We study local deformations of time-frequency and timescale representations, in the framework of the so-called reassignment methods, which aim at deblurringg time-frequency representations. We focus on deformations generated by appropriate vector elds deened on time-frequency or time scale plane, and constructed on the basis of geometric and group-theoretical arguments. Such vector elds may be ...

ASTRONOMY AND ASTROPHYSICS High precision difference astrometry applied to the triplet of S5 radio sources B1803+784/Q1928+738/B2007+777 Abstract. We determined the separations of the radio sources in the triangle formed by the BL Lac objects 1803+784 and 2007+777, and the QSO 1928+738 from in-tercontinental interferometric observations carried out in November 1991 at the frequencies of 2.3 and...

In this paper, we propose a method for robust detection of the vowel onset points (VOPs) from noisy speech. The proposed VOP detection method exploits the spectral energy at formant frequencies of the speech segments present in glottal closure region. In this work, formants are extracted by using group delay function, and glottal closure instants are extracted by using zero frequency filter bas...

One of the key issues in practical speech recognition is to achieve robust gender identification. Most conventional gender identification approaches use relevant features derived from the magnitude spectrum. In this paper, we propose a novel gender identification method using a group delay function (GDF). Based on the statistical analysis of the GDF, it is found that the GDF is an effective fea...

This paper demonstrates the robustness of group-delay based features for speech processing. An analysis of group delay functions is presented which show that these features retain formant structure even in noise. Furthermore, a speaker verification task performed on the NIST 2003 database show lesser error rates, when compared with the traditional MFCC features. We also mention about using feat...

The effect of delay and reflectivity ripples of dispersion compensating fibre gratings on systems operated at 10 Gb/s over 100 km of standard single-mode fibre is investigated for partial or total dispersion compensation .

In this paper, we investigate a new method for extracting useful information from the group delay spectrum of speech. The group delay spectrum is often poorly behaved and noisy. In the literature, various methods have been proposed to address this problem. However, to make the group delay a more tractable function, these methods have typically relied upon some modification of the underlying spe...

In this paper, a novel multitaper modified group delay function-based representation for speech signals is proposed. With a set of phoneme-based experiments, it is shown that the proposed method performs better that an existing multitaper magnitude (MT-MAG) estimation technique, in terms of variance and MSE, both in spectraland cepstral-domains. In particular, the performance of MT-MOGDF is fou...

Measurements of the phase delay of the current and force on a ring floated on a commonly available Thomson’s jumping ring apparatus were performed for phase angles from 12° to 88°. The force and phase data show excellent agreement with a linear inductive model. We find that the demonstration, as usually performed with large highly conducting rings, operates in the inductance-dominated regime at...

We propose and demonstrate a novel method to improve the accuracy of measurements of group delays using the conventional phase-shift technique. In particular, the method allows for accurate reconstruction of the actual group delay when a high modulation frequency is employed to increase the timing resolution. The method is based on postprocessing of the measured data in a deconvolution operatio...