RF System DesignGuide

The RF System DesignGuide configures transmitter and receiver chains using behavioral system models. The DesignGuide provides a complete tool kit to interactively explore Transmitter/Receiver systems at the top level as part of an integrated design process. The inherent capability of ADS allows you to replace all the behavioral models with transistor level circuits. The DesignGuide also facilitates design of a transmitter or receiver by incorporating schematics and data displays that have been pre-configured to create, simulate and measure the performance of the system.

You can use the Transmitter/Receiver Topologies templates to define a system configuration, then proceed to characterize the performance with respect to quantities such as Noise Figure, Carrier-to-Noise Ratio, Carrier-to-Intermodulation Distortion, etc. The final performance measurement is then observed as the given modulation is applied and quantities such as ACPR and EVM are measured. If more sophisticated sources are required, the Co-Simulation Topologies can be used to easily interface with either a user-defined Ptolemy source or one of the available libraries.

Features at a Glance

Transmitters and Receivers

• Single-Stage and Double-Stage UpConversion
  
• Single-Stage and Double-Stage DownConversion
  

Types of Measurements

• Noise Figure(table)
  
• Carrier to Noise Ratio (table)
  
• Carrier to Intermodulation Products (table)
  
• Spurious Response with Swept Input Freq (table and graph)
  
• Spurious Response with Swept LO Freq (table and graph)
  
• System Large Signal S-parameters (graph)
  
• Gain Compression (Graph)
  
• Carrier to Intermodulation Products (Graph)
  

Source Modulation

• PI/4 DQPSK
  
• QPSK
  
• 16, 64, 256 QAM
  
• IS-95 Forward and Reverse Link
  
• Cdma 2000 - Compliant Forward and Reverse Link
  

Example RF Systems

• Data Over Cable Network
  
• 16 QAM System
  
• GSM System
  
• Bluetooth Receiver
  
• GSM Receiver
  
• OFDM Receiver
  

Additional RF/Analog Sources

• CDMA forward and reverse link
  
• CDMA2000 forward and reverse link
  
• WCDMA forward and reverse link
  
• GSM/EDGE forward and reverse link
  
• WLAN(11a/11b) burst mode, CCK, CCK Burstmode, PBCC, PBCC BurstMode
  

Design Flow

With the RF System DesignGuide, the general design flow for a transmitter or receiver consists of a three-step process:

1. Creation of the converter topology.
   
2. Measurement of the system to ensure that the specifications can be met. The system tests usually involve Carrier-to-Noise Ratio, Carrier-to-Intermodulation, Noise Figure, Spurious Response, and others. This initiates an iterative process between the choice of system architecture and the system measurements.
   
3. Measurements of the system using the required signal modulation. These tests may involve Adjacent Channel Power Ratio, Error Vector Magnitude, Peak to Average Ratio, and others.
   

Ultimately you would like to integrate the analog system with the DSP portion of the communication system. For this integration, a more accurate representation of the modulation format can be accomplished using Ptolemy co-simulation. Examples of simulation features that are part of the RF System DesignGuide include communication formats such as data over cable network, 16 QAM System, GSM System, Bluetooth Receiver, GSM Receiver, and OFDM Receiver.

The following screen capture shows the simulation result for a CDMA2000 Communication System.

View Full-Sized Image (40 KB)
RF System DesignGuide: Simulation Results, CDMA2000 Communication System

License Dependency Table

Click on the following link to see a table of dependencies that shows which simulator licenses are required for the various test benches in this DesignGuide:

• RF System DesignGuide License Dependency Table (PDF file, 8 KB)
  

Technical Articles

• Cory Edelman, Improving the Predictability of RF/DSP Transmitter Design, Communication Systems Design, August 1999.   Current issue: Communication Systems Design.
  

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