Discrete time Fourier and related transforms
Also, chirplets, z-transforms, chromatic derivatives…
October 17, 2019 — October 17, 2019
Care and feeding of Discrete Fourier transforms (DTFT), especially Fast Fourier Transforms, and other operators on discrete time series. Complexity results, timings, algorithms, properties. These are useful in a vast number of applications, such as filter design, time series analysis, various nifty optimisations of other algorithms etc.
1 Chirp z-transform
Chirplets, one-sided discrete Laplace transform related to damped sinusoid representation. (Bluestein 1970; Rabiner, Schafer, and Rader 1969)
A recent publication (Sukhoy and Stoytchev 2019) shows that these are as tractable as FFTs to invert, which is to say, very. I will read the paper and see if that is as useful to me as it seems like it might be. (The paper has a lot of elementary proofreading errors, which is a bad start.)
🏗
2 Windowing the DTFT
(Harris 1978; Cooley, Lewis, and Welch 1970; Rafii 2018)
🏗
3 Chromatic derivatives
(Narasimha, Ignjatovic, and Vaidyanathan 2002; Aleksandar Ignjatovic 2007; A. Ignjatovic 2009; Aleksandar Ignjatovic, Wijenayake, and Keller 2018b, 2019, 2018b)
🏗