PSN-L Email List Message
Subject: Re: Integrating in WinQuake
From: ChrisAtUpw@.......
Date: Sun, 22 Nov 2009 19:22:18 EST
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
In a message dated 22/11/2009, rsparks@.......... writes:
For some=20
reason, I got to thinking about the difference between
acceleration=
and=20
velocity detectors today, maybe prompted by your
comment (a few days=
ago)=20
about using WinQuake to double integrate the
data to convert acceler=
ation=20
data to displacement data. The problem is
that WinQuake (so fa=
r as I=20
can determine) does not allow double
integration of the data. =
Only=20
one integration operation is allowed.
Hi Roger,
Have you checked Prof Wielandt's graphs of th=
e=20
various output systems on psn?
Why does this matter? Until today,=
I had=20
concluded that my
magnet-coil detection system was a velocity system=
that=20
only needs one
integration to convert to displacement. But tod=
ay I=20
thought about what
happens if my seismometer (a vertical) was placed=
on a=20
rocket that
boosted to a steady velocity. My seismometer would=
only=20
detect the
acceleration, not the steady state velocity. Hence,=
my=20
detector must be
an acceleration device. Thus I have a logical=
=20
reason to do the second
integration of data.
Are you confusing detectors which have 'DC'=
as well=20
as 'AC' sensitivity, with 'AC' only detectors?
Your mass tries to stay stationary. If you gi=
ve the=20
frame a small velocity, the coil moves in the magnetic field giving an out=
put=20
proportional to that velocity.
Regards,
Chris Chapman
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