the rough paint drawing attached is meant to show a sort of standing wave, where there is a 1,2,1,2,1,2,1,2 pattern: same wavelength but every other cycle is double amplitude.

Is there a name for this particular type of wave? I did a bit of poking around in discussions & texts about standing waves and couldn't find a ready label for it. Thanks!

wave pattern

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    $\begingroup$ Is there a context? I'm not sure if these are possible to realize physically, since they're not smooth curves; there's a kink after every wavelength. $\endgroup$ – QtizedQ Jul 24 '17 at 1:26
  • $\begingroup$ any kinks are just an artifact of a quick & dirty paint mockup, no real kinks intended, a true fixed-point standing wave was intended. $\endgroup$ – Jim the fourth Jul 24 '17 at 3:21
  • $\begingroup$ I'm assuming that this is a plot of wave amplitude vs space (distance). Is this inside a fixed cavity? If not it's not a standing wave but more likely a linear combination (superposition ) of two waves, different frequency. $\endgroup$ – docscience Jul 24 '17 at 3:29
  • $\begingroup$ Standing waves occur where energy is trapped and reflected within a fixed boundary of space. $\endgroup$ – docscience Jul 24 '17 at 3:30
  • $\begingroup$ 2nd thought. Not a linear combination. More likely a modulation of two waves. $\endgroup$ – docscience Jul 24 '17 at 3:32

Realize that a standing wave is the superposition (interference) of a wave upon itself, facilitated by trapping and reflecting the waves within a space with dimensions that match the wave's frequency, or multiples of the frequency.

The wave you've drawn is more than likely a traveling wave and more so the Amplitude Modulation of one sine wave by another. Another name for modulation is signal mixing. The mixing of two signals is simply done by taking their product (multiplying the two signals).

In your specific example both the carrier and information signal are sine waves whose frequencies are close to one another.

If you are able to capture a longer sample of the actual time signal you could analyze it by processing the Fourier transform, and this would reveal the carrier frequency and side bands (information).

  • $\begingroup$ Thanks, very informative. The wave drawn approximates an idealized representation of an annual pattern of behavior. (the drawing represents two years) Inspired by general knowledge that "wave-like phenomena can be observed in lots of places", I'm attempting to show current observation methods are inadequate and, given the basics of sampling theory to set a floor on the minimum required observations, propose an alternative. And here got side tracked thinking, "hmm, I know the behavior doesn't follow a sine wave pattern, I wonder if it fits another common wave pattern?" $\endgroup$ – Jim the fourth Aug 10 '17 at 23:58
  • $\begingroup$ 'Behavior' - like in animals - or like in climate? In either case I might not be thinking in terms of waves but rather model structures that would lead to the wave. I would want to know what the underlying physical structure is that leads to a modulation or modulation like mechanism. In other words the model of the system. $\endgroup$ – docscience Aug 11 '17 at 0:35
  • $\begingroup$ Human behavior, so the wave analogy really is more analogy than physical phenomenon. And more precisely, it's the intent that precedes behavior (student persistence from one semester to the next). I suppose in wave terms, the goal is an interference pattern that reduces the peaks, but that's probably taking the analogy too far. My role is analysis, and for now my goal is limited to demonstrating that a sample rate of once or twice per year is insufficient in the extreme for the information gained to facilitate meaningful projections, much less anything proactive. $\endgroup$ – Jim the fourth Aug 12 '17 at 13:29

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