Journal articles on the topic 'Virtual multimeter'

The sensor is a kind of device about electrochemical science, its applications include clinical and environmental analyses, physiology, and process control; therefore, how to accurately detect the signal of the sensor is one of the most important things for analyzing the characteristics of sensor. For potentiometric device, this study relates to a multielectrode measurement system based on the programable software, LabVIEW, forming a virtual instrument (VI). This system is built as a voltage versus time (V–T) framework and a dynamic detection system. We selected two devices, a digital multimeter (HP 34401A) and a homemade VI, synchronously to measure the sources of a direct current (DC) signal and an electrode cell (EC), respectively. The maximum errors between the two devices are 0.639 mV in DC supply and 0.345 mV in EC supply, which specifies that the efficiency of design measurement system is good for detection.

According to the function, the technical indexes and the cost control etc, we select the embedded control computer and virtual instrument module based on the PXI, and developed the integrated multipurpose instrument calibrating equipment, it realized the field measurement and calibration of the electrical instrument away from the laboratory. The system is designed based on PXI and LabVIEW, it uses virtual instrument technology, automatic control technology and database technology, by combining these functional modules of NI, we realized the calibration of electrical instruments such as digital multimeter, signal generator, oscilloscope and cymometer etc. The system is used integrated design, and it is very flexible, it can be popularized and applied as working standard to troops, factories or schools etc.

The aim of this paper is to present the simulation and experiment of the welding butt-joint aluminum alloys to low carbon steel using Visual-weld software and the metal inert gas (MIG) welding process. The workpiece is set up in a virtual environment with an area of 150 x 70 x 5 mm, a welding speed at 3.5 mm/s, and a heating source of 2.5 kW. The finite element method (FEM) is used as a powerful tool in simulating, calculating and predicting the welding stress and distortion at the early stage of the design process and development of welding products. The metallurgical process, deformation, hardness, etc. are investigated using the FEM in Sysweld software. The microstructure of the intermetallic layer is observed using scanning electron microscopy. The hardness of the intermetallic layer is examined using Vickers hardness testing. Tensile strength and bending strength are examined by tensile and compress multimeter equipment. To improve the quality of the aluminum/steel welds, the IMCs layer should be as small as possible. The experimental results are better if the welding current of range of 95 – 100 A and the welding speed is from 3.5 to 4 mm/s.

Abstract Abstract 1215 The diagnosis of von Willebrand disease (VWD) and discrimination between its subtypes includes analysis of VWF:Ag, VWF:RCo, and VWF multimer structure. VWF multimer analysis is qualitative, and therefore a subjective assessment open to interpretation. It is often difficult to assess subtle differences in multimer structure. To address these shortcomings we have developed a quantitative method for analysis of VWF multimers. We have analyzed multimer structure for VWD patients and healthy controls recruited through the Zimmerman Program for the Molecular and Clinical Biology of von Willebrand Disease (ZPMCB-VWD). The patient population includes type 1 and type 2 VWD with well-defined genotypes and phenotypes. Multimer analysis was performed using a 0.65% LiDS-agarose gel electrophoresis system and western blotting with chemilumiscent detection using the Fujifilm LAS-3000 luminescent image analyzer. Densitometry was performed and area-under-the-curve calculated using MultiGauge analysis software. We calculated the percentage of low molecular weight (LMW) multimers defined as bands 1 – 5, mid-molecular weight (MMW) multimers (bands 6 – 10) and high molecular weight (HMW) multimers (bands >10). For healthy controls, the distribution of multimer density (mean ± standard deviation) was 25.3 ± 2.7% HMW, 56.1 ± 4.9% MMW, and 18.6 ± 3.4% LMW. Type 1 VWD (including type 1C) patients had a similar distribution of multimers (22.5 ± 7.6% HMW, 48.5 ± 6.7% MMW, 29.0 ± 7.2 % LMW), although there was a slight shift in distribution to increased LMW. For some type 1C patients with mutations including C1130Y and W1144G, we observed a small loss of HMW multimers (14.2 ± 0.8% HMW, 51.1 ± 1.4% MMW, 34.7 ± 2.3% LMW), as has been previously reported in patients with a C1130F variation. In contrast, some patients with the type 1C “Vicenza” mutation, R1205H, demonstrated increased HMW multimers (32.6 ± 1.0% HMW, 42.2 ± 4.0% MMW, 25.2 ± 3.0% LMW) as previously reported. Although the multimers in the type 1 patients are essentially normal, quantitative analysis reveals subtle abnormalities in structure. In type 2B VWD patients with mutations including V1316M, R1306W, and R1341W, a loss of HMW and MMW multimers was observed (7.1 ± 3.2% HMW, 40.4 ± 8.3% MMW, and 52.5 ± 11.4% LMW). A greater loss of HMW and MMW multimers was observed in patients with type 2A VWD with mutations including Y1349C, R1597W, G1609R, I1628T, G1631D, and G1670S (3.5 ± 6.2% HMW, 19.7 ± 20.4% MMW, and 76.9 ± 26.3% LMW). The type 2A subjects consisted of two groups: those with a virtually complete loss of HMW and MMW (0.0 ± 0% HMW, 4.0 ± 1.0% MMW, and 96.0 ± 1.0% LMW), and those with loss of HMW and decreased MMW (8.7 ± 7.5% HMW, 41.0 ± 14.7% MMW, and 50.3 ± 20.9% LMW). The latter group had a similar multimer distribution to that of type 2B VWD subjects. While most type 2A patients with mutations associated with increased susceptibility to ADAMTS13 proteolysis had severe multimer abnormalities (>95% LMW), some had only moderate abnormalities. Our study demonstrates that quantitative analysis of VWF multimer patterns more clearly distinguishes patients with various subtypes of VWD than subjective analysis. Although one of the two groups of type 2A patients is similar to the type 2B group, the other group is clearly different and is associated with specific genotypes, perhaps eliminating the need for DNA sequence analysis to make a definitive diagnosis for this group. This technique provides an objective measure of VWF structure to better characterize subtle changes observed in the subtypes of VWD and may help to determine the nature of any additional clinical laboratory testing to reach a clear-cut diagnosis. Disclosures: No relevant conflicts of interest to declare.

Abstract TGF-β- (transforming growth factor-β-) mediated signal transduction affects growth and patterning in a variety of organisms. Here we report a genetic characterization of the Drosophila punt gene that encodes a type II serine/threonine kinase TGF-β/Dpp (Decapentaplegic) receptor. Although the punt gene was originally identified based on its requirement for embryonic dorsal closure, we have documented multiple periods of punt activity throughout the Drosophila life cycle. We demonstrate that potentially related embryonic punt phenotypes, defects in dorsoventral patterning and dorsal closure, correspond to distinct maternal and zygotic requirements for punt. In addition, we document postembryonic requirements for punt activity. The tight correspondence between both embryonic and postembryonic loss-of-function punt and dpp phenotypes implicates a role for Punt in mediating virtually all Dpp signaling events in Drosophila. Finally, our comparison of punt homoallelic and heteroallelic phenotypes provides direct evidence for interallelic complementation. Taken together, these results suggest that the Punt protein functions as a dimer or higher order multimer throughout the Drosophila life cycle.

Abstract Abstract 2273 Background: Continuous flow left ventricular assist device (CF-LVAD) recipients have high tendency of post-surgical gastrointestinal (GI) bleeding. We previously described the loss of high molecular weight VWF multimers (HMWM), due to either an accelerated clearance or enhanced cleavage of the HMWM, in most CF-LVAD recipients (Ann Thorac Surg. 90:1263–9). However, besides the tedious plasma VWF multimer analysis, neither VWF ristocetin cofactor nor collagen binding activity assay provides sufficient sensitivity for detecting such an acquired VWF abnormality (AVWA). In this study, we examined a new automated latex particle-enhanced immunoturbidimetric VWF activity assay (VWF:Lx) for its ability of detecting CF-LVAD-AVWA. We also analyzed the VWF pro-peptide (VWF:pp) to explored the potential mechanism of CF-LVAD-AVWA. Design: As part of an on-going prospective multicenter study, pre- and post-CF-LVAD implantation (7, 30 days and 5–7 months) blood samples were collected from 15 LVAD recipients (median age 52 years; 10 male and 5 female; 2008∼2009). Plasma VWF antigen (VWF:Ag), VWF:Lx activity, VWF:pp/Ag ratios were measured; and plasma VWF multimer analyses were performed on all available plasma samples. Standard statistical analyses were employed. Result: Loss of VWF HMWM was observed in 3 patients prior to CF-LVAD implantation and virtually all patients after surgery. VWF:Ag, VWF:Lx or VWF:pp/Ag ratios of the pre- and post-implantation samples were not significantly different (P> 0.1). However, VWF:Lx/Ag ratios of the post-implantation samples were significantly decreased (P<0.05). At a cut off of 0.8, the VWF:Lx/Ag ratio has a 90% sensitivity and specificity for detecting AVWA. Conclusions: VWF:Lx/Ag ratio has excellent sensitivity and specificity in detecting CF-LVAD-AVWA, and its impact on predicting post-surgical bleeding tendency in CF-LVAD recipients is being investigated. The distinct CF-LVAD-AVWA is most likely caused by enhanced cleavage, rather than clearance, of the HMWM. Disclosures: No relevant conflicts of interest to declare.

VP16 (termed VP16-H here) of herpes simplex virus (HSV) belongs to a family of related regulatory proteins which includes VP16-B of bovine herpesvirus (BHV). We show that VP16-B, while also being a powerful transactivator of transcription dependent on Oct-1 binding sites in its target promoters, has virtually no activity on a defined VP16-H-responsive, octamer-containing target promoter. While Oct-1 binds equally well to the VP16-B-responsive and -nonresponsive sites, VP16-B interacts with Oct-1 only when Oct-1 is bound to the BHV octamer site and not when it is bound to the HSV site. We show from the analysis of chimeric proteins that the ability of VP16-B to discriminate between the Oct-1 forms depends on features of its N-terminal region. We also show from an analysis of chimeric DNA motifs that sequences that lie 3' to the POU domain-contacting region of the HSV octamer site play a role in making it unresponsive to VP16-B. Finally, we show by high-resolution hydroxyl radical footprint analysis that the conformation of Oct-l is different on the two sites. These results augment our previous report on an allosteric effect of DNA signals on the conformation of bound proteins and indicate that different conformations of the same DNA binding protein can be recognized selectively by related members of interacting regulatory proteins. The possible implications of our observations for selective gene regulation by Oct-1, a ubiquitous transcription factor, and other multimember transcription families are discussed.

Abstract von Willebrand factor (vWF) is a multimeric adhesive glycoprotein essential for normal hemostasis. We have discovered that cultured human umbilical vein endothelial cells incorporate inorganic sulfate into vWF. Following immunoisolation and analysis by polyacrylamide or agarose gel electrophoresis, metabolically labeled vWF was found to have incorporated [35S]-sulfate into all secreted multimer species. The time course of incorporation shows that sulfation occurs late in the biosynthesis of vWF, near the point at which multimerization occurs. Quantitative analysis suggests the presence, on average, of one molecule of sulfate per mature vWF subunit. Virtually all the detectable sulfate is released from the mature vWF subunit by treatment with endoglycosidases that remove asparagine-linked carbohydrates. Sulfated carbohydrate was localized first to the N-terminal half of the mature subunit (amino acids 1 through 1,365) by partial proteolytic digestion with protease V8; and subsequently to a smaller fragment within this region (amino acids 273 through 511) by sequential digestions with protease V8 and trypsin. Thus, the carbohydrate at asparagine 384 and/or 468 appears to be the site of sulfate modification. Sodium chlorate, an inhibitor of adenosine triphosphate- sulfurylase, blocks sulfation of vWF without affecting either the ability of vWF to assemble into high molecular weight multimers or the ability of vWF multimers to enter Weible-Palade bodies. The stability of vWF multimers in the presence of an endothelial cell monolayer also was unaffected by the sulfation state. Additionally, we have found that the cleaved propeptide of vWF is sulfated on asparagine-linked carbohydrate.

von Willebrand factor (vWF) is a multimeric adhesive glycoprotein essential for normal hemostasis. We have discovered that cultured human umbilical vein endothelial cells incorporate inorganic sulfate into vWF. Following immunoisolation and analysis by polyacrylamide or agarose gel electrophoresis, metabolically labeled vWF was found to have incorporated [35S]-sulfate into all secreted multimer species. The time course of incorporation shows that sulfation occurs late in the biosynthesis of vWF, near the point at which multimerization occurs. Quantitative analysis suggests the presence, on average, of one molecule of sulfate per mature vWF subunit. Virtually all the detectable sulfate is released from the mature vWF subunit by treatment with endoglycosidases that remove asparagine-linked carbohydrates. Sulfated carbohydrate was localized first to the N-terminal half of the mature subunit (amino acids 1 through 1,365) by partial proteolytic digestion with protease V8; and subsequently to a smaller fragment within this region (amino acids 273 through 511) by sequential digestions with protease V8 and trypsin. Thus, the carbohydrate at asparagine 384 and/or 468 appears to be the site of sulfate modification. Sodium chlorate, an inhibitor of adenosine triphosphate- sulfurylase, blocks sulfation of vWF without affecting either the ability of vWF to assemble into high molecular weight multimers or the ability of vWF multimers to enter Weible-Palade bodies. The stability of vWF multimers in the presence of an endothelial cell monolayer also was unaffected by the sulfation state. Additionally, we have found that the cleaved propeptide of vWF is sulfated on asparagine-linked carbohydrate.

Abstract Exchange transfusion (ET) is a standard procedure in newborn infants with severe hyperbilirubinemia. Although infant’s whole blood volume is exchanged with adult blood containing different amounts of coagulation factors and anticoagulants, the effects of ET on newborn blood coagulation system remain virtually unstudied. We now prospectively evaluated the effect of ET on thrombin formation and on coagulation profile in newborns. ET was performed by composite blood (200mL/kg). After parental consent the blood samples were collected from the infused blood and from the arterial line of newborns (n=16) at the beginning (pre-ET), at the end (post-ET), and two hours after completing ET. The samples were assayed for platelet count, thrombin-antithrombin complexes (TAT), prothrombin fragment F1+2, FV, FVII, FVIII, antithrombin, protein C, protein S, von Willebrandt factor (vWf) multimers, and for tissue factor-initiated thrombin formation (endogenous thrombin potential - ETP, thrombin peak) with or without added activated protein C (APC). Venous blood from 9 healthy adults and cord blood from 8 deliveries of healthy women were used as controls. TAT increased significantly during ET and returned to pre-ET levels two hours after the ET (Figure). F1+2 changed similarly with TAT. Platelet count was significantly reduced during ET (Pre-ET 272±23 109/L vs. Post-ET 45±4 109/L; mean±SEM; p=0.0005). The measured coagulation factors and anticoagulants increased significantly (p&lt;0.05), except FV. At the end of ET the newborn plasma levels of FV, FVII, antithrombin, and protein S were similar with the respective levels in the infused blood, whereas protein C levels remained lower (p&lt;0.001) and FVIII higher (p&lt;0.001) than in the infused blood. The functional high-molecular weight forms of vWf multimers in newborn plasma were reduced during ET, thus changing the multimer distribution to an adult-like pattern. The pre-ET thrombin peak level and ETP were similar with cord control group but only ~60% of adult levels. ETP increased in the newborn plasma during ET reaching adult levels. APC decreased ETP in newborn plasma similarly at the beginning (31±5%) and at the end (35±4%) of ET. This thrombin reduction by APC was similar with cord control group but significantly less (p&lt;0.0001) than the decrease achieved by APC in adults (79±4%); thus the resistance to APC, characteristic to newborn plasma, remained the same throughout ET. In conclusion, ET causes profound temporary thrombin escalation despite the procedure-associated thrombocytopenia. Multiple procoagulant changes in post-ET plasma could be demonstrated partially explaining the enhanced thrombin formation. ET-induced coagulopathy may be clinically significant in sick newborns already prone to bleeding and thrombotic complications. Figure. The evolution of TAT around exchange transfusion in newborn infants (median, 25th and 75th percentile, minimun and maximum; n = 16; • = outlier). Wilcoxon test was used for comparisons. Figure. The evolution of TAT around exchange transfusion in newborn infants (median, 25th and 75th percentile, minimun and maximum; n = 16; • = outlier). Wilcoxon test was used for comparisons.

Abstract Background: Von Willebrand disease (vWD) is the most common inherited bleeding disorder worldwide. Genetic mutations in the von Willebrand gene may result in either quantitative (Types 1 and 3 vWD) or qualitative defects (Type 2 vWD) of von Willebrand Factor (vWF). Type 3 is the rarest and most severe form of vWD, resulting in a virtual absence of vWF. Type 3 vWD follows autosomal recessive inheritance and is most often reported in patients who are homozygous for the same gene mutation. We report a patient with type 3 vWD who inherited two different mutations, one from each parent, resulting in compound heterozygosity. Case: Our patient, now a 2 year old female, initially presented with prolonged bleeding lasting approximately 5 hours at the injection site of her 2 month immunizations. Labs on initial presentation showed a normal WBC count, hemoglobin, hematocrit, and platelet count, with normal levels of Factor IX, XI, and XII activity. PTT was prolonged at 59 (reference range 23.3-35.7) with a normal INR. Von Willebrand panel showed markedly decreased Factor VIII (2%), vWF antigen (6%), and vWF activity (8%). VWF multimers were absent, consistent with a diagnosis of type 3 vWD. VWF gene sequence analysis showed two pathologic variants, one on each allele: c2345delC in exon 18 and a deletion within exon 6. Her parents, both 27 years old and with no history of abnormal bleeding, are non-consanguineous. Analysis of parents for vWD revealed that mother is heterozygous for the c2345delC variant and the patient's father is heterozygous for the deletion within exon 6 of the VWF gene. The patient's older sibling who is now 4 years old developed unusual petechiae and bruising after an altercation at school, his testing was positive for only the maternal mutation, resulting in a diagnosis of Type 1 vWD, and a younger brother was negative for both mutations. Our patient has subsequently suffered recurrent episodes of bruising, gingival bleeding, and poor tissue healing and currently requires replacement therapy (prophylaxis) with Humate-P three times each week and additionally as needed. Discussion: Type 3 vWD is quite rare, with a prevalence ranging from 0.1-5.3 per million. Our case is especially interesting due to the unique inheritance pattern resulting in our patient's type 3 vWD phenotype. Type 3 vWD cases are often described in patients homozygous for a mutation in the VWF gene, frequently as a result of consanguinity. Our patient inherited a unique variant from each parent, resulting in heterozygous expression of two defective VWF alleles (compound heterozygosity). Our patient's maternally inherited defect c2435delC in exon 18 is the variant found in the original vWD family described by Dr. Erik von Willebrand in 1926. Less is understood about the paternally inherited defect of a deletion in exon 6 of VWF. In our patient's family, because each parent is heterozygous for a mutation in the VWF gene, future children have a 75% chance of inheriting at least one mutation, and a 25% chance of inheriting both mutations, leading to Type 3 vWD. Type 3 vWD patients have impaired endogenous synthesis of functional vWF, thus therapies such as desmopressin, used in other types of vWD to stimulate secretion of endogenous vWF, are ineffective. Instead, first-line treatment in Type 3 is replacement therapy with Humate-P as needed during bleeding episodes and/or as prophylaxis. Humate P is VWF/FVIII concentrate obtained from pooled human plasma from many carefully screened plasma donors and contains the clotting proteins VWF and FVIII. Humate-P has a VWF:FVIII ratio of approximately 2.4:1. Complications of therapy include the rare development of anti-vWF alloantibodies, which most often occurs in patients with partial or complete VWF gene deletions. Our patient has received aminocaproic acid for minimal bleeding episodes and due to her severe intensity of disease and age of increased risk of injuries had received plasma derived vWF/FVIII concentrates for multiple episodes of moderate bleeding. She has not developed antibodies yet, but is at high risk. The rWVF (recombinant von Willebrand factor) offers new perspective in treatment of vWD more so with type 3 disease. It is a homogenous protein synthesized by a genetically engineered Chinese hamster ovary (CHO) cell line, retains its intact multimer pattern because it is never exposed to proteases(ADAMTS13) which can degrade it. The rVWF is currently in phase 3 clinical trials Disclosures No relevant conflicts of interest to declare.

Abstract Chimeric-antigen receptor (CAR)-T cell immunotherapy is a promising type of cancer therapy and substantial progress has been made in developing adoptive T cell approaches for B cell malignancies. B cell maturation antigen (BCMA) is an attractive target for patients with multiple myeloma (MM) due to its high level of expression on tumor cells and restricted expression on normal tissues. Traditionally, the antigen-binding domain of a CAR is a single chain variable fragment (scFv) comprised of heavy chain (HC) and light chain (LC) variable fragments joined by a flexible linker that has been derived from a non-human monoclonal Ab (mAb). However, there are a number of disadvantages to scFv-based CARs including the limited availability of scFv, their potential to elicit antibody responses, and their association with tonic signaling due, in part, to inherent instability and flexibility of the structure and the potential for both HC/LC domain swapping and multimer formation through framework region interactions. Thus, replacement with alternative binding technologies may improve CAR-T efficacy in the clinic. Centyrins are alternative scaffold molecules that bind protein targets with high affinity and specificity, similar to scFv molecules. However, unlike scFv, Centyrins are smaller, derived from human consensus tenascin FN3 domains and are predicted to have decreased immunogenicity. Additionally, a monomeric Centryin in CAR format (i.e. CARTyrin molecule) is less likely to engage in domain swapping or interact with other Centyrins at the cell surface, thereby limiting the potential for the tonic signaling that drives the functional exhaustion of CAR T cells. Centyrins can be isolated against virtually any antigen through ex vivo panning of an extensive Centyrin library, yielding many distinct binders with a range of affinities and target epitopes. Panning with soluble BCMA protein yielded a large pool of BCMA-specific Centyrins, from which 11 distinct monomeric binders and 1 non-monomeric binder were selected for further study in CAR format. In addition, we tested numerous signal peptides, linkers, transmembrane domains and signaling domains to determine optimal configuration. We then created all CARTyrins by fusing each Centyrin with a CD8a leader peptide, spacer and transmembrane domain, as well as an intracellular signaling domain derived from both 4-1BB and CD3ζ. High quality mRNA of each CARTyrin construct was produced in order to rapidly screen CARTyrin cell surface expression and functionality in human pan T cells against BCMA+ targets. We also constructed scFv-based CARs against CD19 and BCMA for comparison. Previously CD3/CD28-stimulated T cells were electroporated (EP) with mRNA encoding each of the 12 anti-BCMA CARTyrins and, the following day, analyzed for surface expression of CARTyrin and their ability to degranulate against BCMA+ tumor cells. All 12 CARTyrins were detected on the cell surface and the 11 monomeric CARTyrins imparted BCMA-specific killing capacity to T cells. Notably, in these assays, CARTyrins were functionally comparable to scFv-based CARs against BCMA or to CD19-specific scFv-based CARs in a parallel assay with CD19+ tumor cells. The 11 functional anti-BCMA CARTyrins were further characterized for functional avidity by determining their activity against a panel of target cells with titrated levels of surface BCMA expression. To create this panel, various amounts of high quality BCMA mRNA were electroporated into BCMA- K562 tumor cells. After 4 hours of co-culture with the panel of BCMA expressing cells, CARTyrin+ T cell activity was measured as a function of CD107a expression. We observed a range of activities by each CARTyrin and show that this assay can be utilized to determine the minimal effective dose of BCMA needed to induce killing by CARTyrin+ cells. Furthermore, we establish that certain BCMA-specific CARTyrins are responsive to target cells with extremely low levels of surface BCMA expression. These results confirm that Centyrins are viable replacements for scFv in the construction of functional CARs and establish their potential utility in generating novel BCMA-specific CAR molecules, as well as other novel targetable tumor antigens. Disclosures Barnett: Poseida Therapeutics: Employment. Wang:Poseida Therapeutics: Employment. Hermanson:Poseida Therapeutics: Employment. Tan:Poseida Therapeutics: Employment. Osertag:Poseida Therapeutics: Employment, Equity Ownership. Shedlock:Poseida Therapeutics: Employment.

In this paper, an accurate I-V virtual instrument (VI) that has been developed to characterize electronic devices for research and teaching purposes is demonstrated. The virtual instrument can be used to highlight principles of measurement, instrumentation, fundamental principles of electronics, VI programming, device testing and characterization in wafer or discrete device level. It consists of a Keithley electrometer, model 6514, a programmable power supply BK Precision, model 1770, a Keithley source meter, model 2400-LV, an Agilent digital multimeter, model 34401, a PC computer and LabVIEW software. The instruments are interconnected using an IEEE 488 protocol. The characteristic VI devices graphs are generated from measured data previous computational processing. The instrument is used in basic courses of physical electronics as well as in advance curses of VLSI design and in research work for characterization of semiconductor materials and devices. This paper describes the VI instrument design, implementation and characterization experiments.

The aim of this paper is to develop an Automated Test System (ATS) for the Test and Evaluation of C-Band Transmitter packages for GEOSAT Space crafts using Virtual Instrumentation. Efficiency, coverage, quality and accuracy for the test and evaluation of Device Under Test (DUT) can be increased by Automated Testing. Minimizing the errors anticipated with manual intervention. Automated Test System using Virtual instrumentation (VI) combines rapid development software and modular, flexible hardware to create user-defined test systems. Here Modular PXI (Peripheral component interface Extensions for Instrumentation) instruments from National Instruments are used with NI-LabVIEW software for realizing the ATS. For characterizing the C-Band Transmitter, Spectrum analyzer & Digital Multimeter (DMM) is configured in PXI form-factor and the Power supply is controlled through GPIB (General Purpose Interface Bus) bus. The complete software is developed using NI LabVIEW which takes care of configuring the test condition and analyzing the DUT performance. The user friendly GUI well takes care of user interaction to the ATS.