Hello Folks,
I'm John Marrinan, and I'll be your visiting expert this week on all things oscilloscopes. I work as a field application engineer for Tektronix in the UK. My core job is to support our customers for complex time domain applications such as high speed serial analysis, embedded system debugging, optical telecommunications and high energy physics. I'd like to start though by giving a brief history of scopes, the role the play in society and what I think the future holds for oscilloscopes.
The traditional scope as we know it was based on Cathode Ray Tubes (CRTs) invented in the late 19th century by Karl Braun. These replaced order oscillographs and galvanometers giving clearer and more efficient views of voltage over time. CRT based scopes used electrically charge, beam forming plates to excite a phosphors coated screen with in incoming oscillating signal. By sweeping one of these sets of plates we could steer the beam across the screen, drawing the waveform. In the early 1920s they became much more common in research labs. After World War II Howard Vollum and Jack Murdock, the founders of Tektronix, invented a "triggered" giving the ability to steadily display repeating signals.
The next major advancement in scopes was the introduction of the digital storage scope in the mid-80s by Walter LeCroy. Digital scopes allowed for higher bandwidths, complex triggering, single shots and post-processing. Digital scopes are fundamentally based on A/D converters and Nyquist theorem. This technology is still the backbone of scopes today and will be into the future.
Today the drive in the scope market leverages improvements in signal process to integrate more of features and functionality. Logic analysis, protocol decoders, spectrum analysis are just some of these features we see today. There still is incessant drive for more bandwidth at the bleeding edge, with applications should as coherent optics pushing bandwidths to 65GHz today, and even 70GHz or 100GHz in the near future. At these speeds T&M companies are lusing cleaver techniques such as digital bandwidth interleaving or asynchronize time interleaving to break through the limitations of A/D and Pre-amplifier technology. The bulks of scopes and scope users don’t need these bandwidth of course, but in the middle-ranges multi-domain features are such as combined protocol, scope and spectral analysis are now needed by embedded engineers to quickly integrate wireless chip sets into our ever connect world. Other trends I see are for more channels (4 phase buck converters), or modularity and shrinkage through PXI and USB.
The oscilloscopes really touches every aspect of modern life whether we know it or not. Whether it is being used as an embedded system debug tool in the design of the latest smartphone or if it is assisting in the creation of defence technologies or being used in coherent optical research for the delivery 100G , 400G or 1Tb communication links used for long haul telecommunications. The ever bandwidth hungry world of Facebook, Google and Netflix to name just a few require more and more capacity in the backbone. Research in fibre, photonics and DSP essential to this industry heavily relies on data acquisition from scopes.
The other trend in our lives is RF Everywhere. From the Internet of Things to Smartphones to Wireless access we all embrace and rely on connectivity. Bluetooth, Zigbee, RFIB and WLAN chipsets are becoming more and more pervasive in embedded system. The challenge for digital design engineers is to integrate the scary world "dbs" and "phase noise" into their "bits" and "bytes" product. Integrated scopes such as mixed signal oscilloscopes or mixed domain oscilloscopes, give engineers the tools to view the interaction between signals and system in both the time and frequency domain.
What's the future for scopes?! Your guess is as good as mine. What I certainly think you will continue to see is more integration of boxes on your lab bench into a single product, and I believe that this product will fundamentally be a scope. There will be more miniaturisation and improved performances in modular based scopes. And there will be a greater influence by the consumer world on the test and measurements world. By this I mean smartphone type interfaces on scopes, instrument control though tablets, and more customisation with 'widgets and apps'.
At the very highest end of research things will stand still and there will be no change at all in my opinion…they'll just want higher bandwidths, faster sample rates and more accuracy like they've always done!!
I would love to hear your feedback and comments on any of these topics over the coming weeks
I'll also be talking about the following topics this week and next
1.
2.
3. All You've Ever Wanted To Know About A Modern Scope's Architecture
References
http://www.ehow.com/about_5817217_history-oscilloscopes.html
http://en.wikipedia.org/wiki/Digital_storage_oscilloscope
http://en.wikipedia.org/wiki/Oscilloscope#Digital_oscilloscopes
