H. Renganathan

Bio: H. Renganathan is an academic researcher from Indian Institutes of Technology. The author has contributed to research in topics: Fourier transform & Discrete Fourier transform. The author has an hindex of 1, co-authored 1 publications receiving 2 citations.

Optimum binary windows for discrete Fourier transforms

Abstract: A class of windows, called binary windows, for the frequency-domain implementation of the discrete Fourier transform is proposed. While the conventional time-domain windowing requires N/2 stored values of the data window and N multiplications, the binary windows do not require multiplications or stored constants; rather, they are replaced by shift and add operations. Typical hardware structures are presented for efficient implementation of the binary windows.

A technique for realizing linear phase IIR filters

Abstract: A real-time IIR filter structure is presented that possesses exact phase linearity with 10 approximately 1000 times fewer general multiplies than conventional FIR filters of similar performance and better magnitude characteristics than equiripple or maximally flat group delay IIR filters. This structure is based on a technique using local time reversal and single pass sectioned convolution methods to realized a real-time recursive implementation of the noncausal transfer function H(z/sup -1/). The time reversed section technique used to realize exactly linear phase IIR filters is described. The effects of finite section length on the sectional convolution are analyzed. A simulation methodology is developed to address the special requirements of simulating a time reversed section filter. A design example is presented, with computer simulation to illustrate performance, in terms of overall magnitude response and phase linearity, as a function of finite section length. Nine example filter specifications are used to compare the performance and complexity of the time reversed section technique to those of a direct FIR implementation. >

Asymmetric Windows and their Application in Frequency Estimation

Abstract: Classic windows have constant time delay and linear phase because of the symmetry and the time shift causality-imposed in the time domain. And thus, all such windows have the same spectral phase response. Removal of the symmetry constraint on a classic window can result in a variable phase response and in an alterable time delay. In essence the time delay becomes shorter will bring about a lot of benefits in speech coding. Some asymmetric windows with better magnitude response also can lead to a better recognition performance if the result is relatively insensitive to phase distortion. However, it is surprising that so little attention has been paid to the asymmetric windows in past literature; and never in past history has this issue been systematically or comprehensively studied. As a result, several methods to obtain the asymmetric windows are being presented in this paper. The asymmetric windows are displayed and compared with the classic windows, concerning both in time and frequency domains. Some ne...