## PSN-L Email List Message

**
Subject: Re: Integrating in WinQuake**

From: "Geoffrey" gmvoeth@...........

Date: Sun, 22 Nov 2009 18:06:46 -0700

Velocity = FT/SEC
ACCELERATION = FT/SEC^2
DISPLACEMENT = FT
Seems to me like it may be simple to convert between these various forms
----- Original Message -----
From:
To:
Sent: Sunday, November 22, 2009 5:22 PM
Subject: Re: Integrating in WinQuake
> In a message dated 22/11/2009, rsparks@.......... writes:
>
> For some reason, I got to thinking about the difference between
> acceleration and velocity detectors today, maybe prompted by your
> comment (a few days ago) about using WinQuake to double integrate the
> data to convert acceleration data to displacement data. The problem is
> that WinQuake (so far as I can determine) does not allow double
> integration of the data. Only one integration operation is allowed.
> Hi Roger,
>
> Have you checked Prof Wielandt's graphs of the various output systems
> on psn?
>
> Why does this matter? Until today, I had concluded that my
> magnet-coil detection system was a velocity system that only needs one
> integration to convert to displacement. But today I thought about what
> happens if my seismometer (a vertical) was placed on a rocket that
> boosted to a steady velocity. My seismometer would only detect the
> acceleration, not the steady state velocity. Hence, my detector must be
> an acceleration device. Thus I have a logical reason to do the second
> integration of data.
>
>
> Are you confusing detectors which have 'DC' as well as 'AC' sensitivity,
> with 'AC' only detectors?
>
> Your mass tries to stay stationary. If you give the frame a small
> velocity, the coil moves in the magnetic field giving an output proportional to
> that velocity.
>
> Regards,
>
> Chris Chapman
>
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