The phrase and concept “orthogonal” is widely used in engineering, but it is also often misunderstood. Just as both the time domain and frequency domain are two legitimate ways of looking at a signal from different perspectives linked by the Fourier transform, the constellation diagram has a time-domain complement called the eye diagram or eye […]
What is “orthogonal”? (Part 3): signal constellations
The phrase and concept “orthogonal” is widely used in engineering, but it is also often misunderstood. We can look at orthogonal signals in multiple ways: in the time domain, the frequency domain, as a constellation – a presentation which is widely used in the broad discipline referred to as signal processing, and as an eye […]
What is “orthogonal”? (Part 2): signal space
The phrase and concept “orthogonal” is widely used in engineering, but it is also often misunderstood. The formal definition of orthogonal signals does not necessarily mean that they are unrelated or uncorrelated, although that is how the term is often used in casual “engineering speak.” Formally, two vectors are orthogonal if their dot product is […]
What is “orthogonal”? (Part 1): mechanical design
The phrase and concept “orthogonal” is widely used in engineering, but it is also often misunderstood. I was chatting the other day with a non-technical friend and said something like, “Oh, that won’t happen. Those two things are orthogonal.” My friend looked at me and replied with a “huh?” and he was right to do […]
Digital caliper, Pt 2: Implementation and extensions
Use of electronics and capacitive-based position sensing have transformed the caliper, a fundamental and essential instrument of precision linear-dimension measurement. Part 1 of this FAQ looked briefly at the basic mechanical, Vernier, and dial-readout calipers, as well as the micrometer. All these mechanical-only embodiments of the caliper were made obsolete within a few years with […]
Digital caliper, Pt 1: Background and predecessors
Use of electronics and capacitive-based position sensing have transformed the caliper, a fundamental and essential instrument of precision linear-dimension measurement. Making precise measurements across small distances of up to several inches or tens of centimeters is an obvious and fundamental requirement of modern metrology, research, and mass production. But how can that be done accurately, […]
