Talk:Cepstrum

message: I know this has been discussed above, but a lot of the above discussion is old, and I don't want my contribution to be lost, especially since it concerns an edit I made. Moreover, I'm going to take this from a slightly different angle: what really makes one definition of "cepstrum" more "correct" than the other? Yes, FFT -> log -> FFT was the original definition, but FFT -> log -> IFFT is obviously useful to many people, and is what a lot of people mean when they say "cepstrum". Why can't it be both? Why does the original definition have to be the One True Definition? This is obviously a somewhat subjective matter. Because of this, I decided that it is not NPOV to declare that a given definition is "correct" and have reworded the article accordingly. - furrykef (Talk at me) 18:11, 27 March 2006 (UTC)
thread_title:  "Correctness" of cepstrum definition 

message: :The real cepstrum uses the logarithm function defined for real values, while the complex cepstrum uses the complex logarithm function defined for complex values also.
I'm not quite sure what this means. Is it saying that the real cepstrum is real FFT -> log -> real FFT? In other words, throwing away the imaginary part after the first FFT as well as the second? I've also seen "real cepstrum" defined as the complex cepstrum with the real components thrown away at the end; which is it? - furrykef (Talk at me) 18:21, 27 March 2006 (UTC)
replies: text: (Rewritten) Components are not usually thrown away but one may choose to reduce each real+imaginary pair of values to a single real value by rotating their vector angle to zero, where the imaginary part becomes zero. That obtains the absolute value of the complex value. Only its phase information is ignored, the new real value keeps magnitude information.Cuddlyable3 11:29, 25 June 2007 (UTC)
thread_title:  "Real cepstrum" 

message: The property that convolutions turn into additions is very important and is indeed a large part of the motivation behind the cepstral domain in the first place. I'm not too good at the math latex stuff so maybe someone can fix that up. --Speedplane 05:14, 5 March 2007 (UTC)
thread_title: Added convolution note

message: New at this. The word "Analysis" is misspelled in the first (BP Bogert, MJR Healy, JW Tukey) reference.Smoo222 (talk) 21:28, 29 June 2009 (UTC)
replies: text: No, it's not. It's a playful alteration of the word in the same way that "cepstrum" is an alteration of "spectrum". - furrykef (Talk at me) 04:38, 30 June 2009 (UTC)
replies: text: Oops! You're right. About 1/3 of the references to that article online have "corrected" the spelling, but indeed, the original was spelled 'alanysis'. Thank you.  Smoo222 (talk) 16:07, 30 July 2009 (UTC)
thread_title:  How to edit "References" section? 

message: In engineering signal analysis the cepstrum is the spectrum of the spectrum ie Ecepstrum=FFT(log(abs(FFT(timesignal))). In speech analysis it is something else involving an IFFT, something like Scepstrum=IFFT(log(abs(FFT(timesignal))).
I very much doubt the two are equivalent and I think it would be a good idea to have sections on each. At the same time I have no great enthusiasm for doing so since Ecepstrum is not very useful. Greglocock (talk) 03:22, 18 September 2013 (UTC)
replies: text: In Lectures "Speech Processing by Computer" (Notes on Computing the IDFT and Cepstrum)  by Professor Leah H. Jamieson we have explanation that those two definitions are interchangeable when considering real even functions, which is the case of log(abs()) function.--46.215.36.139 (talk) 17:17, 21 January 2014 (UTC)
thread_title:  Confusion - two definitions 

message: The picture located here: http://en.wikipedia.org/wiki/File:Cepstrum_signal_analysis.png is very useful for seeing how a cepstrum 'works'; however, it's located within the paragraph defining the four types of cepstra and doesn't have any mention of which type the picture contains.  Can someone clarify?  — Preceding unsigned comment added by 75.155.204.180 (talk) 16:13, 9 April 2015 (UTC)
thread_title:  Minor Ambiguity 

message: I added more information to the introduction in order to explain background and purpose already in the first sentences (for the quick reader, who is not already familiar with the concept of "cepstrum"). This gives then the possiblity to add more structure and details to the main content and to make separate headlines for power cepstrum, complex cepstrum etc. This will come soon. --Mbasti01 (talk) 16:09, 5 April 2020 (UTC)
thread_title:  Improvement of the introduction section 

message: The following text is repeated in the article: 
The name cepstrum was derived by reversing the first four letters of spectrum. Operations on cepstra are labelled quefrency analysis (aka quefrency alanysis[1]), liftering, or cepstral analysis. It may be pronounced in the two ways given, the second having the advantage of avoiding confusion with kepstrum.  — Preceding unsigned comment added by Lehnekbn (talk • contribs) 11:41, 10 October 2021 (UTC)
replies: text: Fixed. 109.252.90.119 (talk) 21:45, 3 November 2021 (UTC)
thread_title:  Repeated text? 

message: Jh 105.103.225.201 (talk) 14:26, 14 December 2022 (UTC)
thread_title:  Cepstrum 

message: The second paragraph in the Applications section ("Recently, cepstrum-based deconvolution was used on surface electromyography signals [..]") reads like an ad for the referenced paper.
It is too long and detailed compared to the surrounding content and feels out of place.
And indeed, the paragraph was added by a user 'Orcioni', the same name as the second author of the paper (edit of 11:36, 20 March 2018‎; a year after the paper's publication). TomasFiers (talk) 16:07, 4 June 2024 (UTC)
thread_title:  Ad for a paper in 'Applications'