The essential role of software in test

Software today is now so integral to the functioning of test equipment that it’s hard to think of instrumentation without it. But those of us who began our careers in the latter part of the 20th century can remember when software was not essential to measurement; the only “software” was a printed user’s manual, and once you’d learned how to use a Simpson or Weston meter, you never looked at the manual again.

Changes began once instruments were built so that they could not only be controlled manually, but also by a desktop computer; since then, there’s been no looking back. Today, software that controls test is created at the initial stage of design using EDA tools that put test structures into silicon. Once the silicon is created, a software suite determines whether it complies with complex performance requirements. As software is assembled, it’s software’s job to emulate parts of the system that aren’t yet ready so that the subsystem being designed can be tested against system performance requirements.

Software has changed the way test hardware is designed as well. Whereas the hardware has advanced so that it can capture and digitize a signal at unprecedented speeds, it is the software that determines how the signal is filtered, analyzed, and presented to the user. The days of using specialized hardware to control an instrument have gone; instruments are now run by general-purpose processors and operating systems.

Not only has this paved the way for virtual instruments — modular instruments whose purpose and functionality are determined by software but even dedicated instruments like oscilloscopes and analyzers come with a broad range of functionality that the user can access in stages by paying a fee for a software “key” that unlocks more valuable capabilities that were built in during manufacturing.

So instrumentation, like most electronic systems, in the course of 50 years has gone from being hardware only, to software and hardware, to being fully integrated systems that can only be described as “ware” ware.