Test System Synchronization Overview

Test System Synchronization Overview

Last updated: January 16, 2009

Description

Typical test systems include an external controller with a GPIB connection to the test set, an RF (and possible AF) connection between the test set and a mobile station under test, and a serial connection between the mobile station and the external controller.

Synchronizing an external controller with the test set and a mobile station under test ensures that no device does something before it is supposed to, which can cause errors, or does something well after it could have, which wastes time.

Test System

Sequential versus overlapped commands

The test set uses both sequential and overlapped commands:

  • Sequential commands must finish executing before the next command starts to execute.
  • Overlapped commands do not finish executing before the next command starts to execute.

Overlapped commands are more difficult to synchronize because an overlapped operation that started several commands earlier may still be executing as subsequent commands are being parsed out from the input buffer and executed. This can present a problem unless the external controller is properly synchronized to the test set's execution of commands. Overlapped commands allow the test set to use its internal resources as efficiently as possible.

Methods for synchronization

The test set's GPIB command set supports the following methods to achieve synchronization for overlapped commands. In some cases, combinations of these methods will provide the best results:

Methods one and two do not require the external controller to query the test set, nor to perform any branching or decision-making associated with information acquired from the test set.

Methods three through six rely on responses from the test set to an external controller, indicating that some event has occurred. The external controller can then make decisions based on these responses to control the flow of commands to the test set and other devices in the test system.

  1. Force the test set to execute overlapped commands sequentially.
  2. Force the test set to wait until an overlapped command is done executing before executing any more commands.
  3. Query the test set to determine when a command has finished executing.
  4. Query the test set to determine when all commands sent to it have at least begun executing.
  5. Query the test set to determine the current call or data connection processing state.
  6. Program the test set to generate a service request when an operation has completed or the test set is in a certain state.

Commands used for synchronization:

Related Topics


Call Processing State Synchronization

Measurement Event Synchronization

Call Processing Event Synchronization

SYSTem:SYNChronized