RF Amplifier
Use the rfckt.amplifier
object to represent RF amplifiers
that are characterized by network parameters, noise data, and nonlinearity data
Use the read
object function to read the amplifier
data from a data file in one of the following formats:
Touchstone
Agilent® P2D
Agilent S2D
AMP
If you set NonLinearData
using rfdata.ip3
or
rfdata.power
, then the property is converted from scalar OIP3
format to the format of rfdata.ip3
or
rfdata.power
.
h = rfckt.amplifier
returns an amplifier circuit
object whose properties all have their default values.
h = rfckt.amplifier('Property1',value1,'Property2',value2,...)
sets properties using one or more name-value pairs. For example,
rfckt.amplifier ('IntType','Cubic')
creates an RF
amplifier circuit that uses cubic interpolation. You can specify multiple
name-value pairs. Enclose each property name in a quote.
analyze | Analyze RFCKT object in frequency domain |
calculate | Calculate specified parameters for rfckt objects or rfdata objects |
plotyy | Plot specified parameters on X-Y plane with Y-axes on both left and right sides |
circle | Draw circles on Smith Chart |
extract | Extract specified network parameters from rfckt object or data object |
The analyze
function computes the AnalyzedResult
property using the data stored in the rfckt.amplifier
object
properties as follows:
The analyze
function uses the data stored in the
NoiseData
property of the
rfckt.amplifier
object to calculate the noise
figure.
The analyze
function uses the data stored in the
NonlinearData
property of the
rfckt.amplifier
object to calculate OIP3.
If power data exists in the NonlinearData
property, the
block extracts the AM/AM and AM/PM nonlinearities from the power
data.
If the NonlinearData
property contains only IP3 data,
the method computes and adds the nonlinearity by:
Using the third-order input intercept point value in dBm to compute the factor, f, that scales the input signal before the amplifier object applies the nonlinearity:
Computing the scaled input signal by multiplying the amplifier input signal by f.
Limiting the scaled input signal to a maximum value of 1.
Applying an AM/AM conversion to the amplifier gain, according to the following cubic polynomial equation:
where u is the magnitude of the scaled input signal, which is a unitless normalized input voltage.
The analyze
function uses the data stored in the
'NetworkData'
property of the
rfckt.amplifier
object to calculate the group delay
values of the amplifier at the frequencies specified in
freq
, as described in the analyze
function reference page.
The analyze
function uses the data stored in the
NetworkData
property of the
rfckt.amplifier
object to calculate the S-parameter
values of the amplifier at the frequencies specified in
freq
. If the 'NetworkData'
property contains network Y-parameters or Z-parameters, the
analyze
function first converts the parameters to
S-parameters. Using the interpolation method you specify with the
IntpType
property, the analyze
method interpolates the S-parameter values to determine their values at the
specified frequencies.
Specifically, the analyze
function orders the
S-parameters according to the ascending order of their frequencies,
fn. It then 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 five different frequencies.
For more information, see “One-Dimensional
Interpolation” and the interp1
reference page.
As shown in the preceding diagram, the analyze
function
uses the parameter values at fmin,
the minimum input frequency, for all frequencies smaller than
fmin. It uses the
parameters values at fmax, the
maximum input frequency, for all 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 amplifier
behavior.
[1] EIA/IBIS Open Forum. Touchstone File Format Specification, Rev. 1.1, 2002 (https://ibis.org/connector/touchstone_spec11.pdf).
rfckt.datafile
| rfckt.mixer
| rfckt.passive
| rfdata.data
| rfdata.ip3
| rfdata.nf
| rfdata.noise