Last night while showing some of the spectrum analyzer parts of the AD2, I went into the reasoning behind me starting Contextual Electronics (not at the time). More accurately, it was this story that I was thinking of when I came up with the story behind “Contextual” Electronics (the name). Here you go:

# Why is it called "Contextual" Electronics?

I don’t know how much more “contextual” you need to get, “time domain” to “frequency domain”. From the representation of a signal with respect to time to the representation of the same signal with respect to frequency. I would have thought electrical engineering students in particular would grasp the usefulness of something like that. I find it quite fascinating that there is a mathematical means for accomplishing this. The FFT is not that complicated considering what it does, unless you are doing the calculations by hand, but no one has done that since Joseph Fourier’s days.

I wrote some code once that performed an FFT on a sampled incoming audio signal that consisted of a pair of DTMF tones. It not only accurately identified the two tones but could do it even if the tones were buried in noise of a far greater amplitude. All on a little embedded processor. I currently use FFT to analyse signals from accelerometers to analyse bearing vibration.

You might also find the videos on this site interesting: Albert Michelson’s Harmonic Analyzer

**ChrisGammell**#5

True, true.

But context isn’t about saying the words (the “what”). Context is understanding the importance of that thing (the “why”).

Were you a ham growing up? I feel like that is a key piece that is assumed for a lot of EE education, but it has large impact.

Well yeah, context usually provides clarification and understanding of the “thing”. I suppose that might extend to why the “thing” is important, but that might be somewhat subjective.

I remember a similar situation when I was studying calculus, I asked, “What’s with all these integrals, derivatives and limits, when will we ever use this again?” Some of the questions were then put in context and it changed my view of calculus forever! Suddenly all this dry and boring math became fascinating as we were calculating the trajectories of bullets and cannonballs, the escape velocity of rockets and many other real world examples.

**Disclaimer:** The following is not intended to be taken personally.

I just assumed, perhaps wrongly, that an EE student would have had enough interest in electronics to already be familiar with the concepts of time domain and frequency domain having probably used an oscilloscope and at least seen a spectrum analyzer. I would have expected much more excitement about learning that there was a mathematical method for transforming a signal back and forth between the two domains. The implications of this are fundamental to DSP (Digital Signal Processing). FFTs are used everywhere these days, you probably have more than one app on your phone that uses an FFT, such as that app that can sample a few seconds of a song and then tell you what song it is. When I was younger FFTs were only just becoming fashionable with the emergence of DSP processors.

According to this site only one person has followed the link I posted above. The videos are quite short but demonstrate the elegant simplicity of the Fourier transform, that is they provide **context**.

PS. Oh, and no, I was not a ham.

**ALeggeUp**#8

I have the interest, but have not found a way to wrap my head around this stuff. I watched the videos and that machine looks super cool but I don’t think I’d ever understand it enough to even *use* it, let alone the geniuses that understood it enough to make it.

I’ve never been able to learn like that, the context that I need is to work through a problem where these concepts help solve it. To me, so far, it’s been like someone pointing to a really scary looking tool in the corner and saying that it’s really useful for them without ever seeing them use it for anything.

I keep hoping that my inability to follow this stuff won’t limit me too much on what I’m able to create with this non-formally-educated passion I’m discovering.