rfbudget
Create RF budget object and compute RF budget results for chain of 2-port elements
Description
Use the rfbudget object to create an rfbudget element to
calculate RF budget results of a circuit. You can use any 2-port element in this circuit
such as amplifier,
nport, or
modulator. Open
the complete rfbudget circuit in an RF
Budget Analyzer app. You can also export the completed circuit to RF Blockset™.
Creation
Syntax
Description
rfobj = rfbudget creates an rfbudget
object, rfobj, with default empty property values.
rfobj = rfbudget(
creates an RF budget object from the input RF elements, and independently
computes an RF budget analysis at the specified input frequencies, available
input power, and signal bandwidth. The input arguments are stored in the
elements,inputfreq,inputpwr,bandwidth)Elements, InputFrequency,
AvailableInputPower, and
SignalBandwidth properties. The analysis results are
stored in dependent properties. By default, if any of the input properties
are changed, the object recomputes results.
rfobj = rfbudget(___,sets
the autoupdate)AutoUpdate property. Setting
AutoUpdate to false turns off automatic budget
recomputation as parameters are changed. You can use this syntax with any of
the previous syntaxes.
rfobj = rfbudget(...,Name,Value)creates RF budget
object with additional properties specified by one or more name-value pair
arguments. Name is the property name and
Value is the corresponding value. You can specify
several name-value pair arguments in any order as Name1,
Value1, ...,
NameN, ValueN. Properties not
specified retain their default values.
Properties
Object Functions
show | Graphical summary of all relevant spurs and spur-free zones |
computeBudget | Compute results of rfbudget object |
exportScript | Export MATLAB code that generates RF budget object |
exportRFBlockset | Create RF Blockset model from RF budget object |
exportTestbench | Create measurement testbench from RF budget object |
rfplot | Plot cumulative RF budget result versus cascade input frequency |
smithplot | Plot impedance transformation for selected matching network on smith chart |
polar | Plot specified object parameters on polar coordinates |
Examples
Default RF Budget
Open a default RF budget object.
obj = rfbudget
obj =
rfbudget with properties:
Elements: []
InputFrequency: [] Hz
AvailableInputPower: [] dBm
SignalBandwidth: [] Hz
Solver: Friis
AutoUpdate: true
RF Budget Analysis of Series of RF Elements
Create an amplifier with a gain of 4 dB.
a = amplifier('Gain',4);Create a modulator with an OIP3 of 13 dBm.
m = modulator('OIP3',13);Create an nport using passive.s2p.
n = nport('passive.s2p');Create an rf element with a gain of 10 dB.
r = rfelement('Gain',10);Calculate the rf budget of a series of rf elements at an input frequency of 2.1 GHz, an available input power of -30 dBm, and a bandwidth of 10 MHz.
b = rfbudget([a m r n],2.1e9,-30,10e6)
b =
rfbudget with properties:
Elements: [1x4 rf.internal.rfbudget.Element]
InputFrequency: 2.1 GHz
AvailableInputPower: -30 dBm
SignalBandwidth: 10 MHz
Solver: Friis
AutoUpdate: true
Analysis Results
OutputFrequency: (GHz) [ 2.1 3.1 3.1 3.1]
OutputPower: (dBm) [ -26 -26 -16 -20.6]
TransducerGain: (dB) [ 4 4 14 9.4]
NF: (dB) [ 0 0 0 0.1392]
IIP2: (dBm) []
OIP2: (dBm) []
IIP3: (dBm) [ Inf 9 9 9]
OIP3: (dBm) [ Inf 13 23 18.4]
SNR: (dB) [73.98 73.98 73.98 73.84]
Show the analysis in the RF Budget Analyzer app.
show(b)
Plot Cumulative Output Power and Gain of RF System
Create an RF system.
Create an RF bandpass filter using the Touchstone® file RFBudget_RF.
f1 = nport('RFBudget_RF.s2p','RFBandpassFilter');
Create an amplifier with a gain of 11.53 dB, a noise figure (NF) of 1.53 dB, and an output third-order intercept (OIP3) of 35 dBm.
a1 = amplifier('Name','RFAmplifier','Gain',11.53,'NF',1.53,'OIP3',35);
Create a demodulator with a gain of -6 dB, a NF of 4 dB, and an OIP3 of 50 dBm.
d = modulator('Name','Demodulator','Gain',-6,'NF',4,'OIP3',50, ... 'LO',2.03e9,'ConverterType','Down');
Create an IF bandpass filter using the Touchstone file RFBudget_IF.
f2 = nport('RFBudget_IF.s2p','IFBandpassFilter');
Create an amplifier with a gain of 30 dB, a NF of 8 dB, and an OIP3 of 37 dBm.
a2 = amplifier('Name','IFAmplifier','Gain',30,'NF',8,'OIP3',37);
Calculate the RF budget of the system using an input frequency of 2.1 GHz, an input power of -30 dBm, and a bandwidth of 45 MHz.
b = rfbudget([f1 a1 d f2 a2],2.1e9,-30,45e6)
b =
rfbudget with properties:
Elements: [1x5 rf.internal.rfbudget.Element]
InputFrequency: 2.1 GHz
AvailableInputPower: -30 dBm
SignalBandwidth: 45 MHz
Solver: Friis
AutoUpdate: true
Analysis Results
OutputFrequency: (GHz) [ 2.1 2.1 0.07 0.07 0.07]
OutputPower: (dBm) [-31.53 -20 -26 -27.15 2.847]
TransducerGain: (dB) [-1.534 9.996 3.996 2.847 32.85]
NF: (dB) [ 1.533 3.064 3.377 3.611 7.036]
IIP2: (dBm) []
OIP2: (dBm) []
IIP3: (dBm) [ Inf 25 24.97 24.97 4.116]
OIP3: (dBm) [ Inf 35 28.97 27.82 36.96]
SNR: (dB) [ 65.91 64.38 64.07 63.83 60.41]
Plot the available output power.
rfplot(b,'Pout')
view(90,0)
Plot the transducer gain.
rfplot(b,'GainT')
view(90,0)
Plot S-parameters of an RF system on a Smith Chart and a Polar plot.
s = smithplot(b,1,1,'GridType','ZY');
p = polar(b,2,1);
Harmonic Balance Solver for Nonlinear RF Budget Analysis
Create two modulators, m1 and m2, with output-referred second-order intercept set to 20 and available power gain set to 3.
m = modulator('Gain',3,'OIP2',20,'ImageReject',false,'ChannelSelect',false); m2 = modulator('Gain',3,'OIP2',20,'ImageReject',false,'ChannelSelect',false);
Create a RF budget object specifying the input frequency of the signal, power applied at cascade, and signal bandwidth. Select HarmonicBalance as solver method to compute nonlinear effects such as IIP2 and OIP2.
b = rfbudget([m m2],2.1e9,-30,100e6,'Solver','HarmonicBalance')
b =
rfbudget with properties:
Elements: [1x2 modulator]
InputFrequency: 2.1 GHz
AvailableInputPower: -30 dBm
SignalBandwidth: 100 MHz
Solver: HarmonicBalance
WaitBar: true
AutoUpdate: true
Analysis Results
OutputFrequency: (GHz) [ 3.1 4.1]
OutputPower: (dBm) [ -27 -24]
TransducerGain: (dB) [ 3 6]
NF: (dB) [ 3.01 7.783]
IIP2: (dBm) [ 17 4.457]
OIP2: (dBm) [ 20 10.46]
IIP3: (dBm) [ Inf Inf]
OIP3: (dBm) [ Inf Inf]
SNR: (dB) [60.96 56.19]
Plot Phase and Group Delay of RF System
Create an amplifier with a gain of 4 dB.
a = amplifier('Gain',4);Create a modulator with an OIP3 of 13 dBm.
m = modulator('OIP3',13);Create an nport using passive.s2p.
n = nport('passive.s2p');Create an rf element with a gain of 10 dB.
r = rfelement('Gain',10);Calculate the rf budget of a series of rf elements at an input frequency of 2.1 GHz, an available input power of -30 dB, and a bandwidth of 10 MHz.
b = rfbudget([a m r n],2.1e9,-30,10e6);
Show the analysis in the RF Budget Analyzer app.
rfplot(b)
Group Delay
To plot the group delay, first plot the S11 data for the RF System.
rfplot(b,1,1)
Use the Group Delay option on the plot graph to plot the group delay of the RF system.
Phase Delay
Use the Phase Delay option on the plot graph to plot the phase delay of the RF System.
Algorithms
ABCD parameters are used in the computation of S-parameters of the cascade for Friis Solver. When S21 = 0, conversion to ABCD results in NaNs. For such cases, modifications to the S-parameters are made as follows:
S21 = 0, S11 = -1, and S22 ≠ -1
Connected large resistance (Rp = 1012 Ohm) in parallel with the network.
Connected small resistance (Rs = 10-12 Ohm) in series to the beginning of the network.
S21 = 0, S22 = -1, and S11 ≠ -1
Connected large resistance (Rp = 1012 Ohm) in parallel with the network.
Connected small resistance (Rs = 10-12 Ohm) in series after the network.
S21 = 0, S22 = -1, and S11 = -1
Connected large resistance (Rp = 1012 Ohm) in parallel with the network.
Connected small resistance (Rs = 10-12 Ohm) in series to the beginning of the network.
Connected small resistance (Rs = 10-12 Ohm) in series after the network.
S21 = 0
Connected large resistance (Rp = 1012 Ohm) in parallel with the network.