Larry
I think it's related:
Maybe all you folks were aware of it but it just came to my attention now. =
Winquake has the nice feature that , after selecting an event file, if you =
select a time window with the mouse and you run a "window" FFT you will see=
 the FFT for that time window. Now display both windows on the same screen =
one below the other. Set the button to display the event=A0 phases. If you =
now use the horizontal scroll bar you can start before the event and scroll=
 thru the event noting how the frequencies change as the phases arrive. I s=
ee this very useful in selecting the filter to use in processing your data.

Regards
Barry
http://www.seismicvault.com

--- On Fri, 1/1/10, Larry Conklin  wrote:

From: Larry Conklin 
Subject: Re: Sensor noise
To: psn-l@..............
Date: Friday, January 1, 2010, 7:30 AM

Barry,

Your goals were a lot more ambitious than mine.=A0 I had no thoughts about=
=20
trying to use the frequency domain to trigger event alerts.=A0 I've pretty=
=20
much concluded that any sort of automatic alert scheme requires a MUCH=20
quieter site than I am able to provide in my residential location.

I have a waterfall display running, but it clearly isn't performing the=20
FFT correctly.=A0 For one thing it looks like the plot is symetrical=20
around the center point (showing "negative" frequemcies"?). And when I=20
run it on a data file that contains just a single sinusoidal signal, I=20
get an output that shows a whole series of lines.=A0 So, I've got some=20
debugging to do, if I ever get around to it.

I found the code (in C) for the transform somewhere and cobbled it into=20
my data logger/replay program.=A0 Kind of a hack job, so I probably=20
deserve the problems I'm having.

.
Larry
I think it's related:
Maybe all y=
ou folks were aware of it but it just came to my attention now. Winquake ha=
s the nice feature that , after selecting an event file, if you select a ti=
me window with the mouse and you run a "window" FFT you will see the FFT fo=
r that time window. Now display both windows on the same screen one below t=
he other. Set the button to display the event  phases. If you now use =
the horizontal scroll bar you can start before the event and scroll thru th=
e event noting how the frequencies change as the phases arrive. I see this =
very useful in selecting the filter to use in processing your data.

=
Regards
Barry
http://www.seismicvault.com

--- On Fri, 1/1/=
10, Larry Conklin <lconklin@............> wrote:

From: Larry Conklin <lconklin@............>
Subj=
ect: Re: Sensor noise
To: psn-l@..............
Date: Friday, January =
1, 2010, 7:30 AM

Barry,

Your goals w=
ere a lot more ambitious than mine.  I had no thoughts about 
tryin=
g to use the frequency domain to trigger event alerts.  I've pretty much concluded that any sort of automatic alert scheme requires a MUCH quieter site than I am able to provide in my residential location.
I have a waterfall display running, but it clearly isn't performing the FFT correctly.  For one thing it looks like the plot is symetrical <=
br>around the center point (showing "negative" frequemcies"?). And when I <=
br>run it on a data file that contains just a single sinusoidal signal, I <=
br>get an output that shows a whole series of lines.  So, I've got
 some 
debugging to do, if I ever get around to it.

I found the c=
ode (in C) for the transform somewhere and cobbled it into 
my data logg=
er/replay program.  Kind of a hack job, so I probably 
deserve the =

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