X-parameters are a generalization of
S-parameters
Scattering parameters or S-parameters (the elements of a scattering matrix or S-matrix) describe the electrical behavior of linear electrical networks when undergoing various steady state stimuli by electrical signals.
The parameters are useful f ...
and are used for characterizing the amplitudes and relative phase of harmonics generated by nonlinear components under large input power levels. X-parameters are also referred to as the parameters of the Poly-Harmonic Distortion (PHD) nonlinear behavioral model.
Description
X-parameters represent a new category of
nonlinear
In mathematics and science, a nonlinear system is a system in which the change of the output is not proportional to the change of the input. Nonlinear problems are of interest to engineers, biologists, physicists, mathematicians, and many other ...
network parameters for high-frequency design (Nonlinear vector network analyzers are sometimes called large signal network analyzers.)
X-parameters are applicable to both
large-signal
Large-signal modeling is a common analysis method used in electronic engineering to describe nonlinear devices in terms of the underlying nonlinear equations.
In circuits containing nonlinear elements such as transistors, diodes, and vacuum tubes ...
and
small-signal
Small-signal modeling is a common analysis technique in electronics engineering used to approximate the behavior of electronic circuits containing nonlinear devices with linear equations. It is applicable to electronic circuits in which the AC s ...
conditions, for linear and nonlinear components. They are an extension of
S-parameters
Scattering parameters or S-parameters (the elements of a scattering matrix or S-matrix) describe the electrical behavior of linear electrical networks when undergoing various steady state stimuli by electrical signals.
The parameters are useful f ...
meaning that, in the limit of a small signal, X-parameters reduce to S-parameters.
They help overcome a key challenge in
RF engineering
Radio-frequency (RF) engineering is a subset of electronic engineering involving the application of transmission line, waveguide, antenna and electromagnetic field principles to the design and application of devices that produce or use signals ...
, namely that nonlinear
impedance differences,
harmonic mixing
Harmonic mixing or key mixing (also referred to as mixing in key) is a DJ's continuous mix between two pre-recorded tracks that are most often either in the same key, or their keys are relative or in a subdominant or dominant relationship ...
, and nonlinear reflection effects occur when components are cascaded under large signal operating conditions. This means that there is a nonlinear and as such non-trivial relationship between the properties of the individual cascaded components and the composite properties of the resulting cascade. This situation is unlike that at
DC, where one can simply add the values of
resistor
A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias activ ...
s connected in series. X-parameters help solve this cascading problem: if the X-parameters of a set of components are measured individually, the X-parameters (and hence the non-linear transfer function) can be calculated of any cascade made from them. Calculations based on X-parameters are usually performed within a harmonic balance simulator environment.
Development
X-parameters were developed and introduced by
Keysight Technologies
Keysight Technologies, or Keysight, is an American company that manufactures electronics test and measurement equipment and software. The name is a blend of ''key'' and ''insight''. The company was formed as a spin-off of Agilent Technologies, wh ...
as functionality included i
N5242A Nonlinear Vector Network Analyzer and the W2200
Advanced Design System
Advanced Design System (ADS) is an electronic design automation software system produced by PathWave Design, a division of Keysight Technologies. It provides an integrated design environment to designers of RF electronic products such as mob ...
in 2008. N5242A is a Keysight product that were formerly part of Agilent.
X-parameters are the parameters of the polyharmonic distortion modeling work of Dr. Jan Verspecht
[ (PDF, 85 KB)][ (PDF, 2.4MB)] and Dr. David E. Root.
[
]
See also
*Two-port network
A two-port network (a kind of four-terminal network or quadripole) is an electrical network (circuit) or device with two ''pairs'' of terminals to connect to external circuits. Two terminals constitute a port if the currents applied to them satis ...
Notes
External links
Fundamentally Changing Nonlinear Microwave Design
by David Vye Editor, Microwave Journal Vol. 53 No. 3 March 2010 Page 22]
former location
{{DEFAULTSORT:X-Parameters
Electrical parameters
Two-port networks
Transfer functions