1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

A Interpretation of a signal (sound) spectrum - hydrophones

  1. May 12, 2016 #1
    ooops so obvious sorry! please delete
  2. jcsd
  3. May 12, 2016 #2


    User Avatar
    Homework Helper
    Gold Member

    The 40kHz is from the axis. The fundamental appears at about 0.4 on the scale, which is per 105 Hz, so that is 0.4 x 105 Hz, or 40 kHz.
    As for the rest, it's not at all clear to me. They don't seem to mention the large 210 kHz signal which is the same size as the fundamental. Maybe this is an alias? The symmetry makes me think this.
    The second and third harmonics appear in b,c & d, but as to what causes them there's no indication.
    Edit: I haven't read the paper, though they appear to be claiming the harmonics are due to non-linear effects in the liquid. I would want to check carefully that it's not non-linear effects in the driver.
  4. May 12, 2016 #3
    Thanks for the reply, i just figured it out as i posted and cant delete the thread. Thank you though!!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted