What Is A Vector Signal Transceiver (VST)?

By National Instruments Corporation

Software-defined RF test system architectures have become increasingly popular over the past several decades. Almost every commercial off-the-shelf (COTS) automated RF test system today uses application software to communicate through a bus interface to the instrument. As RF applications become more complex, engineers are continuously challenged with the dilemma of increasing functionality without increasing test times, and ultimately test cost. While improvements in test measurement algorithms, bus speeds, and CPU speeds have reduced test times, further improvements are necessary to address the continued increase in the complexity of RF test applications.

To address the need for speed and flexibility, COTS RF test instruments have increased their usage of field-programmable gate arrays (FPGAs). At a high level, FPGAs are reprogrammable silicon chips that you can configure to implement custom hardware functionality through software development environments. While FPGAs in RF instrumentation is a good first step forward, typically these FPGAs are closed with fixed personalities designed for specific purposes and allow little customization. This is where user-programmable FPGAs have a significant advantage over closed, fixed-personality FPGAs. With user-programmable FPGAs, you can customize your RF instrument to the pin so that it is specifically targeted toward your application needs.