## PSN-L Email List Message

Subject: Re: Spring damping
From: Bobhelenmcclure@.......
Date: Thu, 26 Jul 2007 21:11:23 EDT

```I do not know if there is a standard symbol for damping, but "Seismic
Sensors and their Calibration" by Dr. Erhard Wielandt calls it "h". The relation
between Q and h is Q=0.5/h. For critical damping, h=1.0 and Q=0.5.

If the sensor Q is set to 0.707, the damping is also 0.707, and  the sensor
response is identical to a 2nd order Butterworth filter whose corner
frequency is the natural frequency of the pendulum. The corresponding overshoot  is
4.33 per cent. This is where I would like to keep my sensors, even  though my
WQFilter.exe" utility can compensate the data for almost any amount of
under-or-over damping.

Bob

Geoffrey  wrote:
Hello Bob & PSN;

Im not so sure this stuff is correct because
its my understanding that Q  and Damping
are simply inverses of each other just like
Period and  Frequency. I was unable to
get the inverse result simply by
alternately  clicking the buttons
using the same input values.

Like Q = 1 then damping = 1
Like Q = 0.5 then Damping = 2
Like Q = 2  then damping = 0.5
???
Also, Whats the proper symbol for  damping?

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I do not know if there is a standard symbol for damping, but "Sei=
smic=20
Sensors and their Calibration" by Dr. Erhard Wielandt calls it "h". The rela=
tion=20
between Q and h is Q=3D0.5/h. For critical damping, h=3D1.0 and Q=3D0.5.

If the sensor Q is set to 0.707, the damping is also 0.707,=
and=20
the sensor response is identical to a 2nd order Butterworth filter whose cor=
ner=20
frequency is the natural frequency of the pendulum. The corresponding oversh=
oot=20
is 4.33 per cent. This is where I would like to keep my sensors, even=20
though my WQFilter.exe" utility can compensate the data for almost any amoun=
t of=20
under-or-over damping.

Bob

Geoffrey  wrote:  Hello Bob & PSN;

Im not so sure this stuff is correct becauseits my understanding th=
at Q=20
and Dampingare simply inverses of each other just likePeriod and=20
Frequency. I was unable toget the inverse result simply byalternatel=
y=20
clicking the buttonsusing the same input values.

Like Q =3D 1 then damping =3D 1Like Q =3D 0.5 then Damping =3D 2Like Q =3D 2=20
then damping =3D 0.5???Also, Whats the proper symbol for=20
damping?Get=
a sneak peek of the all-new AOL.com.
```