{"title":"Some remarks on instantaneous amplitude and frequency of signals","authors":"B. Picinbono","doi":"10.1109/TFSA.1998.721419","DOIUrl":"https://doi.org/10.1109/TFSA.1998.721419","url":null,"abstract":"The most common way to define instantaneous amplitude, phase and frequency of a real signal is to use its analytic signal. One of the main advantages of this procedure is that it establishes a one-to-one relationship between any real signal and the pair of functions defining its instantaneous amplitude and phase. However, there are some problems in its physical interpretation but it is shown that for narrow-band signals the analytical signal is well related to some physical procedures allowing the measurements of amplitude and frequency. As any analytical signal is a very specific function, any arbitrary pair of functions cannot be considered as the amplitude and phase of a real signal. This point is especially discussed in the case of phase signals, which means signals with constant instantaneous amplitude. The phase must satisfy very specific conditions related to the theory of Blaschke functions and analyzed in the regular as well as in the singular cases. These results are applied to hyperbolic and parabolic chirp signals. Hyperbolic signals are true phase signals corresponding to the singular case. On the other hand parabolic signals, often called signals with instantaneous frequency varying linearly in time, are not phase signals and their amplitude is not constant. This point is analyzed in detail and the structure of their amplitude and phase is explicitly calculated. Various calculations allow the evaluation of the errors appearing when assuming that these signals are true phase signals. Some extensions to other cases of chirp signals are discussed.","PeriodicalId":395542,"journal":{"name":"Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis (Cat. No.98TH8380)","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127037681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Sekihara, S. Nagarajan, D. Poeppel, Y. Miyashita
{"title":"Estimating neural sources from each time-frequency component of magnetoencephalographic data","authors":"K. Sekihara, S. Nagarajan, D. Poeppel, Y. Miyashita","doi":"10.1109/TFSA.1998.721363","DOIUrl":"https://doi.org/10.1109/TFSA.1998.721363","url":null,"abstract":"We have developed a method that incorporates the time-frequency characteristics of neural sources into magnetoencephalographic (MEG) source estimation. This method calculates a time-frequency matrix in which diagonal and off-diagonal terms are the auto- and cross-time-frequency distributions of multi-channel MEG recordings, respectively. The method averages this matrix over the time-frequency region of interest. The locations of neural sources are then estimated by checking the orthogonality between the noise subspace of this averaged matrix and the sensor lead field. The method therefore allows neural sources to be estimated from any time-frequency component of measured data. We applied the method to estimating sources for gamma-band (frequency range between 30 and 100 Hz) auditory activity, and the results demonstrating the method's effectiveness were obtained.","PeriodicalId":395542,"journal":{"name":"Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis (Cat. No.98TH8380)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127236986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A flexible structure for wavelet packet-based subband adaptive equalization","authors":"N. González-Prelcic, F. P. González, A. Gonzalez","doi":"10.1109/TFSA.1998.721440","DOIUrl":"https://doi.org/10.1109/TFSA.1998.721440","url":null,"abstract":"We propose a new technique for subband adaptive equalization of highly correlated time-varying signals. The main contribution of the work consists of a tree selection algorithm that leads, for a fixed number of bands, to a quasi optimum convergence rate of the adaptive filters in the different subbands. We also provide a detailed analysis of the behaviour of the subband scheme and verify experimentally the efficiency of the proposed scheme; moreover, we compare its overall performance to that of NLMS and RLS in the time domain.","PeriodicalId":395542,"journal":{"name":"Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis (Cat. No.98TH8380)","volume":"138 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121634087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ultrasonic image processing for tendon injury evaluation","authors":"Nam-Deuk Kim, L. Booth, V. Amin, J. Lim, S. Udpa","doi":"10.1109/TFSA.1998.721406","DOIUrl":"https://doi.org/10.1109/TFSA.1998.721406","url":null,"abstract":"Image texture analysis techniques have been applied for evaluating tendon injuries in racehorses. Ultrasound images from superficial and deep digital flexor tendons have been characterized and a measure for quantifying injury grade has been proposed. Wavelet-based texture segmentation and classification algorithms have been developed for quantification of the injury grades. Discrete wavelet packet frames and standard discrete wavelet transforms are used to measure the percentage of the tendon injury and tendon fiber alignment, respectively. Results demonstrating the effectiveness of the approach in predicting the percentage of the tendon injury as well as the degree of tendon fiber alignment are presented.","PeriodicalId":395542,"journal":{"name":"Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis (Cat. No.98TH8380)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124793645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Modified Zak transform for the quincunx-type Gabor lattice","authors":"M. J. Bastiaans, A. van Leest","doi":"10.1109/TFSA.1998.721389","DOIUrl":"https://doi.org/10.1109/TFSA.1998.721389","url":null,"abstract":"Gabor's (1946) signal expansion and the Gabor transform are formulated on a quincunx lattice instead of on the traditional rectangular lattice; the representation of the quincunx lattice is based on the rectangular lattice via either a shear operation or a rotation operation. A modified Zak (1972) transformation is defined with the help of which Gabor's signal expansion and the Gabor transform can be brought into product forms that are identical to the ones that are well known for the rectangular sampling geometry.","PeriodicalId":395542,"journal":{"name":"Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis (Cat. No.98TH8380)","volume":"670 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122117036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Signal reconstruction from the reassigned spectrogram","authors":"D. M. Lopes, P. White","doi":"10.1109/TFSA.1998.721351","DOIUrl":"https://doi.org/10.1109/TFSA.1998.721351","url":null,"abstract":"The problem of recovering the original time series from the time-frequency representation (TFR) created by the reassigned spectrogram is considered. It is shown that the original time series can be recovered (to within a multiplicative constant) given certain conditions on the overlap used to create the original short-time Fourier transform (ST-FT) upon which the reassigned spectrogram is based. The paper begins by recovering the phase of the ST-FT from the reassigned spectrogram, then proceeds to describe a method of reconstructing the original time series from knowledge of the phase of the ST-FT alone. The paper concludes by giving some examples of signals recovered from the reassigned spectrogram.","PeriodicalId":395542,"journal":{"name":"Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis (Cat. No.98TH8380)","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123203792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Enhanced signatures for event classification: the projector approach","authors":"V. Venkatachalam, J. Aravena","doi":"10.1109/TFSA.1998.721469","DOIUrl":"https://doi.org/10.1109/TFSA.1998.721469","url":null,"abstract":"The classification of nonstationary signals of unknown duration is of great importance in areas like oil exploration, moving target detection, and pattern recognition. In an earlier work, we provided a solution to this problem, based on the wavelet transform, by defining representations called pseudo power signatures for signal classes which were independent of signal length, and proposed a simple approach using the singular value decomposition to generate these signatures. This paper offers a new approach resulting in more discriminating signatures. The enhanced signatures are obtained by solving a nonlinear minimization problem involving an inverse projection. The problem formulation, solution procedure, and computational algorithm are presented in this work. The efficacy of the projection signatures in separating highly correlated signal classes is demonstrated through a simulation example.","PeriodicalId":395542,"journal":{"name":"Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis (Cat. No.98TH8380)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126459449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Evolutionary spectrum estimation by positivity constrained deconvolution","authors":"M. K. Emresoy, A. El-Jaroudi","doi":"10.1109/TFSA.1998.721513","DOIUrl":"https://doi.org/10.1109/TFSA.1998.721513","url":null,"abstract":"A deconvolution technique to estimate the evolutionary spectrum (ES) of nonstationary signals by deconvolving the blurring effects of the kernel function from bilinear time-frequency distributions (TFD) is presented. The resulting ES has desirable properties such as positivity, higher resolution, higher concentration in time-frequency. The proposed algorithm is computationally more efficient compared to the recently proposed entropy based deconvolution method. Unlike the entropy method the new algorithm can be adapted to deconvolve TFDs other than the spectrogram.","PeriodicalId":395542,"journal":{"name":"Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis (Cat. No.98TH8380)","volume":"279 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116589053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Kutay, H. Ozaktas, M. F. Erden, H. Ozaktas, O. Arikan
{"title":"Solution and cost analysis of general multi-channel and multi-stage filtering circuits","authors":"M. Kutay, H. Ozaktas, M. F. Erden, H. Ozaktas, O. Arikan","doi":"10.1109/TFSA.1998.721466","DOIUrl":"https://doi.org/10.1109/TFSA.1998.721466","url":null,"abstract":"The fractional Fourier domain multi-channel and multi-stage filtering configurations that have been previously proposed enable us to obtain either exact realizations or useful approximations of linear systems or matrix-vector products in many different applications. We discuss the solution and cost analysis for these configurations. It is shown that the problem can be reduced to a least squares problem which can be solved with fast iterative techniques.","PeriodicalId":395542,"journal":{"name":"Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis (Cat. No.98TH8380)","volume":"40 16","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120855595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A relation between the Cauchy wavelets and the step-up/down operator of a kind of orthogonal wavepacket system","authors":"F. Sakaguchi","doi":"10.1109/TFSA.1998.721379","DOIUrl":"https://doi.org/10.1109/TFSA.1998.721379","url":null,"abstract":"It is well known that the over-complete Cauchy wavelet system with continuous parameters is the eigenfunction system of the operator T+kJ (T:multiplication by t, J:integral op.). This is quite parallel to the well-known relation between the coherent state system and the boson annihilation operator used in quantum mechanics, in which the annihilation operator is the step-down operator of the number states. In this paper, for the Cauchy wavelet system, we show a similar relation to this on the step-up/down operator of a kind of orthogonal function system. The operator T+kJ itself is not the step-down operator but a kind of rational function of this operator,and is the step-down operator of a kind of orthogonal wavepacket system which is the eigenfunction system of the analogue of 'number' operator.","PeriodicalId":395542,"journal":{"name":"Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis (Cat. No.98TH8380)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134020319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}