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Do you recognize this sound?

  • Thread starter Herbert Blenner
  • Start date
H

Herbert Blenner

Jan 1, 1970
0
Don said:
It shows the other signals, certainly. To call it frequency modulation
is nothing more than your chosen interpretation. There is no
justification for that interpretation.

What is your interpretation of a FFT, which shows a prominent nearly
narrow band sinusoid

http://www.members.aol.com/hdblenner/cardinal.htg/trackone0067.jpg

and sounds like a loud noise?

http://www.members.aol.com/hdblenner/cardinal.htg/trackone0067.wav

The wave file contains 16384 points, which facilitates FFT analysis.
Short term spectra show the sinusoid rapidly hopping around 900 Hz. Any
insights you have would be appreciated.

Herbert
 
D

Don Pearce

Jan 1, 1970
0
What is your interpretation of a FFT, which shows a prominent nearly
narrow band sinusoid

http://www.members.aol.com/hdblenner/cardinal.htg/trackone0067.jpg

and sounds like a loud noise?

http://www.members.aol.com/hdblenner/cardinal.htg/trackone0067.wav

The wave file contains 16384 points, which facilitates FFT analysis.
Short term spectra show the sinusoid rapidly hopping around 900 Hz. Any
insights you have would be appreciated.

Herbert
I don't know about rapid hopping. The signal appears to die away, then
reappear at a slightly different frequency. I supposed you could
interpret this as FM, but with the simultaneous amplitude variations
it is also AM. Of course you can represent absolutely any signal as a
combination of these two, so the best I can say is that it is an
unstable noisy tone at around 900Hz, superimposed on broadband noise,
band limited to 300 to 3kHz.

The problem with any FFT is that is just shows you what you have, not
how you made it.

d

Pearce Consulting
http://www.pearce.uk.com
 
M

Mark

Jan 1, 1970
0
wow!!!!

I did that by EAR... I wasn't kidding when I said it sounded familiar
to me.
I spent a bit of time listening to that tape.

Is it the section of the alleged bell sound?

Mark
 
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