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H/V file and curves interpretation

Posted: Mon May 13, 2024 3:04 pm
by JGD
Greetings

I have a question regarding the results obtained from the H/V file and the corresponding graph, using as example the following H/V:
1a.png
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Image

Which gives the following data in the H/V file:

# GEOPSY output version 1.1
# Number of windows = 20
# f0 from average 2.09757
# Number of windows for f0 = 20
# f0 from windows 1.95021 1.74709 2.17694
# f0 amplitude 5.87638

As you can see, the f0 from average is the one matching the one we see in the graph, and looking for the differences between that one and the f0 from windows i found this old thread viewtopic.php?t=181:
f0 from average is computed by scanning the average curve and identifying the frequency at which the maximum amplitude occurs.
f0 from window is computed differently. The scan is run on each individual curve (corresponding to one window). Several peak values are then extracted. From this population an average and a standard deviation is assessed.
Does this mean that in the graph we obtain, the bold line corresponds to the average curve but the dash lines are the standard deviation from the window computation? So the graph is a combination of both methods to get the fundamental frequency?

Thanks in advance

Re: H/V file and curves interpretation

Posted: Tue May 28, 2024 1:13 pm
by admin
Hi,

There is a missing component in your plot to view "F0 from windows". It is represented by two vertical grey areas, a darker and a lighter. The intersection of the two zone is the average F0 from windows and the width of the area represents the standard deviation.
The average curve is the bold plain line. The dashed lines are the plus and minus one standard deviation curves (geometrical mean).

Best regards,

Marc