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Active Message Threads for June 2011

George Helffrich
2011-06-29 21:18:34 - 2011-06-29 23:53:51
Dear All - (I resending this to the sac-dev list after de- and re-registering). This is a separate topic to the FAP behavior that Sheila Peacock was requesting, hence a different message thread. It was prompted by the exchange on that topic, so while appearing similar is a different question. Here's the question: If EVALRESP produces and handles FAP responses, what is the added functionality of TRANSFER SUBTYPE FAP? It seems that there are two mechanisms to achieve the same response cor… [more]
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Sheila Peacock
2011-06-28 15:36:46 - 2011-06-28 23:34:31
On 06/27/2011 06:39 PM, George Helffrich wrote: > Dear All - > > While metadata might be a good idea, what's suggested here isn't. The key factors are 1) whether to extrapolate or not; 2) how to extrapolate (linearly from extremal two points; to zero at zero or infinite frequency, etc.) The frequency limits aren't fully relevant -- the cut points are, but not the pass points. > > My own view is that SAC should warn the user that some extrapolation is being done and leave it to the user to di… [more]
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Sheila Peacock
2011-06-27 19:55:54 - 2011-06-27 22:57:02
Dear Brian and Arthur and all, <quote> Sheila, I guess there are a couple of options here. I think the easiest is the use the freqlimits option in transfer to limit where the transfer is applied. The other possibility is to implement an option for the FAP transfer to do what you have done and extrapolate the FAP outside it's prescribed range. I think Arthur had some rationale for making the decision we did about the FAP code and not extrapolating, but I cannot remember what it was. Brian… [more]
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Sheila Peacock
2011-06-23 20:13:21 - 2011-06-24 22:58:41
Dear All, I had some odd results from the new subroutine "fap.c" for deconvolving FAP files, and tracked these down to the absence of extrapolation at the low- and high-frequency ends of the FAP table. Two postscripts attached: both generated by: funcgen impulse npts 10000 delta 0.01 transfer to fap subtype <filename> The FAP files are at the end. The first was for a long-period (LP) seismometer, the second for a broadband (BB) seismometer. What I found was that the lower trace in each po… [more]
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09:58:54 v.01697673