In practice, the FFT can be used to very easily obtain the integral or 
derivative of a time series (i.e. division or multiplication of all 
spectral points by i*frequency respectively). Since this is already 
built into Winquake, this would be the most efficient method, and is the 
one I always assumed was being used by Winquake. In this case there is 
no finite integration step, since the FFT is a sinusoidal fit, which is 
then played with.

Randall Pratt wrote:

>Arie,
>
>I don't have an answer but I have wondered about this also.  I've considered
>summing as you thought and also the possibility of maybe trapazoidal areas
>with several points.  Another question I have is how the result can begin at
>other than zero displacement with a velocity sensor and zero time at file
>start?  I wonder if the algorithym starts in the middle or from some average
>point and works to the ends?
>
>Randy
>
>----- Original Message -----
>From: "Arie Verveer" 
>To: 
>Sent: Tuesday, June 25, 2002 6:28 AM
>Subject: Integration and Winquake
>
>
>  
>
>>Hi, Just a small question;  When integrating data with Winquake
>>does anyone now the integration period.? I would assume the integrated
>>value is the sum of the y values times 1/ ( sample rate ) over the length
>>of the integration period? . I'm probably wrong, any idea's.
>>
>>
>>Cheers
>>
>>Arie
>>__________________________________________________________
>>
>>Public Seismic Network Mailing List (PSN-L)
>>
>>To leave this list email PSN-L-REQUEST@.............. with
>>the body of the message (first line only): unsubscribe
>>See http://www.seismicnet.com/maillist.html for more information.
>>
>>    
>>
>
>__________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email PSN-L-REQUEST@.............. with 
>the body of the message (first line only): unsubscribe
>See http://www.seismicnet.com/maillist.html for more information.
>  
>



  
  


In practice, the FFT can be used to very easily obtain the integral or derivative
of a time series (i.e. division or multiplication of all spectral points
by i*frequency respectively). Since this is already built into Winquake,
this would be the most efficient method, and is the one I always assumed
was being used by Winquake. In this case there is no finite integration step,
since the FFT is a sinusoidal fit, which is then played with.



Randall Pratt wrote:


  
Arie,

I don't have an answer but I have wondered about this also.  I've considered
summing as you thought and also the possibility of maybe trapazoidal areas
with several points.  Another question I have is how the result can begin at
other than zero displacement with a velocity sensor and zero time at file
start?  I wonder if the algorithym starts in the middle or from some average
point and works to the ends?

Randy

----- Original Message -----
From: "Arie Verveer" <ajbv@............>
To: <PSN-L@..............>
Sent: Tuesday, June 25, 2002 6:28 AM
Subject: Integration and Winquake


  
  

    
Hi, Just a small question;  When integrating data with Winquake
does anyone now the integration period.? I would assume the integrated
value is the sum of the y values times 1/ ( sample rate ) over the length
of the integration period? . I'm probably wrong, any idea's.


Cheers

Arie
__________________________________________________________

Public Seismic Network Mailing List (PSN-L)

To leave this list email PSN-L-REQUEST@SEISMICNE
T.COM with
the body of the message (first line only): unsubscribe
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 for more information.

    
  
  

__________________________________________________________

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