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mssm22
Germany
10 Posts |
 Posted - 01/21/2009 : 12:07:11 PM
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Hello,
I wounder if you can help me with FFT signal processing. I using origin 8 to calculate the power spectrum for a set of data. The settings are:
Rectangle or hanning window
Science
one sided
Mean square amplitude.
Now, with the rectangle window the normalization (if one can call it so) is correct ( some of the powers except zero frequency value returns the variance of the time data). on the other hand, for the hanning the value is too high mainly because high powers at low frequencies. So I would like to know what i am missing here? is it a factor that i must multiply with or something like that?
Regards |
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fisher_zhang
China
Posts |
Posted - 01/24/2009 : 12:46:21 AM
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Hi, mssm22
Can you send us your data and the version of Origin you are using to tech@originlab.com
You can check the Origin Ver here: Help -> About Origin
Fisher
quote:
Originally posted by mssm22
Hello,
I wounder if you can help me with FFT signal processing. I using origin 8 to calculate the power spectrum for a set of data. The settings are:
Rectangle or hanning window
Science
one sided
Mean square amplitude.
Now, with the rectangle window the normalization (if one can call it so) is correct ( some of the powers except zero frequency value returns the variance of the time data). on the other hand, for the hanning the value is too high mainly because high powers at low frequencies. So I would like to know what i am missing here? is it a factor that i must multiply with or something like that?
Regards
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Edited by - fisher_zhang on 01/24/2009 12:52:27 AM |
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mssm22
Germany
10 Posts |
Posted - 02/04/2009 : 04:06:17 AM
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hi, I know that you guys must be busy, but I sent the data since 10 days now and there is no reply
regards |
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easwar
USA
1964 Posts |
Posted - 02/04/2009 : 10:20:53 AM
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Hi Mohammed,
We had sent a reply on Jan 26th, but our system for some reason truncated part of your e-mail address...we are looking into that issue.
I have sent you a message again, with an OPJ showing results we get, and asked you for further information on what you think is the discrepancy.
Please reply to that message or post details here.
Thanks, and aplogies for the inconvenience.
Easwar
OriginLab
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mssm22
Germany
10 Posts |
Posted - 02/04/2009 : 4:40:23 PM
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hi and thanks
I already sent an email
regards |
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Topic |
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Hanning window