How Far Can USB Testing Go?

The convenience of devices such as memory cards equipped with Universal Serial Bus (USB) connectors can hardly be debated. The USB standard allows simple connection of memory cards, computer peripherals, and accessories to a laptop or desktop personal computer (PC). It is also allowing more and more microwave test instruments to connect to a PC, taking advantage of the processing power already available in the computer and saving some of the cost of a dedicated processor for each different instrument function. Such instruments as power sensors/meters (see story below), signal generators, and digital attenuators are already available with USB interfaces for simple use with a PC and the proper software.

This trend appears to be leading to a full-USB microwave test station. Of course, this would require that certain instruments, such as digital storage oscilloscopes (DSOs) and vector network analyzers (VNAs), are eventually available in USB form and that may not happen. Current USB test functions, such as signal generation and power measurement, are easily coordinated by even basic PCs. But those same PCs may not have the processing power, for example, to coordinate the complex error correction and S-parameter computations performed by a microwave VNA. Test equipment designers dedicate processors to these complex functions, maintaining control over measurement performance. With an "add-on" computer, the same performance levels may not be possible.