Path: news.mathworks.com!not-for-mail
From: "SmartEngineer" <smartengineer@mathworks.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Energy Density Spectrum to Time Series
Date: Tue, 2 Dec 2008 01:30:17 +0000 (UTC)
Organization: The MathWorks, Inc.
Lines: 14
Message-ID: <gh2339$2fc$1@fred.mathworks.com>
References: <gh0r9m$hl6$1@fred.mathworks.com> <gh0s5q$47i$1@fred.mathworks.com>
Reply-To: "SmartEngineer" <smartengineer@mathworks.com>
NNTP-Posting-Host: webapp-02-blr.mathworks.com
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: 8bit
X-Trace: fred.mathworks.com 1228181417 2540 172.30.248.37 (2 Dec 2008 01:30:17 GMT)
X-Complaints-To: news@mathworks.com
NNTP-Posting-Date: Tue, 2 Dec 2008 01:30:17 +0000 (UTC)
X-Newsreader: MATLAB Central Newsreader 317601
Xref: news.mathworks.com comp.soft-sys.matlab:504275



> typically you go from an amplitude and phase representation back to a time series with ifft.  but that requires both amplitude and phase to properly recreate the original wave.  if the 'energy density' is just a magnitude you could try to use ifft, but without phase information it is unlikely that it would faithfully reproduce the original waveform.  it would of course have the same spectrum magnitude, but not necessarily the the same as the original.

Hello David 
   
1. What I have is probably a magnitude spectrum...How about using a random phase.Does it help?

2. Also Can you please explain the last line "...it would of course have the same spectrum magnitude, but not necessarily the the same as the original."...Im not clear what actually you mean here

3. ifft of the Energy Density Function...does it directly give the time series?

Your suggestions will be very helpful.Thank you.

Regards