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Characterization of electromagnetic field sensors requires that the behaviour of each sensor is investigated over the whole functional space, i.e., the range in which the device is expected to work. In most cases, for the sake of time reduction, experiments are run only over a subset of the functional space. The reduced extension of the experimental space limits the knowledge of the actual behaviour of the probe represented by the calibration factor K. Linear regression is a common technique to represent measurement data, but it is generally not applied to sensor calibration. Furthermore, no comparative study of experimental plans differing in the number and location of experimental points has ever been carried out nor has a methodology to determine the optimal degree of the regression polynomial been outlined. This paper compares the error variance between experimental points and fitted curve obtained using different experimental plans and regression polynomials.

Noise signals are often encountered in several science and engineering fields. They can be originated by a lot of different mechanisms, some of which are still not sufficiently understood. Since reliability and performance of many systems depend on their noise sensitivity and noise rejection capability, suitable noise sources are required to lead appropriate tests to investigate the behavior of the same systems in the presence of noise. At present, only white noise sources are available on the market. Technicians that need to generate colored noise could use arbitrary waveform generators as noise sources; but, they will barely find application notes that support them in this challenging task. This work presents tutorial notes related to the simulation of colored noise, in particular of composite-power-law noise, and proposes an analog generator that exploits an arbitrary waveform generator as noise source.

Cellular heterogeneity is a hallmark characteristic of ostensibly similar cell populations occurring during neural and glial development, and during tumorigenesis and tumor progression. For the latter case, large collections of formalin-fixed paraffin embedded (FFPE) clinical specimens are a valuable resource for evaluating gene expression across large study cohorts. Many of these patient samples consist of serial tumor sections each stained for a single antigen by chromogenic immunohistochemistry (IHC), as is standard clinical pathology practice. Quantifying multiple tumor related antigens in the context of GBM tissue is an essential step towards understanding the fundamental biology of these tumors as well as developing novel targeted therapies. Towards this end, we have developed methods for combining semi-quantitative analysis of IHC processed tumor sections with regional annotation by a clinical pathologist. This has allowed us to consider patterns of antigen co-expression as well as spatial relationships with tumor structures and physiological status. We will present our observations on expression of tumor-associated antigens IL13Rα2, HER2 and EGFR, and associations with proliferation as indicated by Ki67 expression and the vasculature as marked by the endothelial cell marker CD34.

The dismal prognosis of late stage, unresectable pancreatic adenocarcinoma (PDAC) patients has prompted the search for novel chemotherapeutic agents. However, PDAC tumors are encapsulated by a remarkable fibrotic extracellular matrix (ECM), termed desmoplasia that prevents efficient intratumoral delivery of therapeutics. Thus, current PDAC therapies such as gemcitabine, Abraxane, erlotinib, and folfirinox must be given at elevated doses resulting in systemic toxicity with only marginal improvement in patient survival. The increased deposition of ECM components, such as hyaluronan (HA), surrounding and internal to the tumor mass serves as the ideal target for reducing desmoplasia and improving drug delivery. PEGPH20 is a pegylated hyaluronidase developed by Halozyme Therapeutics that depletes HA and increases vascular permeability in spontaneous murine PDAC tumors. Data from a Phase 1b trial indicates a clinical benefit of using PEGPH20 with gemcitabine in patients with high levels of PDAC-associated HA. In the present work, we tested a unique combination of PEGPH20 with a Salmonella-based therapeutic, shIDO-ST, which expresses an inhibitory RNA (RNAi) that degrades indoleamine 2,3-dioxygenase (IDO) mRNA. We observed striking regression in 100% of mice (N=4/group) with our unique therapeutic combination leading to elimination of orthotopically transplanted PDAC tumors, whereas combinations of gemcitabine and Abraxane marginally stabilized tumor growth (p Supported by R21 CA174306, the Tim Nesvig Foundation, and Halozyme Therapeutics Citation Format: Edwin R. Manuel, Melanie G. Lampa, Joseph Kim, Vincent Chung, Massimo D'Apuzzo, Curtis B. Thompson, Zhongdong Huang, Daniel C. Maneval, Don J. Diamond. Control of PDAC tumor progression by RNA interference targeting indoleamine 2,3-dioxygenase using salmonella as a delivery vehicle facilitated by PEGPH20. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr A97.

e11610 Background: The addition of pertuzumab, to trastuzumab-based chemotherapy is currently considered first-line therapy for locally advanced and metastatic disease HER2 positive breast cancer a...

Human neural stem cells (NSCs) are serving as vehicles for targeted delivery of cytosine deaminase/5-flucytosine enzyme/prodrug therapy to recurrent glioma patients in first in human Phase 1 clinical trials (IND 14041). The initial safety/feasibility clinical study demonstrated safety, non-tumorigenicity, non-immunogenicity with 1 round of treatment, and proof of concept for localized conversion of 5-Flucytosine to the active chemotherapeutic agent, 5-Fluorouracil. We have now developed a second generation NSC brain tumor therapy, engineering NSCs to secrete a modified human carboxylesterase (hCE1m6) that converts irinotecan (IRN) to the potent topoisomerase inhibitor SN-38. Biodistribution, efficacy, and safety/toxicity studies have been completed and an Investigational New Drug application has been filed with the Food and Drug Administration (IND 16265).Early studies on the CE-expressing human NSCs was described in Metz, et al., Stem Cells Transl Med. 2013 Dec;2(12):983), demonstrating tumor tropism in orthotopic human glioma models and tumor localized conversion of IRN to SN-38 in a time-dependent manner. The current preclinical studies show in vivo biodistribution of varying doses of intracranially delivered CE-NSCs and optimization of a clinically relevant adult IRN treatment regimen based on pharmacokinetic and long term survival studies. These studies demonstrated a statistically significant increase in long-term survival distributions with the addition of CE-NSCs + IRN as compared to IRN alone (see figure). These data, together with our preclinical safety/toxicity data, support clinical translation of this schema to phase I clinical trials for patients with recurrent glioma. View Large Image | Download PowerPoint Slide

The reliability and performance of many systems mostly depend of their noise rejection capability. The behavior of systems that are prone to noise is therefore investigated since the early production stage, as well as routinely during periodical maintenance actions. Actually, there are very few noise sources available on the market, the majority of which is capable of generating only noise characterized by a uniform power spectral density in a limited bandwidth; generators capable of producing colored noise are instead very rare. In theory, arbitrary waveform generators could be deployed and suitably programmed to serve as noise sources. But, the technicians charged of test and measurement assignments will barely find application notes that support them in stepping from theory to practice.This work presents tutorial notes related to the simulation of colored noise, and proposes an analog generator that exploits an arbitrary waveform generator as noise source. The proposed generator is capable of producing noise signals characterized by arbitrary power spectral densities.

This paper details the case of a 64-year-old woman who presented to the psychiatry service with worsening mood in the context of a diagnosis of obsessive-compulsive disorder (OCD). On further examination she was found to have clinical findings consistent with frontotemporal lobar degeneration of the non-fluent progressive aphasia subtype. At post-mortem she was found to have progressive supranuclear palsy. We argue, in retrospect, that her OCD was likely prodromal to the development of her dementia. This case highlights the fact that frontotemporal lobar degeneration/progressive supranuclear palsy (FTLD/PSP) and other "tauopathies" represent a complex group of neurodegenerative disorders that may masquerade for many years as refractory psychiatric disorders.

The paper is focused on monitoring operations performed in power systems. The attention is paid to slow variations characterizing frequency and amplitude parameters of sinusoidal components. A suitable digital signal processing method aimed at estimating frequency and amplitude variations characterizing both the fundamental component as well as single harmonics and interharmonics contained in distorted waveforms is presented. To track time-varying frequency the method first detects the phase deviations of the sinusoidal input with respect to the expected linear trend, and then evaluates the time derivative. In parallel, to track amplitude fluctuations the method takes the square root of the quadratic summation of input sinusoidal projections on two orthogonal references. Distributed filtering operations grant the capability of distinguishing and separately analyzing close-to-each-other components; phase unwrapping allows components affected by significant frequency variations to be tracked.

Modeling of digital-to-analogue converters (DAC's) and identification of their chief parameters is here dealt with. The attention is focused on a well-known static model accounting for linearity and intermodulation errors, which are of major concern for DAC functional characterization as well as troubleshooting. Estimation of model's parameters is currently carried out through linear transformations, the application of which is not practical for high resolution DAC's; also, usable relations for assessing the uncertainty on estimated parameters are not given. The authors introduce a new parameter in the model with the aim of proposing an alternative formulation. Complete identification of the DAC under test can thus be pursued through a new fast transformation, characterized by reduced computational burden and suitable for fully in-place implementation

Power measurement in digital wireless communication systems often suffers from poor repeatability, usually accompanied by low accuracy. Trying to give a proper answer to these problems, the use of parametric spectral estimators is investigated in the paper. A new method for power measurement is, in particular, proposed, which exploits Burg's solution to attain an estimation of the power spectral density (PSD) of the radiofrequency signal, suitably downconverted, and then applies straightforward measurement algorithms to the estimated PSD, in order to evaluate the quantities of interest. The performance of the method is assessed through a number of experiments, carried out on both laboratory and actual signals. Achieved results confirm the efficacy and reliability of the method in mitigating the aforementioned problems. Moreover, a comparison of the method's performance with that offered by an alternative solution, already proposed by the authors and based on nonparametric PSD estimation, shows that the new method allows for a significant reduction of measurement time, while exhibiting the same repeatability

Early events involved in the pathogenesis of colorectal cancer include mutations in the Adenomatous Polyposis Coli tumor-suppressor gene and oncogenic KRAS mutations. Later events include deletions on chromosome 18q, which are observed in a high proportion of colorectal cancers. However, the important tumor suppressor genes targeted by these deletions have not been fully defined. A previous study found Cables is located on human chromosome 18q11-12. Loss of Cables expression as determined by immunohistochemical staining (IHC) occurred in 60-70% of sporadic colorectal cancers that were usually correlated to loss of heterozygosity at 18q. To determine if Cables is an important target for the chromosome 18q deletions, the susceptibility of Cables-/- mice to develop colon tumors was studied. A well characterized colonic carcinogen, 1,2-dimethylhydrazine (DMH) was used as a tumor initiator. Cables-/- mice (n = 25) and the Cables+/+ littermates (n = 25) were treated with subcutaneous DMH injections over 20 weeks to initiate tumorigenesis. The median survival after DMH injections was significantly shorter for the Cables-/- mice compared to Cables+/+ littermates. The total number of colorectal tumors that developed in the Cables-/- mice was 46 tumors versus 21 tumors. The increased numbers of colorectal tumors, as well as shorter survival of the Cables-/- mice provides compelling evidence that Cables could play an important role in the pathogenesis and progression of colon cancer in mice. These data coupled with previous observations support the hypothesis that Cables is a relevant target of the chromosome 18q deletions frequently seen in human colorectal cancer.

The rapid growth of third generation (3G) telecommunications systems has created the need for getting new test equipment as well as getting measurement techniques up and running in a very short time. Trying to satisfy this exigency, a new measurement method for testing 3G transmitters is proposed here. Thanks to the use of time-frequency distributions, the method provides a unified approach for carrying out, automatically and in a very straightforward manner, most measurements needed to fulfill the aforementioned task. After a brief outline of 3G technology basics, some details concerning transmitter tests are given. The fundamental steps of the proposed method are then described with references to a clarifying example, also highlighting advantages with respect to other measurement solutions. At the end, the performance of the method is assessed by means of several experiments on both simulated and emulated signals.

A digital method for testing and qualification of GSM equipment is presented. The method, based on the use of time-frequency representations, shows itself suitable to carry out most measurements needed for the characterization both of base stations and mobiles. It is possible to avoid the employment of different instruments, complex procedures, and qualified users. Some aspects regarding GSM measurements are first presented in order to clearly describe the operative stages of the method. Then, its performance is assessed by analyzing reference signals. Experimental results obtained from the application of the method to actual GSM signals are finally given.

A method, based on echo detection by means of the Wavelet Transform, for measuring unknown thicknesses of multilayer structures is presented. Brief theoretical considerations underlying the method are first reported. They highlight the high performance shown by the Wavelet Transform as a powerful analysis tool of echoes in noisy environment. Then, a suitable operative procedure, for the method validation when a standard multilayer structure is not available, is set up and discussed. To this aim tests on (i) simulated signals and (ii) actual signals back from known thicknesses are carried out. Finally, experimental results obtained by the measurement method application to unknown thicknesses referred to the echo-ophthalmic field, are also reported.

The paper deals with a new method for automatically detecting and classifying transient signals. The method is based on wavelet networks which combine the aptitude of the wavelet transform in analyzing nonstationary signals with the classification capabilities of artificial neural networks. A detailed description of the wavelet network structure is first given. Then, the fundamental stages of the proposed method are presented. The first results obtained from the application of the method to transients typical of a significant field are finally shown.

Measurement of phase and frequency errors, affecting the transmitted signal in digitally encoded cellular systems, is discussed here. To this aim, a new, cost-effective technique, particularly suitable in time domain multiple access (TDMA) systems, is proposed. In contrast to other measurement methods or instruments, the proposed technique gains burst synchronization on the analyzed signal through digital signal-processing, thus avoiding the need of sophisticated and expensive analog triggering solutions. Only a general-purpose data acquisition system is, in fact, required to capture a proper time window of the transmitted signal, preliminarily down-converted to intermediate frequency. Furthermore, in the same way as other methods or instruments, phase and frequency errors are evaluated according to a standard digital signal-processing procedure, which applies both for the actual and reference phase trajectory of the transmitted signal. The technique makes both trajectories available just at the end of the aforementioned burst synchronization stage, thus also optimizing the computational burden.

The poor prognosis for patients with malignant glioma (MG) is largely attributable to invasive therapy-resistant malignant cells responsible for tumor recurrence. Adoptive immunotherapy with T cells genetically modified to express chimeric antigen receptors (CARs) may be an effective and safe strategy for reducing disease recurrence. Our group has developed a CAR T cell immunotherapy targeting IL13Rα2, a receptor over-expressed by a high percentage of MGs. In two previous phase I clinical trials evaluating first-generation IL13Rα2-CAR T cells, we demonstrated the feasibility of this approach, showing an absence of serious therapy-related side-effects and evidence for transient anti-glioma responses. Building on this experience, we have now developed an optimized CAR T cell product incorporating enhancements in CAR design and T cell engineering, which improve T cell persistence and antitumor potency. These include a second-generation CAR containing the 41BB (CD137) costimulatory signaling domain (IL13BBζ-CAR), and a manufacturing strategy using an enriched central memory T cell (Tcm) population for genetic engineering. In orthotopic IL13Rα2+ MG mouse models, single injection of optimized IL13BBζ-CAR Tcm resulted in robust antitumor activity and significantly improved T cell persistence compared to first-generation IL13Rα2-CAR T cells. We also found that IL13BBζ-CAR T cells administered by intracranial (i.c.) delivery outperformed intravenous delivery in MG xenograft mouse models, and were able to eradicated tumors at the primary tumor site and then traffic to tumors in the contralateral hemisphere, providing evidence for CAR T cell targeting of invasive multi-focal disease. Finally, we demonstrated that the optimized IL13BBζ-CAR Tcm, which recognize IL13Rα2 via a membrane-tethered IL13 ligand mutated at a single site (E13Y), exhibited preferential recognition of IL13Rα2 and decreased recognition of the more ubiquitously expressed IL13Rα1. In summary, these studies support the clinical applicability of this optimized IL13BBζ-CAR Tcm therapeutic product for the treatment of MG.

The rapid growth of 3G telecommunications systems has created the need of getting new test equipment as well as measurement techniques up and running in a very short time. Trying to satisfy this exigency, a measurement method for testing and troubleshooting CDMA transmitters is proposed. Thanks to the use of time-frequency representations, the method provides a unified approach for carrying out most of measurements needed to fulfill the aforementioned task automatically and in a very straightforward manner. Thus, different techniques, complex procedures, and qualified users are no longer required. After a brief outline of CDMA technology basics, the measurement principles of maintenance and troubleshooting tests on CMDA transmitters are given. The fundamental steps of the proposed method are then described with references to a clarifying example; advantages with respect to other measurement solutions are also highlighted. Finally, the method's performance is assessed by means of several experiments on emulated CDMA signals.

The sections in this article are 1 Materials Used for Sensing Devices 2 Sensor Characteristics

This paper deals with an analyser for real-time detection and analysis of transients. In particular, the analyser implements a procedure, based on the wavelet transform, suitable for analysing those disturbances which affect the power supply voltage. It utilises a good performance digital signal processor and adopts the VXI standard interface. The hardware and software solutions are described in detail. Both performance and reliability of the analyser are assessed by analysing signals characterised by different disturbances with known characteristics; the obtained results are given.

The paper deals with a signal analyzer for real time detection and analysis of transients. In particular, the analyzer implements a suitable procedure, based on the wavelet transform, for analyzing disturbances affecting the power supply voltage. It mounts a good performance digital signal processor and adopts the VXI standard interface. Hardware and software solutions are described in detail. Experimental results on signals characterized by different disturbances with known characteristics assess the reliability of the proposed analyzer.

In the bone marrow, progenitor (pro-) and precursor (pre-) B cells depend on close contact with stromal cells for growth and maturation. Stromal cell-derived factor 1 (SDF-1), also known as pre-B cell growth-stimulating factor, is produced by bone marrow stromal cells and was reported to act together with interleukin-7 as co-mitogen for pre-B cells. SDF-1 was recently shown to be a chemokine which is chemotactic for different types of leukocytes and acts via the chemokine receptor CXCR4. Using sorted B220+ bone marrow cells and several B cell lines characteristic for different stages of B lymphopoiesis, we now show that SDF-1 is a potent attractant for pro- and pre-B cells, but is inactive on B cells at later stages of development. In early B cell precursors, SDF-1 induced intracellular Ca2+ mobilization and in vitro migration with a potency and efficacy similar to that observed for chemokines acting on blood leukocytes. These responses were mediated via CXCR4 as they could be inhibited by an antireceptor antibody. SDF-1 is the first chemokine shown to act on early-stage B cell precursors. Mice lacking SDF-1 die perinatally and show a severe deficiency in B lymphopoiesis. We propose that SDF-1 released from the stromal cells exerts its critical hematopoietic function by selectively attracting and confining early B cell precursors within the bone marrow microenvironment that provides the necessary factors for growth and differentiation.

2018 Background: Human NSCs are inherently tumor-tropic, making them attractive drug delivery vehicles. This pilot-feasibility study assessed the safety of using genetically-modified NSCs for tumor selective enzyme/prodrug therapy. An immortalized, clonal NSC line was retrovirally-transduced to stably express CD, which converts the prodrug 5-FC to 5-fluorouracil (5-FU), producing chemotherapy locally at sites of tumor in the brain. Methods: Patients 18 years or older with recurrent high-grade glioma underwent intracranial administration of NSCs during tumor resection or biopsy. Four days later, 5-FC was administered orally every 6 hours for 7 days. Study treatment was given only once. A standard 3+3 dose escalation schema was used to increase doses of NSCs from 1 x 107 to 5 x 107 and 5-FC from 75 to 150 mg/kg/day. Intracerebral microdialysis was performed to measure brain levels of 5-FC and 5-FU; serial blood samples were obtained to assess systemic drug concentrations. Three patients received iron-labeled NSCs for MRI tracking. Brain autopsies were done on 2 patients. Results: Fifteen patients received study treatment. Three were inevaluable for toxicity and replaced. All patients tolerated the NSCs well. There was 1 dose-limiting toxicity (grade 3 transaminitis) possibly related to 5-FC. At the highest dose level of NSCs, the average steady-state concentration of 5-FU in the brain was 63.9±7.9 nM. The average maximum 5-FU level in brain was 104±88 nM compared to 24±36 nM in plasma, indicating local production of 5-FU in the brain by the NSCs. MR imaging of iron-labeled NSCs showed preliminary evidence of NSC migration. Autopsy data documented (by IHC, FISH, and PCR) NSCs at distant sites of tumor in the brain and no development of secondary tumors. Conclusions: This first-in-human study has demonstrated safety and proof-of-concept regarding NSC-mediated conversion of 5-FC to 5-FU and NSC tumor-tropism. NSCs have the potential to overcome obstacles of drug delivery that limit current gene therapy strategies. Results of this pilot study will serve as the foundation for future NSC studies. (Supported by NCI 1R21 CA137639-01A1, CIRM DR-01421). Clinical trial information: NCT01172964.

A model for the non-ideal behaviour of transient digitizers based on the scan conversion principle has been developed. This model allows digitizer behaviour to be investigated under several operating conditions in order to: (i) verify performance enhancement obtained through new digital signal processing techniques, (ii) develop characterization techniques peculiar to scan converters and (iii) illustrate working mechanisms and error sources with educational aims. In this paper the proposed model is described in detail and its validity and application range are illustrated through several examples. Copyright © 1996 Elsevier Science Ltd.

A cDNA clone, designated ATAC, was isolated from a collection of human T cell activation genes. Analysis of tissue distribution determined that ATAC mRNA of approximately 0.9 kb is exclusively expressed in activated CD8+ T cells. Induction of the ATAC gene requires stimulation by both phorbol 12-myristate 13-acetate and Ca2+ ionophore A23187 ("two-signal gene") and is fully abrogated by the immunosuppressive agent cyclosporin A. Upon stimulation, ATAC mRNA is detectable within 30 min, maximal expression is seen after 4 h. The polypeptide encoded by the open reading frame of ATAC mRNA is 114 amino acids long with a calculated M(r) of 12.52 kDa. The structural features predict the cleavage and secretion of a mature ATAC protein of approximately 10 kDa from the 12.52-kDa precursor. ATAC is highly similar to a very recently identified murine molecule designated lymphotactin both at the cDNA (73.8% identity) and the protein (61.4% identity) levels, and related to members of the C-C and C-X-C chemokine families. Two variants of the ATAC protein were expressed and tested for chemotaxis and Ca2+ release on a variety of target cells. The ATAC gene was located to chromosome 1q23.

This paper deals with a method for the dynamic characterization of scan conversion-based transient digitizers. Such a method is based on the application of a two-dimensional filtering process, implemented by using the Walsh transform, on the digitized data of the transient digitizer. The two-dimensional filtering process avoids the incorrect evaluation of the digitizer dynamic performance. Furthermore, a scan converter model to test the proposed method has been developed. To illustrate the validity and the application range of the method preliminary numerical results are reported. >

A knowledge-based instrument fault detection and isolation (IFDI) technique is proposed and described. It is based on the "duplication" of measurement devices by means of suitable mathematical relationships and is implemented on an expert system. The latter allows a mathematical model to be substituted by integrating qualitative models with empirical knowledge, thereby reducing overall computer effort without any corresponding decrease in diagnostic capabilities. This technique is particularly efficient when applied to detect and isolate faults in measurement systems integrated in control architectures. It is applied to an automatic measurement station for induction motor testing to illustrate its characteristics and performance. The experimental results are also reported, illustrating IFDI performance mainly in terms of promptness, sensitivity, and selectivity. >

A method for evaluating the effect of errors due to A/D converter resolution and to the finite wordlength of microprocessors in digital algorithms is described with reference to a recursive identification algorithm. The proposed method is based on a theoretical error propagation analysis which furnishes useful expressions for evaluating the role that each error source plays in the overall performance of the digital algorithm. The results obtained were verified by means of two computer simulation approaches focused respectively on the validation of error propagation and of error models. Both the theoretical study and the simulation allow one to forecast the algorithm's performance, thus allowing the measurement and computation system to be optimized on the basis of both the component under analysis and the accuracy required by the particular application.

The possibilities offered by neural networks for overcoming both system identification and fault diagnosis problems in dynamic systems are investigated. In particular, an original ″neural″ fault diagnosis procedure is illustrated; its sensitivity and response time enables it to be used to great advantage in on-line applications. Some applications are also reported which, although pertaining to a simple linear dynamic system, highlight the general applicability and advantages of a neural approach.

The use of parameter estimation techniques in practical applications requires accurate analysis of the associated measurement and computation problems. With reference to an already proposed model identification procedure, the authors deal with the experimental tests carried out in order to highlight problems and to find the most appropriate solutions. In particular, a synchronization method is described, and some suggestions concerning the optimal working conditions of all the necessary devices are reported. >

A virtual digital signal-processing instrument capable of automatically extracting and measuring disturbances superimposed on power line voltages in electrical power systems is presented here. A suitable high performance data-acquisition card is mandated to acquire and digitise the input line signal. Digital processing tasks are carried out by exploiting the properties of the wavelet transform. In particular, the continuous wavelet transform and the discrete time wavelet transform are combined in order to set up a reliable measurement method. The user interface is developed in a common iconic programming language. After some theoretical remarks about the wavelet transform and the proposed measurement method, hardware and software solutions adopted for setting up the instrument are presented. The results of the performance verification of the instrument along with those obtained from the analysis of actual superimposed power line disturbances are also given.

Jitter affecting the time base of digital-to-analog converters (DAC's) is dealt with. A new analytical model capable of describing the effects on DAC output due to deterministic jitter is proposed. Besides a detailed description of the model, very practical and usable relations are given in order to make its use very straightforward in most applications. Efficacy and reliability of the model are assessed through several experiments on an actual DAC providing different types of analog signals. Special attention is paid to digitally modulated signals peculiar to modern communication systems; their generation is a critical issue because of frequency and modulation constraints imposed by national and international standards

Modulation quality in WiMAX systems that rely on OFDM modulation is dealt with. A digital signal processing approach is, in particular, proposed, aimed at assessing the performance of transmitters in terms of standard parameters. At present, WiMAX technology deployment is at the very beginning. Also, measurement instrumentation mandated to assist WiMAX apparatuses production and installation is not completely mature, and entitled to be significantly improved in terms of functionality and performance. In particular, no dedicated instrument is already present on the market, but the available solutions are arranged complementing existing hardware, such as real-time spectrum analyzers and vector signal analyzers, with a proper analysis software. Differently from the aforementioned solutions, the proposed approach is independent of the specific hardware platform mandated to the demodulation of the incoming WiMAX signal. It can operate, in fact, with any hardware capable of achieving and delivering the baseband I and Q components of the signal under analysis. Moreover, being open-source it can be improved or upgraded according to future needs.

The rapid growth of modern telecommunications systems has created the need of getting new test equipment as well as measurement techniques up and running in a very short time. With particular regard to transmitters troubleshooting, new measurement methods and procedures are clearly claimed for, because those based on the analysis of constellation diagrams, currently supported by major manufacturers, show some intrinsic limitations. Some original and straightforward measurement procedure, based on the use of error vector (EV), which overcome the aforementioned limitations, are proposed in the paper. They are addressed to the I/Q section of transmitters, and are particularly affective both in terms of accuracy and measurement time when only one or two I/Q impairments are significant. Besides providing an analytical description, the paper gives details of the extended experimental campaign carried out on actual telecommunication signals in order to assess the performance of the proposed procedures.

Specific techniques of dynamic characterization and error correction of high-speed transient digitizers have been made available to several geographically remote users. Widely accessible geographic networking techniques and multimedia communication tools have been exploited. The feasibility of the proposed approach is shown reporting about a prototype of WWW site for scan converter-based digitizers. Experimental results of site features for remote error characterization and correction of an actual scan converter are illustrated and discussed.

The measurement method, presented in the first part of the paper, is here used in several application fields. A measurement procedure, aiming at a proper utilisation of the method according to the characteristics of the selected application field, is first described. It consists of three fundamental stages: (i) choice of the values of the measurement parameters, (ii) validation and (iii) final tuning of the procedure. The results obtained from the application of the method to thickness measurements by means of ultrasonics, power quality analysis as well as HV tests are presented. In particular, the capability of the method both in extracting measurement information from transients and removing undesirable transients superimposed on significant waveforms is highlighted.

A DSP-based FFT analyzer, capable of adapting its behavior on the basis of the specific application requirements was set up. A suitably designed user-interface allows the specific application to be chosen and its main parameters to be defined. Then an automatic optimization procedure organizes both the hardware and the software with the aim of satisfying the user requirements. The implementation on a multi-DSP architecture allows a real-time behavior to be assured. The experimental tests carried out highlight the instrument capability to optimally operate in a large number of typical applications.