A Spectral Factorization Approach to Pseudo-QMF Design

A new approach to the design of M-channel pseudoquadrature-mirror-filter (QMF) banks is presented. In this approach, the prototype filter is obtained as a spectral factor of a 2Mth band filter. This completely eliminates the need for optimization whereas in conventional pseudo-QMF designs, the main computational effort is in optimization of the prototype. As in the conventional approach, the aliasing cancellation (AC) constraint ensures that all the significant aliasing terms are canceled. The overall transfer function T(z) of the analysis/synthesis system has a linear phase and an approximately “flat” magnitude response in the frequency region ε ≤ ω ≤ (π - ε), where ε depends on the transition bandwidth of the prototype and 0 < ε < (π/2M). Three design examples are included

QUANTITATIVE ANALYSIS OF BIOACTIVE COMPOUNDS FROM TAGETES ERECTA (LINN.)

Objectives: This study investigates the quantitative analysis of the major phytoconstituents of Tagetes erecta (Linn.) and proves their therapeuticvalue as medicines in both leaf and flower extracts.Methods: The various bioactive compounds were quantitatively analyzed as per standard methods.Results: The present study registered carbohydrates, coumarine, alkaloids, and quinone which are of medicinal importance. During the study, quinonerecorded the highest amount of phytocomponents in both the leaf and flower samples.Conclusion: The significant result of the present study revealed that the flower extract exhibited more amounts of phytochemicals than the others,and this could be exploded for potential drug development in future.Keywords: Phytoconstituents, Coumarine, Alkaloids, Quinone, Extraction, Solvents

On arbitrary-level IIR and FIR filters

A recently published method for designing IIR (infinite-impulse-response) digital filters with multilevel magnitude responses is reinterpreted from a different viewpoint. On the basis of this interpretation, techniques for extending these results to the case of finite-impulse-response (FIR) filters are developed. An advantage of the authors' method is that, when the arbitrary-level filter is implemented, its power-complementary filter, which may be required in specific applications, is obtained simultaneously. Also, by means of a tuning factor (a parameter of the scaling matrix), it is possible to generate a whole family of arbitrary-level filters

Cosine-modulated FIR filter banks satisfying perfect reconstruction

The authors obtain a necessary and sufficient condition on the 2M (M = number of channels) polyphase components of a linear-phase prototype filter of length N = 2mM (where m = an arbitrary positive integer), such that the polyphase component matrix of the modulated filter is lossless. The losslessness of the polyphase component matrix, in turn, is sufficient to ensure that the analysis/synthesis system satisfies perfect reconstruction (PR). Using this result, a novel design procedure is presented based on the two-channel lossless lattice. This enables the design of a large class of FIR (finite impulse response)-PR filter banks, and includes the N = 2M case. It is shown that this approach requires fewer parameters to be optimized than in the pseudo-QMF (quadrature mirror filter) designs and in the lossless lattice based PR-QMF designs (for equal length filters in the three designs). This advantage becomes significant when designing long filters for large M. The design procedure and its other advantages are described in detail. Design examples and comparisons are included

Theory and design of perfect reconstruction transmultiplexers and their relation to perfect reconstruction QMF banks

The theory of transmultiplexers involves the design of filters for interconversion between Time Domain Multiplexing (TDM) and Frequency Division Multiplexing (FDM), such that the undesirable Crosstalk is minimized. In TDM → FDM → TDM conversion, the perfect reconstruction trans-multiplexer (PR-TMUX) achieves complete Crosstalk Cancellation (CC) and is distortion-free. In this paper, we present an analysis of the PR-TMUX based on the polyphase component matrices of the filter banks used in TDM → FDM and FDM → TDM conversion respectively. Using that, a necessary and sufficient condition for complete CC is obtained. The close relation between PR-TMUX filters and PR-QMF banks is used to obtain a direct design procedure for PR-TMUX filters

Some results in the theory of crosstalk-free transmultiplexers

The crosstalk-free transmultiplexer (CF-TMUX) focuses on crosstalk cancellation (CC) rather than on suppressing it. The authors present an analysis of the CF-TMUX based on the polyphase component matrices of the filter banks used in TDM→FDM and FDM→TDM conversions, respectively. Thus a necessary and sufficient condition for complete CC is obtained. It is shown that the filters for a CF-TMUX are the same as the filters for a 1-skewed alias free QMF bank. In addition, if the QMF bank satisfies the perfect reconstruction (PR) property, then the TMUX also satisfies PR. The relation between CF-TMUX filters and alias-free QMF banks is used to obtain a direct design procedure for CF-TMUX filters (both FIR and IIR). It is also shown that approximately crosstalk-free TMUX filters can be obtained from any approximately alias-free QMC bank. Design examples and comparison tables are included

Relationship Between Process Management Practices And Corporate Sustainable Development In The Malaysian Manufacturing Corporations: The Moderating Effects Of Knowledge Management Capabilities And Environmental Initiatives

Over the past two decades, domestic competition and globalization has threatened the growth, profitability and the very survival of many corporations in general. Various studies have shown that corporations need to be concerned with their process management practices to overcome sustainability issues. Thus, process management practices has emerged as an approach for continuous improvement and sustainable development in a systematic manner. Although the significance of process management practices highlights sustainability issues, improves performance and increases corporation market value, little is known about process management and their vast potentials towards corporate sustainable development in the Malaysian context. This study therefore investigates the existence of process management practices and corporate sustainable development in Malaysia, and the moderating effects of knowledge management capabilities and environmental initiatives on the relationship between process management practices and corporate sustainable development. To attain the objectives, this study utilized a survey method to acquire the required information from manufacturing corporations. The survey was carried out among ISO 9001 certified corporations in Malaysia. A total of 213 usable questionnaires were received from the respondents