Geoffrey,  No I have not see it.   I will look,  Thanks, Ted
----- Original Message ----- 
From: "Geoffrey" 
To: 
Sent: Sunday, July 29, 2007 6:29 AM
Subject: Re: Testing the Folded Pendulum


> Have you seen the seismometer they are building for
> a mars mission ? do you think you could duplicate
> one like that ???
> I think it is only horizontal x-y.
>
> regards;
> geoff
>
> ----- Original Message ----- 
> From: 
> To: 
> Sent: Saturday, July 28, 2007 08:46
> Subject: Testing the Folded Pendulum
>
>
> Hi All,  I finished the Folded Pendulum Sensor.  I will send pictures to 
> anyone interested.  After I test it, and if it works, I will then post the 
> pictures on the internet, like I did on the "Slinky"
>
> All in all, it was a bit of a bear.   I guess the fact it was a new 
> concept, for me, and that I could find only a couple examples, was part of 
> the issue.   Thanks to all who helped me, or I would have never gotten 
> this far.   At this point it seems to be working, but I can qualify it's 
> performance after it is tested.
>
> The two pendulum, one normal, one inverted have the same length, 7.625", 
> The box it is contained in is 32"x24".
> The best working natural period I could measure, was about 6 to 10 
> seconds.  I could obtain 15 seconds but it was too unstable.
> It has been pointed out to me that I should have achieved a longer period 
> using this approach.   Perhaps other articles and examples may show me how 
> to improve the design.
>
> By the way if and when I record earthquakes using the sensor I will post 
> them on PSN as TCIDF, for "Folded Pendulum"
> TCIDzs= "Slinky is setting in the corner.
>
> I do have a question about measuring a sensor's period.  I assume the best 
> way is to remove the damper, tap the arm, and time the cycles.
>
> Q.   Is there another way, to estimate its period, with the damper 
> installed?   On this sensor the damper is difficult to remove.
>
>
> Different Subject
>
> Q.   I don't really understand the FFT in AmaSeis.   If I take one hour of 
> trace, containing road construction noise, and use Control/Fourier 
> Transform/Linear,   I see a large spike at 1.607Hz another at 2.597Hz and 
> some other signals.
> Is this the frequency of the noise?
>
> Q.  I highlighted an earthquake, and using the same steps I see a section 
> of spikes, starting at .2 and ending at .8Hz
> Is that the frequency of the recorded earthquake?
>
> Thanks Again,  Ted
>
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