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 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 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, namely that nonlinear
impedance differences,
harmonic mixing, 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 active el ...
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 as functionality included i
N5242A Nonlinear Vector Network Analyzer and the W2200
Advanced Design System 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
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