There once was a time when measurement instruments did one thing and one thing only. When Bill Hewlett and Dave Packard designed their first product, an audio oscillator, it needed a simple user interface: three knobs and an on-off switch. The user needed to change frequency (two knobs) and amplitude (one knob). That's all.
Basic RF/microwave instruments such as spectrum analyzers initially performed one task; they provided a plot of amplitude versus frequency, but nothing else. Early VNAs (vector signal analyzers) measured S parameters only. Today's instruments, however, resemble Swiss Army knives in that they can perform many unrelated tasks. VNAs, for example, do much more than measure S parameters. Plus, wide range of engineers and technicians now use them. Versatile instruments, however, have complex internal designs. Their human-machine interactions require considerable research and design efforts.??Designing and developing new measurement science still garner the lion's share of R&D money from instrument manufacturers, but UI (user interface) design is gaining in importance. There are numerous examples of companies who excel at industrial and UI design, Apple in particular. Unfortunately, the RF/microwave test-and-measurement equipment aren't stellar examples of "ease-of-use." The problem arises because of the variety of uses and the diversity of users that each instrument must serve. A UI that appeals to R&D engineers might not appeal to production and test-automation engineers and technicians.