Computer Hardware Blog

Oscilloscopes and waveform generators have long been the tools of choice for Research & Development laboratories. Since the oscilloscope was first invented in 1897, bench-top instrumentation has become increasingly sophisticated and complex. The oscilloscope has gone from a simple, bulky CRT based device with basic triggering functions to a slim, portable model with a much larger array of features. This has provided the design engineer with a much more powerful fault finding tool. Functionality such as automatic frequency display, peak to peak voltage display, rms voltage display, non-event triggering and FFT analysis are now standard features in even the most basic instruments.

With the rapid upward trend in processing power, PCs are increasingly used in test applications, particularly at the end of production lines. When connecting an instrument directly to a host PC in a rack, the functionality is useful but the space taken up can be restrictive. To counteract this, a number of PCI based instruments have begun to appear in the marketplace providing the full functionality of a scope or waveform generator in the form-factor of a PCI card. This gives the added advantage of having one local display avoiding confusion to the operator with many different screens when using separate test equipment. It also gives full control of the instrument to the PC which for example allows windowing of signals. This is where a UUT is tested and compared to a pre-defined window of acceptance. If the signal falls inside this window the unit is passed. If products are incorrectly failed by the system, the tolerance of the window can be adjusted until an optimum level is reached.

As PC’s becomes increasing popular in industry being adopted as a way to automate test platforms, using a standard desktop PC is never going to withstand the environmental and vibration conditions some test rigs are expected to work in. With this a new technology evolved called PXI (PCI eXtension for Instruments). PXI is still based on a PC platform however offers the additional features of synchronisation between plug in I/O boards to improve triggering and provide a rugged solution that makes it an ideal solution for application like the Military or Aerospace industries.

Test & measurement technology has come a very long way in the past 100 years. The oscilloscope still has its place in the laboratory but with the rapid development of PC based instrumentation and the subsequent emergence of technologies such as PXI it is clear that today’s test applications stretch far wider than ever before. Given the rapid pace of development and innovation it is inevitable that test instrumentation will only continue to improve.

Amplicon Ltd www.amplicon.co.uk