Engineers explore algorithm's capabilities in special cases 'on the unit circle

Iowa State University's Alexander Stoytchev says it's one of the "most popular and useful" algorithms around -- even though most of us have never heard of it.

But, if you've used a cell phone, browsed the internet or needed a medical image, you've what jobs can you get with a computer science degree from the fast Fourier transform (FFT).

The transform and its inverse (known as the IFFT) have been in use since 1965. For example, in your cell phone the FFT is used to analyze the signal received from the base station (or cell tower). The IFFT solves the inverse problem: it synthesizes the signal that your phone sends to the base station.

In 1969, researchers developed a more useful, generalized version of the FFT known as the chirp z-transform (CZT). But nobody had come up with a generalized version of the IFFT. It was a 50-year-old puzzle in signal processing.

That is, until last fall when two Iowa State engineers -- Stoytchev and Vladimir Sukhoy -- announced in a research paper they had come up with a closed-form solution for the inverse chirp z-transform (ICZT) and a fast algorithm for computing it. (The paper sparked a lot of interest in the signal-processing community, tallying more than 26,000 accesses since October.)

Now Stoytchev -- an associate professor of electrical and computer engineering who's also affiliated with the university's Virtual Reality Applications Center -- and Sukhoy -- a lecturer in electrical and computer engineering -- report new research results about their algorithm.