I have a laser that I modulate at some frequency, typically 1250 Hz. I have a sensor that tracks what happens inside a reactor when it's illuminated. I am doing Fourier analysis on both the laser modulation signal and the sensor, and extracting the components at 1250 Hz, forming a time series of phases.

I was playing around with these phase relationships in Excel and I came up with this plot. Laser is the x-axis, sensor is the y-axis. I'm trying to think back to college because I swear I've seen something like this before, but would appreciate any commentary!

what is this even

  • 2
    $\begingroup$ Well, by construction, it's a Lissajous curve made with 2 sinusoids of the same frequency, with a particular phase between them: en.wikipedia.org/wiki/… . The elliptical shape is a function of the phase delay whuch depends on the system and your method of measurement. $\endgroup$ – Andy Walls Jul 6 '19 at 10:24
  • $\begingroup$ Lissajous curve! Thank you, that was the term I was trying to remember. $\endgroup$ – Ben S. Jul 6 '19 at 23:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.