Polyphase Analysis Research Articles

Clinical case of isolation and identification of <I>Streptococcus equi subsp. Zooepidemicus</I>

Streptococci manifest their pathogenic properties by reducing the overall resistance of the organism or individual tissues.Purpose of the work: isolation, identification and study of the biological properties of isolates isolated from the foal.A pure culture was obtained, morphological, cultural and biochemical properties were studied.For the subsequent identification of streptococci to species, two api 20 Strep test systems (BIOMERIEUX, France) were used. To determine the serological group of streptococci, a latex agglutination test was used using a kit for diagnosing streptococci of groups A, B, C, D, F, and G (OXOID, UK).Laboratory methods of diagnostics for the identification of causative agents of streptococcosis and their species differentiation have been studied. Virulent Streptococcus equi subsp. zooepidemicus caused abscesses in the area of the elbow joint of the foal. Isolation of bacterial cultures was carried out by the bacteriological method. Isolated Streptococcus equi subsp. zooepidemicus had the fermentation of a number of carbohydrates: sorbitol, there was no splitting of lactose, tregolose. Streptococcus equi subsp. zooepidemicus hydrolyzed esculin, no D-ribose fermentation was noted. However, the fermentation of carbohydrates is not a stable and clear sign, therefore it is not used for differentiation and identification of streptococci.When inoculated on blood agar with 5% sheep blood after cultivation for 24 hours at 37 0C, small gray-white colonies were found, surrounded by a wide transparent zone of beta-hemolysis. Catalase test is negative.As a result, it was found that the isolated culture belongs to the species Streptococcus equi subsp. zooepidemicus belonging to group C according to Lancefield.Modern laboratory diagnostics requires an integrated approach to identification, which includes bacteriological and serological methods - polyphase analysis. When identifying streptococci, the determination of their serological group according to Lancefield is of great importance. For this purpose, a latex agglutination reaction is convenient using a kit for diagnosing streptococci of groups A, B, C, D, F and G (OXOID, UK), coagglutination "Streptotest A, B, C, D, G" (AQUAPAST).

Universal Frequency-Domain Analysis of N-Path Networks

N-path commutated capacitive networks provide a practical solution to implement highly sought on-chip high-Q filtering applications in which the use of lumped inductors is undesirable due to their significant footprints and low Q-factors. Recently, it has been also revealed that N-path networks can also exhibit other interesting functionalities, such as nonreciprocal phase-shifting and ultra-wideband true time delay, providing a path to miniaturization of various reciprocal and nonreciprocal devices. The analytical treatment of these networks, however, remains challenging, because their operation involves frequency mixing produced by the time modulation. In this article, we present a highly accurate frequency-domain approach for the analysis of N-path networks based on perturbation theory. Our method compares favorably to the state-of-the-art polyphase analysis by being much simpler mathematically, yet providing results essentially indistinguishable from numerical simulations, while offering physical insights into the N-path filter operation. We particularize the solution for the high-Q operation regime and obtain simple closed-form analytical expressions for harmonic transfer functions, scattering parameters and baseband impedance.

Characterization of major properties and aroma profile of kiwi wine co-cultured by Saccharomyces yeast (S. cerevisiae, S. bayanus, S. uvarum) and T. delbrueckii

The effect of different yeast strains on the quality of kiwi wine was investigated by polyphase determine approaches in the present research. The influence of co-culture and inoculation sequence on the quality was also explored simultaneously. Results suggested that the characteristics of the kiwi wine were affected by the metabolic characteristic of strains. The flavor content and their flavor profile of samples fermented by co-culturing of strain among species, genus, and families. When Saccharomyces bayanus (Y5 or Y6) co-cultured with Torulaspora delbrueckii Y7, the ratio of phenethyl alcohol increased, but that of octanoic acid and ethyl octanoate decreased significantly. The odor activity value (OAV) of ethyl octanoate and ethyl hexanoate was increased by co-culturing Saccharomyces with T. delbrueckii, and that of decanal and terpinen-4-ol was enhanced by co-culturing of different strains of Saccharomyces. It was an excepting process to obtain high quality of kiwi wine by co-culturing technology of yeasts, and was very effective to optimize the process by polyphase analysis approaches.

MWA tied-array processing III: Microsecond time resolution via a polyphase synthesis filter

AbstractA new high time resolution observing mode for the Murchison Widefield Array (MWA) is described, enabling full polarimetric observations with up to$30.72\,$MHz of bandwidth and a time resolution of${\sim}$$0.8\,\upmu$s. This mode makes use of a polyphase synthesis filter to ‘undo’ the polyphase analysis filter stage of the standard MWA’s Voltage Capture System observing mode. Sources of potential error in the reconstruction of the high time resolution data are identified and quantified, with the$S/N$loss induced by the back-to-back system not exceeding$-0.65\,$dB for typical noise-dominated samples. The system is further verified by observing three pulsars with known structure on microsecond timescales.

M-Channel Graph Filter Banks: Polyphase Analysis and Structures

Two channel critically sampled filter banks for signal over graph domains were first proposed for undirected bipartite graphs by Narang and Ortega. Extension to the M-channel critically sampled case for balanced M-block cyclic graphs was then proposed by Teke and Vaidynathan but the filter bank does not achieve strict perfect reconstruction (PR), only generalized PR. In this letter, we consider the more general case of filter banks on unbalanced M-block cyclic graphs where strict PR is achieved. A polyphase analysis to derive the implementation structures in the downsampled domain is presented here. The relevant system/filter matrices have interesting cyclic properties and projection operators are needed to map signals between subgraphs.

Bipartite Graph Filter Banks: Polyphase Analysis and Generalization

The work by Narang and Ortega [“Perfect reconstruction two-channel wavelet filter banks for graph structured data,” IEEE Trans. Signal Process. , vol. 60, no. 6, pp. 2786–2799, Jun. 2012], [“Compact support biorthogonal wavelet filterbanks for arbitrary undirected graphs,” IEEE Trans. Signal Process. , vol. 61, no. 19, pp. 4673–4685, Oct. 2013] laid the foundations for the two-channel critically sampled perfect reconstruction filter bank for signals defined on undirected graphs. This basic filter bank is applicable only to bipartite graphs but using the notion of separable filtering, the basic filter bank can be applied to any arbitrary undirected graphs. In this paper, several new theoretical results are presented. In particular, the proposed polyphase analysis yields filtering structures in the downsampled domain that are equivalent to those before downsampling and, thus, can be exploited for efficient implementation. These theoretical results also provide new insights that can be exploited in the design of these systems. These insights allow us to generalize these filter banks to directed graphs and to using a variety of graph base matrices, while also providing a link to the $\text{DSP}_G$ framework of Sandryhaila and Moura [“Discrete signal processing on graphs,” IEEE Trans. Signal Process. , vol. 61, no. 7, pp. 1644–1636, Apr. 2013], [“Discrete signal processing on graphs: Frequency analysis,” IEEE Trans. Signal Process. , vol. 62, no. 12, pp. 3042–3054, Jun. 2014]. Experiments show evidence that better nonlinear approximation and denoising results may be obtained by a better selection of these base matrices.

Non-maximally decimated filter bank-based single-carrier receiver: a pathway to next-generation wideband communication

We present the design of a wideband digital modem based on non-maximally decimated filter bank (NMDFB) with perfect reconstruction (PR) property. The PR-NMDFB contains an analysis filter bank (AFB) and a synthesis filter bank (SFB) whose efficient polyphase forms are named as polyphase analysis channelizer (PAC) and polyphase synthesis channelizer (PSC). The waveform being processed is the legacy square root Nyquist-shaped quadrature amplitude modulation (QAM). In contrast to orthogonal frequency division multiplexing (OFDM) systems, the shaped QAM transmission has much superior performance properties in throughput, peak-to-average power ratio (PAPR), and synchronization. We will show the PR-NMDFB is capable of efficiently performing several key tasks of a digital receiver with dramatic workload reduction. This includes digital filtering, carrier recovery, and symbol timing recovery. Moreover, the nature of NMDFB allows the signal processing to operate a significantly reduced sample rate, which is a desired characteristic for replacing current FIR implementation in wideband systems.

Time-Domain Matrix Analysis of Polyphase FIR Filters

Polyphase filter design is a common subject studied in discrete systems analysis and digital signal processing (DSP) courses. However, the classic z-domain analysis, utilizing the noble identities, gives a conclusion to the true physical structures of polyphase filters which may not be obvious to many students. The proposed time-domain analysis provides a more straightforward development of polyphase implementation of interpolation and decimation functions, and hopes to provide students with a more visual representation of the polyphase interpolation and decimation processes. Results from a student survey show that over 73% of students believe that the proposed polyphase analysis strengthened their understanding of polyphase filters, and over 71% would prefer to use the proposed method over the traditional z-domain analysis when explaining polyphase filters to others.

Polyphase analysis filter bank down-converts unequal channel bandwidths with arbitrary center frequencies

A cognitive radio (CR) receiver should be able to filter and simultaneously down convert multiple signals having arbitrary bandwidths and randomly located center frequencies. In this paper we present an efficient structure, based on polyphase filter banks, for CR receivers. Its core, an analysis channelizer, is a variant of the standard M-path polyphase down converter channelizer. It is able to perform M/2-to-1 down sampling of the input time series while it shifts, by aliasing, all the M channels to base-band. A perfect reconstruction (PR) filter is selected as low-pass prototype for avoiding energy losses during the signal processing. A post analysis block is designed for extracting, when necessary, from the base-band aliased channels, the spectra, or their fragments, belonging to different signals. A selector commutes the output ports of the post analysis block that contain spectral fragments of the same bandwidths and properly delivers them to the up converter synthesis channelizers that reassemble them. The synthesis channelizers are Pn-path polyphase up converter modified for performing 1-to-Pn/2 up sampling of the input time series. Complex frequency rotators, placed at the output of the synthesizers, compensate the frequency offsets, applied in the transmitter, that are responsible for the arbitrary center frequency positioning of the received signals. At the end of the receiver chain, arbitrary interpolators resample the base-band centered signals to obtain two samples per symbol needed for the further processing stages.

Multilocus Allele Polymorphism in Different Streptococcus Thermophilus Strains Isolated from Yoghurts

ABSTRACTTwenty-one Streptococcus thermophilus strains were isolated form homemade yoghourts obtained from different areas in Bulgaria. The isolated strains were determined by polyphase analysis including classical microbiological, biochemical, physiological, as well as molecular methods including PCR amplification with genus-specific primers and sequencing of the genes responsible for 16S ribosomal RNA. A recently proposed new method for intraspecies discrimination based on single strand DNA conformation polymorphism was applied for the first time on the Streptococcus genus representatives.

Designs and architectures of filter bank trees for spectrally efficient multi-user communications: review, modifications and extensions of wavelet packet filter bank trees

A review is presented first of the evolution of transmultiplexers since about 1966, in the context of a long progression of theoretical advances and developments leading to recent proposals to fundamentally improve OFDM type systems using principles of perfect reconstruction filter (PRF) banks. The equivalence of transmultiplexers to OFDM type multi-user systems is discussed. The desirable goals for performance and implementation of transmultiplexers or multiband, multiuser communication systems that are addressed and met in this paper using filter bank trees are set down. Then modifications and extensions are presented of the designs and architectures of wavelet packet based synthesis and analysis pairs of filter bank trees (Sablatash and Lodge in Digital Signal Process 13: 58–92, 2003) that can be used as transmultiplexers. These exhibit a number of advantages over the previous designs and address three shortcomings of the designs used to illustrate basic principles in Sablatash and Lodge (Digital Signal Process 13:58–92, 2003). The first of these is the asymmetry of the magnitude frequency responses of the multiplexer channels, which is addressed using a symmetric design for a lowpass and highpass quadrature mirror filter (QMF) pair described herein. The second is the problem of minimizing the total delay of the signal in passing through the analysis and synthesis filter banks. This is addressed using an architecture involving DFT polyphase synthesis filter banks to replace the wideband VSB filters at the roots of the two identical synthesis filter bank trees, but results in the multiplexer having fewer levels. In this way a tradeoff is effected of lower delay and complexity with fewer levels of bandwidth on demand. At the receiver matching DFT polyphase analysis filters and the other matching analysis filters are implemented. The third shortcoming is the difficulty in designing a synchronization scheme if the filters in the synthesis and analysis filter banks have non-linear phase. This is addressed by designing linear phase filters that do not affect the ISI to any significant degree for communication purposes, although exact perfect reconstruction is lost, but greatly ease and improve the design of the synchronization scheme. Relationships of this paper and its advantages over recent research studies and IEEE 802.22 standards proposals using PR filter banks for multi-user systems to greatly improve on OFDM systems are discussed.

Fast implementation of oversampled modulated filterbanks

The authors present an efficient implementation of oversampled filter banks derived from a prototype filter by modulation. Via a polyphase analysis, redundancies in the filter operations are removed. With some modifications, a very simple and efficient implementation is found, which is briefly compared to existing realisations.

Two polyphase filter architectures for MPEG audio

Polyphase subband filtering is a computational-intensive operation in MPEG audio coding. In this paper, we present two fast architectures by using a fast IDCT algorithm with and without recursive formula for polyphase analysis subband filtering. Our basic approach is to use only one adder/subtracter and one multiplier, but each has its own data bus, and a process controller is used to control the overall processing. We compare our design by using timing constraints, memory size, circuit complexities, and the number of operations. Low cost adder/subtracters and multipliers in VLSI implementation can be designed for real-time applications.

On the perfect reconstruction problem in N-band multirate maximally decimated FIR filter banks

The problem of finding N-K filters of an N-band maximally decimated FIR analysis filter bank, given K filters, so that FIR perfect reconstruction can be achieved, is considered. The perfect reconstruction condition is expressed as a requirement of unimodularity of the polyphase analysis filter matrix. Based on the theory of Euclidean division for matrix polynomials, the conditions the given transfer functions must satisfy are given, and a complete parameterization of the solution is obtained. This approach provides an interesting alternative to the method of the complementary filter in the case of N>2,K<N-1, where the latter leads to a system of nonlinear equations. Moreover, it yields the polyphase synthesis filter matrix as a byproduct. As an application, a complete characterization of all paraunitary matrices with fixed first row is derived. The problem of appropriately choosing the parameters characterizing the complementary filters to lead to filters of practical useful frequency responses is studied, and analytical solutions for K=N-1 are given. It is demonstrated, through an example, that the complementary filters found via Euclid's algorithm are not necessarily linear phase even if the given filters are. The problem of obtaining linear phase solutions of given orders is investigated for the general case (N/spl ges/2,K/spl les/N-1) and systematic ways are developed to compute such solutions in the K=N-1 and K=1 cases. It is also shown that the resulting synthesis filters are linear phase. Design examples illustrating the theory are presented.