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Low Frequency spectrum analysis

Posted: Sat Mar 24, 2018 3:04 pm
by jorgito
Hello All,

This is may first post, and I would like to ask your advise or opinions about a possible application of RD.

I used to do some vibration analysis on a cable stayed structure. The process involves taking some 40 measurements with an accelerometer, register all data as 32 seconds of stay vibration, sampled at 1kHz in each axis, Process acceleration data with GNU/Octave as to get vibration spectrum, identify fundamental vibration frequency and from it get the stay's mechanical tension.
The process is a bit cumbersome and definitively not real time.
I plot the response of stays in graphs like the attached image,

Now, my questions:
.- Can I be able to use a RD almost out of the box? I mean, maybe I could make a program for it, but muy last serious program was in C and assembly almost 30 years ago, so I presume some delay in getting up to date...
.- Do you think that a STEMlab 125 - 14 may be used as to get a spectrum comparable in resolution as the attached?
.- I now need to get a plot of vibration spectrum in the field in real time. Do you think it would be possible?

I think it is all for now. Thanks for your time, and best regards,

Re: Low Frequency spectrum analysis

Posted: Wed Apr 04, 2018 2:29 pm
by jorgito
Hello,

First I would make a correction: In my previous post, where it says RD it must be RP

Second, I would post a couple of sample wav files, hoping that somebody could run a spectrum analysis on a RP.
The two signals are 7zipped. The forum cannot accept .wav attachments. If 7z is inconvenient, I could see a way to zip them.
Signal.7z contains:
99-100-168.wav is 17 seconds of 99.5Hz + 100.5 Hz +168 Hz sampled at 1kHz
1-2.wav is 33 seconds of 0.95Hz + 1.05 Hz + 1.7 Hz sampled at 100Hz

I also attach two screen captures of spectra from both signals made with Baudline using a transform size of 16K samples, where the tree peaks can be resolved.

Thanks in advance and kind regards,

Re: Low Frequency spectrum analysis

Posted: Tue Apr 10, 2018 12:28 pm
by amike88
Jupyter could be useful here.

Re: Low Frequency spectrum analysis

Posted: Tue Apr 10, 2018 8:38 pm
by jorgito
It could be usefull, indeed.