Thread: RMS of spectral Amplitude

Thanks for reply, but can we trust the value we get in this way? mathematically RMS calculated in time domain should be the same as frequency domain. But using this way I am getting different values.

Best Regards

Mostafa



________________________________
From: George Helffrich <glgrh<at>bristol.ac.uk> on behalf of George Helffrich <George.Helffrich<at>bristol.ac.uk>
Sent: Saturday, January 18, 2014 11:19 PM
To: S Mousavi (smousavi)
Cc: sac-help<at>iris.washington.edu
Subject: Re: [SAC-HELP] RMS of spectral Amplitude

Dear Mostafa Mousavi -

You want to use the WRITESP command to write out your spectrum after FFT, then read back in the file as a time series, e.g.

fg seismogram; fft; writesp am /tmp/fft; read /tmp/fft.am; rms

On 18 Jan 2014, at 19:38, S Mousavi (smousavi) wrote:


Hi
I want to ask if there is any way to get the RMS of Spectral Amplitude in sac ? RMS command in SAC is design for time domain, although it works in frequency domain also but I am not sure about the results. I need to measure the spectral amplitude and I am seeking a way more dependable than taking a maximum amplitude. Is the Hilbert transforming and taking maximum amplitude afterward a good alternative for taking RMS?
Sincerely


S. Mostafa Mousavi
Ph.D. candidate, Geophysics
Center for Earthquake Research and Information
University of Memphis
3876 Central Ave, Suite 3
Memphis, TN 38152
Phone: +1 (202) 304-0084
Email: smousavi<at>memphis.eduhttps://sn2prd0410.outlook.com/owa/redir.aspx?C=aWxCKi-ybkuNzkngCW4UFod6DJLVic8IR52CYvkFuQVTN3CKpjpRKsER7oScRDeVStU6bxWnbGw.&URL=mailto%3abayoung6%40memphis.edu
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George Helffrich
george.helffrich<at>bris.ac.uk<george.helffrich<at>bris.ac.uk>