Reduce A/V development time with a software-defined hybrid test architecture

Typically, such a customized test system (Figure 1, below) is very rigid and a whole new test system has to be recreated again whenever another standard or device comes about.

Figure 1: Here's an illustration of a hybrid test architecture comprising instruments across a variety of communication buses, which is controlled by the main controller (e.g. a PC or PXI System

Many manufacturers are now beginning to realize the detrimental consequences of the traditional approach and the limitations of these test systems when challenged by the converging complexity inherent in modern devices. Thus, it is imminent that manufacturers will adopt the new method for A/V test known as the software-defined approach.

A/V devices are now cramped full with modern technologies and multiple functional abilities to support various industry-defined standards to meet the customers' demanding needs.

To stay ahead of competition, manufacturers have to innovate to cut down their development and test time, shorten time-to-market, and come up with a flexible test system capable of testing a broad spectrum of products that will pare down test and development costs as well.

A software-defined approach to A/V testing (Figure 2, below) is the new and innovative approach, providing A/V manufacturers the edge needed to push their new products to market faster. This concept to A/V testing will be the definitive approach for the future.

Figure 2: Shown is the software-defined approach towards test adopting a hybrid test architecture. The main controller will control all the test instruments, and handle the testing processes and programs required for each DUT.

In short, there is only a set of physical test instruments connected to a main controller where the software program will determine the test required depending on the DUT. Let's look in more detail on how this can be achieved.

Utopian approach
Remember the main objective for a software-defined approach in A/V testing is to reduce expenses and time during test and development stages.

Note that there is no "one size fits all" methodology. To create a cost-effective and flexible test system, the utopian approach is to build a hybrid system that combines test instruments from various platforms such as PXI, GPIB, VXI and LXI that allows engineers to choose the best approach for each test application in software.

With a variety of communication buses available, each with its own strengths, hybrid systems are a good option for test systems since they provide greater system flexibility. When you choose only one bus or platform for a system, you are limited to the instrumentation available for that bus.

This limitation prevents you from adopting another instrument that might be better suited for your system needs. When selecting instruments, you want to choose instruments based on specifications like performance, accuracy and measurement availability.

By removing the restriction of using only one bus for the system, you open up the possibilities for instrumentation. Some buses and platforms provide highly specialized instrumentation, while others provide instruments at a better price and performance combination.

Test instrument makers acknowledge that no single instrument architecture is superior in every aspect. A hybrid test system allows A/V test developers to shop around the market for a wider range of test instrumentation.

From traditional test-specific box-instruments using GPIB or LAN/LXI communication buses to modular instruments using the high-bandwidth PXI/PXI Express or VXI bus, developers can merge the best of each heterogeneous buses and platforms to suit their testing requirements.

Such systems are long-term cost-effective solutions to achieve test system longevity by selecting appropriate test instruments for a wider range of DUT.

The design flexibility of a hybrid architecture lets test developers strike a balance between the optimized functionality of dedicated instruments and the ability of virtual instruments to quickly address new test requirements.

For instance, high power or extreme precision measurement or generation may require a GPIB or LXI instrument, while high-speed digitization may need PXI or PXI Express.

On top of this, upgrading and expanding the capabilities of a hybrid test system is made simple with the support of multiple communication buses—from daisy-chaining GPIB box-instruments to additional PXI/ PXI Express modular instruments into the PXI chassis.

In the heart of the hybrid test system, there will be a main controller, which controls all the test instruments via a central operating system. This holds key to be the centerfold of a software-de- fined approach towards test.

This concept allows test developers to control all the connecting test instruments, synchronize the test process, optimize the test program and modify the existing test codes for testing of another product using the same instruments. In short, within the same controller, there can be various test programs and parameters to perform tests for various DUTs.

Only the testing parameters of each product will differ from the next, but the testing methodology of A/V standards or functions remains the same. This statement holds especially true in the A/V testing context where a number of test requirements are similar among various products. Suffice to say, having the ability to re-use existing software test programs is a very favorable advantage to test developers.