Budget Analysis Application Guide
This application guide provides convenient access to examples of various budget analysis calculations for an RF system, chain or line-up.
Using the pull down menu, all examples with their corresponding data-displays can be opened and viewed. The components used in these designs can be replaced with user's own circuit/behavioral block for simulation. Some simulation setup and parameter adjustment may be required to support the replacing component.
Here is a list of the examples, and how the application guide is organized:
In this series of examples, budget analysis calculations are performed on 2-port 2-pin cascaded networks. 13 examples are included in this section of the application guide to illustrate budget analysis. These examples are used to obtain Noise, Gain, Power and non-linearities including third-order intercept and P1-dB compression points. There are also examples that illustrate the selection between alternate paths and exporting of results to an excel spreadsheet.
In this area are found two examples focused on gain and power measurements using either the AC analysis controller or the Harmonic balance controller. Although the Budget Controller is recommended for most budget simulations, in some cases the flexibility of options afforded by using AC or HB simulation may be desireable.
In this example, budget analysis calculations are performed on networks having an arbitrary topology. Gain, Power and VSWR measurements are obtained. If the user replaces the components with their own circuits, some changes may be required in the simulation controller to achieve convergence in highly nonlinear cases.
In this example, the mixer is simulated to see the spurs generated when there is no filtering. The RF frequency is swept and the spectrum at the IF frequency is computed. The MixerIMT2 component is used to model the mixer. The spurious characteristics are provided by a data file in the ".imt" format.
2-Port Cascaded Networks (Using Budget Controller)
"Noise, Power and Intercept Points" demonstrates a typical RF system chain with nonlinear amplifiers, mixer and filters for computing component performance for noise, power and intercept points.
"SOI, TOI points, IM levels and SFDR" demonstrates the various RF budget SOI and TOI measurements.
"Budget Noise Figure Measurements" demonstrates the various RF budget noise measurements.
"1-dB Power Compression Measurements" demonstrates the RF budget P1-dB compression measurements.
"Mixer Performance with Alternate Paths" demonstrates the mixer performance and the use of "pathselect2" component to setup alternate paths.
"Noise Power Measurements" demonstrates the RF budget noise measurements in a system with 20MHz bandwidth.
"Noise, Power and intercept Points with Power Optimization" demonstrates an RF system budget with power optimization.
"Noise, Power and Intercept Point with Swept Frequency" demonstrates an RF system budget with frequency sweep.
"Noise, Power and Intercept Point with Swept Power" demonstrates an RF system budget with power sweep.
"Power, Noise and TOI for AGC loops with/without Pilot Tone" demonstrates 2 designs where budget measurements are computed for AGC loops, one without a pilot tone and the other with a pilot tone.
"Exporting RF Budget Results to Excel" demonstrates how RF budget results can be exported to a text file, in the Comma Separated Values (CSV) format. ADS includes an example of a user-defined Excel spreadsheet. It contains a macro that you can use to post-process an exported CSV file. This Excel macro will process the CSV file into formatted tables and plots for each measurement. The spreadsheet is named "SetUp_Budget_Sheets.xls" and it is located in $HPEESOF_DIR/examples/Tutorial/RF_Budget_Examples_prj.
2-Port Cascaded Networks (Using Budget Expressions)
"Gain and Incident Power Measurements (AC Controller)" demonstrates the budget gain and incident power calculation for a linear cascaded network. The BudPath component is used to define the signal flow.
"Gain, Incident and Reflected Power, VSWR Measurements (HB Controller)" demonstrates various power measurements using the Harmonic Balance controller and measurement expressions. The BudPath component is used to define the signal flow.
Multi-Port Topology Networks (Using Budget Expressions)
"Gain, SNR and Incident Power Measurements" demonstrates RF system budget for multi-port, multi-channel network. To better understand the results, note that there are two non-linear amplifiers in the design. The incident power is different at the two input terminals of the combiner. This is due to the fact that one of the amplifiers looking into the combiner is linear and the other one is non-linear. By changing the "GainCompressionPower" in the non-linear amplifier to around 100 dB (where the amplifier becomes linear) and setting the ripple voltage in the filters to a minimum value of 0.01 dB, you can notice the incident power and gain values match at both the input terminals of the combiner. This shows the advantage of having multiple channels and analyzing the non-linearities in ADS.
Mixer Spurious Response and Spur Tracking
"Mixer Spurs" demonstrates the spurs generated in a mixer when there is no filtering.