or network and then store the result in an `rfmodel.rational` object.
This type of model is useful to signal integrity engineers, whose
goal is to reliably connect high-speed semiconductor devices with,
for example, multi-Gbit/s serial data streams across backplanes and
printed circuit boards.

Use the `writeva` method
of the `rfmodel` class to export a description
of an RF component or network for use in a time-domain circuit simulator.

"Modeling a High-Speed Backplane (Part 1: Measured 4-Port S-Parameters to a Rational Function Model)" shows how to use the toolbox to model a differential high-speed backplane using rational functions.

"Modeling a High-Speed Backplane (Part 2: Rational Function Model to a Verilog-A Module)" shows how to use toolbox functions to generate a Verilog-A module that models the high-level behavior of a high-speed backplane.

"Modeling a Differential High-Speed Backplane in Simulink" shows how to use Simulink to simulate a differential high-speed backplane.

Use the `s2scc` function
to convert 4-port, single-ended S-parameters to 2-port, common mode
S-parameters.

Use the `s2scd` function
to convert 4-port, single-ended S-parameters to 2-port, cross mode
S-parameters.

Use the `s2sdc` function
to convert 4-port, single-ended S-parameters to 2-port, cross mode
S-parameters.

Use the `s2sdd` function
to convert 4-port, single-ended S-parameters to 2-port, differential
mode S-parameters.

Use the `extract` function
to extract specified network parameters from a circuit or data object
and return the result in an array.

The new `Freq` property of the circuit object, `rfckt.txline`,
is a vector of positive frequencies at which the parameter values
are known.

The `Loss`, `PV`, and `ZO` properties
of the circuit object, `rfckt.txline`, can now be
vectors of line loss, phase velocity, and characteristic impedance
values that correspond to the frequencies specified in the `Freq` property.

The new `IntpType` property of the circuit
object, `rfckt.txline`, is the interpolation method
used to calculate the parameter values between the known frequencies.

In earlier versions, a plot figure would appear in a separate
window after clicking the **Plot** button. In this
version, plot figures are integrated into the GUI itself.

These objects can be used to store rfdata such as network parameters, noise figure, power, IP3, and spot noise.

Use `rfckt.delay` to
model delay lines, `rfckt.hybridg` to
model hybrid G connected networks, and `rfckt.passive` to
model RF passive networks.

The new `write` method allows saving of RF
network data into files for all `rfckt` objects.

The new methods, `read` and `restore`,
read and restore data for `rfckt.datafile`, `rfckt.amplifier`,
and `rfckt.mixer`.

The `analyze` method now takes three additional
optional inputs for the load, source, and reference impedances.

Release | Features or Changes with Compatibility Considerations |
---|---|

R2014a | None |

R2013b | None |

R2013a | Improved rationalfit function |

R2012b | None |

R2012a | None |

R2011b | |

R2011a | None |

R2010b | Enhanced Rational Function Modeling |

R2010a | None |

R2009b | None |

R2009a | Enhanced Dielectric Loss Model in Three Transmission Line Objects |

R2008b | None |

R2008a | None |

R2007b | None |

R2007a | None |

R2006b | None |

R2006a | None |

R14SP3 | None |

R14SP2 | None |

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© 1994-2014 The MathWorks, Inc.

© 1994-2014 The MathWorks, Inc.