Using the Budget Controller

This section will help you decide when to use the Budget controller, and introduces the basic requirements of an RF system design.

License Requirements

The Budget controller will use the Harmonic Balance simulation license (sim_harmonic) or the RF System simulation license (sim_syslinear). You must have one of these licenses to run simulations using the Budget controller. You can work with the examples described in Performing Budget Simulations without the license, but you will not be able to simulate them.

When to Use RF Budget Analysis

Use the Budget controller to perform budget analysis on an RF system. This RF system budget analysis provides a simple and easy-to-use capability to determine the linear and nonlinear characteristics of an RF system comprising a cascade of two-port, two-pin linear or nonlinear components. Each component in the RF system chain must have an S-parameter representation.

Using the Budget controller provides you with the following benefits:

• Easily accessible user interface to set up your budget analysis.
• Provides a large number of built-in budget measurements that you can select.
• Provides improved budget noise measurements.
• Enables you to modify your simulation by using tuning, parameter sweeps, optimization, yield analysis, etc.
• Enables you to include AGC loops in your design to control gain and set power levels at specific points in the RF system.
• Enables you to select between alternate budget paths.
• Export results in ASCII files for use in third-party tools, including Microsoft Excel.

How to Use the Budget Controller

To use the Budget controller, start by creating an RF system design containing cascaded two-port, two-pin components. For a successful analysis, be sure your design follows these requirements:

• Apply ports to the input and output of the two-pin cascaded network. Use either P_1Tone or P_nTone power sources to drive the input. Terminate the end of the cascaded network using port-impedance terminations ( Term or R ). Verify impedance is set to 50 ohms.
• Do not use any components with three or more pins in your design except for S2P, AGC_Amp, AGC_PwrControl, and PathSelect2.
• Use only the MixerWithLO component to define mixers in the RF system. Using any other mixer component, such as Mixer2, with the Budget controller will result in the frequency conversion of the mixer being ignored during simulation.
• Add the Budget component to the design from the Simulation-Budget palette or library. Double-click the controller to open its setup dialog box. Click Help from the dialog box for descriptions about each field.
  • On the Setup tab, you may choose to enable Auto format display with overwrite. This causes the controller to send a request to the Data Display to automatically display the simulation results in tables and plots at the end of the simulation.
  • On the Measurements tab, select the system cascade measurements required to be evaluated. Cascade measurements produce a measurement value at each system node. For example, a system with five components will produce five values for each cascade measurement.
    You may choose to not select any cascade measurements, in which case only the system summary measurements will be evaluated. Summary measurements define overall system performance from input to output.

The following table lists the components located on the Simulation-Budget palette and library that are commonly used for budget simulations and sweeps.

Components Available in the Simulation-Budget Palette and Library

Component	Description	Comments
Budget	Budget simulation controller	Budget controller must be used to perform budget analysis
SweepPlan	Sweep plan controller
ParamSweep	Parameter sweep controller
P_1Tone	Power source: single frequency
Term	Port impedance termination
AGC_Amp †	Voltage-controller amplifier	Amplifier for use in AGC loops
AGC_PwrControl †	AGC loop power control
MixerWithLO †	RF Mixer with internal oscillator	Required for defining mixers used in the RF system
PathSelect2 †	RF path selection from two paths
DisplayTemplate	Automatic display template
MeasEqn	Simulation measurement equation

† Components AGC_Amp, AGC_PwrControl, MixerWithLO, and PathSelect2 are conveniently listed in this library to build RF systems for budget analysis. They may also be used in other Analog/RF simulations. Details about these components are available in the System Models documentation.

Example Designs

For examples of designs prepared for RF system budget analysis, see the simulation project provided at:
$HPEESOF_DIR/examples/Tutorial/RF_Budget_Examples_prj

For demonstrations of various simulation setups, see Performing Budget Simulations.