Haldun M. Özaktas

Learn More
We propose and consolidate a definition of the discrete fractional Fourier transform that generalizes the discrete Fourier transform (DFT) in the same sense that the continuous fractional Fourier transform generalizes the continuous ordinary Fourier transform. This definition is based on a particular set of eigenvectors of the DFT matrix, which constitutes(More)
For time-invariant degradation models and stationary signals and noise, the classical Fourier domain Wiener filter, which can be implemented in O(N logN) time, gives the minimum mean-square-error estimate of the original undistorted signal. For time-varying degradations and nonstationary processes, however, the optimal linear estimate requires O(N2) time(More)
We show that there is a limit to the total number of bits per second, B, of information that can flow in a simple digital electrical interconnection that is set only by the ratio of the length " of the interconnection to the total cross-sectional dimension —A of the interconnect wiring — the “aspect ratio” of the interconnection. This limit is largely(More)
We deal with the problem of efficient and accurate digital computation of the samples of the linear canonical transform (LCT) of a function, from the samples of the original function. Two approaches are presented and compared. The first is based on decomposition of the LCT into chirp multiplication, Fourier transformation, and scaling operations. The second(More)
We are concerned with the problem of optimally measuring an accessible signal under a total cost constraint, in order to estimate a signal which is not directly accessible. An important aspect of our formulation is the inclusion of a measurement device model where each device has a cost depending on the number of amplitude levels that the device can(More)
Filtering in a single time domain or in a single frequency domain has recently been generalized to filtering in a single fractional Fourier domain. In this correspondence, we further generalize this to repeated filtering in consecutive fractional Fourier domains and discuss its applications to signal restoration through an illustrative example.
We present much briefer and more direct and transparent derivations of some sampling and series expansion relations for fractional Fourier and other transforms. In addition to the fractional Fourier transform, the method can also be applied to the Fresnel, Hartley, and scale transform and other relatives of the Fourier transform. ? 2003 Published by(More)
It is customary to define the time-frequency plane such that time and frequency are mutually orthogonal coordinates. Representations of a signal in these domains are related by the Fourier transform. We consider a continuum of “fractional” domains making arbitrary angles with the time and frequency domains. Representations in these domains are related by(More)
Interdisciplinary courses on science, engineering and society have been successfully established in two cases, at Bilkent University, Ankara, Turkey, and at the University of Hamburg, Germany. In both cases there were institutional and perceptual barriers that had to be overcome in the primarily disciplinary departments. The ingredients of success included(More)