This new series of articles on SIJ aims to highlight the work of many engineers engaged in extreme measurements. I’m going to get the series started with some examples presented at DesignCon 2021, but anyone with an extreme measurement story who wants to participate should send it to: editorial@signalintegrityjournal.com for consideration.

So just what is an extreme measurement?  For the purposes of this blog, we’ll use these four criteria to establish a measurement as being extreme.

1. Measuring a sum and breaking it down into parts, for example through de-embedding.
2. Measurement using equipment or accessories not thought to be capable of the task.
3. Combining different measurement techniques or setups into a single result.
4. Measuring something thought to be immeasurable.

While we could call this “thinking outside the box”, I think that it is an overused phrase.  I prefer to call it lateral thinking.  When my daughters were younger, they both participated in the Odyssey of the Mind program, which encouraged lateral thinking through competitive problems.  It always reminded me of the Apollo 13 dilemma.

…Using a clever solution of a plastic bag, cardstock, a spacesuit hose, and that stuff that holds everything together, duct tape, the engineers in Mission Control mocked up an altered lithium hydroxide filter…. [1]

Figure 1 A picture of the NASA solution that was developed to solve the Apollo 13 mission crisis, saving the lives of the astronauts onboard. [1]

Odyssey of the Mind uses similar thinking.  How exactly does this relate to making measurements?  I will show how to use similar thinking to solve the most difficult measurement challenges, while often performing measurements considered all but impossible.  The basic flow of the measurement is shown in Figure 2. 

The flow chart is essentially an iterative process of defining the barrier to performing the measurement and finding an alternate solution.  Often, this seems like a game of Whack-A-Mole. Each time a solution is applied to find a way past the blockage, another issue seemingly pops up in its place.  The iterative process continues until all the barriers are removed and the measurement is successfully performed.

 Figure 2 A flowchart showing the iterative methodology of performing extreme measurements.

One caveat is that while a “normal method” might work, it could be that the equipment necessary is not available or accessible.  This was certainly the case with the Apollo problem, so we are limited to the instruments and tools that we have on hand.  For our purposes, the lack of optimal or traditional equipment will just be considered one more barrier or obstacle to overcome.

Reference:

[1] Conserving the Creativity that Saved the Apollo 13 Astronauts, Smithsonian Air and Space Museum, April 16, 2020 
https://airandspace.si.edu/stories/editorial/conserving-creativity-saved-apollo-13-astronauts