Phase Synthesis Using Coupled Phase-Locked Loops

Phase Synthesis is a fundamental operation in Smart Antennas and other Phased Array systems based on beamforming. There are increasing commercial applications for Integrated Phased Arrays due to their low cost, size and power and also because the RF and digital signal processing can be performed on the same chip. These low cost beamforming applications have augmented interest in Coupled Phase Locked Loop (CPLL) systems for Phase Synthesis. Previous work on the implementation of Phase Synthesis systems using Coupled PLLs for low cost beamforming had the constraint of a limited phase range of ±90°. The idea behind the thesis is that this phase synthesis range can be increased to ±180° through the use of PLLs employing Phase Frequency Detectors(PFDs), which is a significant improvement over conventional coupled-PLL systems. This work presents the detailed design and measurement results for a phase synthesizer using Coupled PLLs for achieving phase shift in the range of ±180°. Several Coupled PLL architectures are investigated and their advantages and limitations are evaluated in terms of frequency controllability, phase difference synthesis control and phase noise of the systems. A two-PLL system implementation using off the shelf components is presented, which generates a steady-state phase difference in the range ±180° using an adjustable DC control current. This is the proof of concept for doing an IC design for a Coupled Phase Locked Loop system. Commercial applications in the Wireless Medical Telemetry Service (WMTS) band motivate the design of a CPLL system in the 608-614 MHz band. The design methodology is presented which shows the flowchart of the IC design process from the system design specifications to the transistor level design. MATLAB simulations are presented to model the system performance quickly. VerilogA modeling of the CPLL system is performed followed by the IC design of the system and each block is simulated under different process and temperature corners. The transistor level design is then evaluated for its performance in terms of phase difference synthesis and phase noise and compared with the initial MATLAB analysis and improved iteratively. The CPLL system is implemented in IBM 130nm CMOS process and consumes 40mW of power from a 1.2V supply with a phase noise performance of -88 dBc/Hz for 177° phase generation

Aeromagnetic signatures of Precambrian shield and suture zones of Peninsular India

AbstractIn many Precambrian provinces the understanding of the tectonic history is constrained by limited exposure and aeromagnetic data provide information below the surface cover of sediments, water, etc. and help build a tectonic model of the region. The advantage of using the aeromagnetic data is that the data set has uniform coverage and is independent of the accessibility of the region. In the present study, available reconnaissance scale aeromagnetic data over Peninsular India are analyzed to understand the magnetic signatures of the Precambrian shield and suture zones thereby throwing light on the tectonics of the region. Utilizing a combination of differential reduction to pole map, analytic signal, vertical and tilt derivative and upward continuation maps we are able to identify magnetic source distribution, tectonic elements, terrane boundaries, suture zones and metamorphic history of the region. The magnetic sources in the region are mainly related to charnockites, iron ore and alkaline intrusives. Our analysis suggests that the Chitradurga boundary shear and Sileru shear are terrane boundaries while we interpret the signatures of Palghat Cauvery and Achankovil shears to represent suture zones. Processes like metamorphism leave their signatures on the magnetic data: prograde granulites (charnockites) and retrograde eclogites are known to have high susceptibility. We find that charnockites intruded by alkali plutons have higher magnetization compared to the retrogressed charnockites. We interpret that the Dharwar craton to the north of isograd representing greenschist to amphibolite facies transition, has been subjected to metamorphism under low geothermal conditions. Some recent studies suggest a plate tectonic model of subduction–collision–accretion tectonics around the Palghat Cauvery shear zone (PCSZ). Our analysis is able to identify several west to east trending high amplitude magnetic anomalies with deep sources in the region from Palghat Cauvery shear to Achankovil shear. The magnetic high associated with PCSZ may represent the extruded high pressure–ultra high temperature metamorphic belt (granulites at shallow levels and retrogressed eclogites at deeper levels) formed as a result of subduction process. The EW highs within the Madurai block can be related to the metamorphosed clastic sediments, BIF and mafic/ultramafic bodies resulting from the process of accretion

Preliminary Phytochemical Screening of wild edible fruits from Boda and Kolli hills

Medicinal plant plays a vital role for ailment of various chronic diseases due to the presence of phytochemical constituent. The preliminary phytochemical compounds was studied by using the ethanol, ethyl acetate, diethyl ether, chloroform and aqueous extracts of 15 wild edible fruits collected from Boda and Kolli Hills. The phytochemical compounds such as Phenol, tannins, saponin, alkaloid, flavonoids, steroids, phlobotannins, terpenoids, anthroquinones and cardiac glycosides were screened in 15 edible fruits by using standard methods. The diethyl ether extract, ethyl acetate and ethanol extract of the selected fruits shows the presence of phytochemicals compound. The highest occurrence shows the high therapeutic value possessing majority of phytochemical constituent of active compounds. In Further studies, the compound from these fruits were isolated and used for medicinal purpose

Asian Elephant and Bannerghatta National Park in Eastern Ghats, Southern India

The park lies between 120 34’and 120 50’N latitudes and between 770 31’and 770 38’E longitudes (Rajeev 2002). The park area has been divided into three wildlife ranges, Viz. Bannerghatta, Harohalli and Anekal Wildlife Range for the convenience of administration. It is highly irregular in shape and measures a maximum of 26 km in length from North to South and varies between 0.3 and 5 km in widt

Asian Elephant and Bannerghatta National Park in Eastern Ghats, Southern India

The park lies between 120 34’and 120 50’N latitudes and between 770 31’and 770 38’E longitudes (Rajeev 2002). The park area has been divided into three wildlife ranges, Viz. Bannerghatta, Harohalli and Anekal Wildlife Range for the convenience of administration. It is highly irregular in shape and measures a maximum of 26 km in length from North to South and varies between 0.3 and 5 km in widt

Phase diagram and upper critical field of homogenously disordered epitaxial 3-dimensional NbN films

We report the evolution of superconducting properties with disorder, in 3-dimensional homogeneously disordered epitaxial NbN thin films. The effective disorder in NbN is controlled from moderately clean limit down to Anderson metal-insulator transition by changing the deposition conditions. We propose a phase diagram for NbN in temperature-disorder plane. With increasing disorder we observe that as kFl-->1 the superconducting transition temperature (Tc) and minimum conductivity (sigma_0) go to zero. The phase diagram shows that in homogeneously disordered 3-D NbN films, the metal-insulator transition and the superconductor-insulator transition occur at a single quantum critical point at kFl~1.Comment: To appear in Journal of Superconductivity and Novel Magnetism (ICSM2010 proceedings

Readmissions, death and its associated predictors in heart failure with preserved versus reduced ejection fraction

BACKGROUND: Data on rehospitalizations for heart failure (HF) in Asia are scarce. We sought to determine the burden and predictors of HF (first and recurrent) rehospitalizations and all‐cause mortality in patients with HF and preserved versus reduced ejection fraction (preserved EF, ≥50%; reduced EF, <40%), in the multinational ASIAN‐HF (Asian Sudden Cardiac Death in Heart Failure) registry. METHODS AND RESULTS: Patients with symptomatic (stage C) chronic HF were followed up for death and recurrent HF hospitalizations for 1 year. Predictors of HF hospitalizations or all‐cause mortality were examined with Cox regression for time to first event and other methods for recurrent events analyses. Among 1666 patients with HF with preserved EF (mean age, 68±12 years; 50% women), and 4479 with HF with reduced EF (mean age, 61±13 years; 22% women), there were 642 and 2302 readmissions, with 28% and 45% attributed to HF, respectively. The 1‐year composite event rate for first HF hospitalization or all‐cause death was 11% and 21%, and for total HF hospitalization and all‐cause death was 17.7 and 38.7 per 100 patient‐years in HF with preserved EF and HF with reduced EF, respectively. In HF with preserved EF, consistent independent predictors of these clinical end points included enrollment as an inpatient, Southeast Asian location, and comorbid chronic kidney disease or atrial fibrillation. The same variables were predictive of outcomes in HF with reduced EF except atrial fibrillation, and also included Northeast Asian location, older age, elevated heart rate, decreased systolic blood pressure, diabetes, smoking, and non‐usage of beta blockers. CONCLUSIONS: One‐year HF rehospitalization and mortality rates were high among Asian patients with HF. Predictors of outcomes identified in this study could aid in risk stratification and timely interventions. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01633398

Prevalence and Prognostic Significance of Frailty in Asian Patients With Heart Failure:Insights From ASIAN-HF

Background: Frailty is common in patients with heart failure (HF) and can adversely impact outcomes. Objectives: This study examined the prevalence of frailty among Asian patients with HF, its association with 1-year outcomes, and if race-ethnicity, HF subtypes, and sex modify this relationship. Methods: In the multinational ASIAN-HF (Asian Sudden Cardiac Death in Heart Failure) registry, a baseline frailty index (FI) was constructed using a cumulative deficits approach with 48 baseline variables, and patients were followed for the 1-year primary outcome of all-cause death or HF hospitalization. Results: Among 3,881 participants (age 61 ± 13 years, 27% female), the mean FI was 0.28 ± 0.11, and 69% were frail (FI &gt;0.21). Higher FI was associated with older age, Malay ethnicity, and Southeast Asian residency. While comorbidities were more frequent in frail patients (by definition), body mass index was not different across frailty classes. Compared with FI class 1 (&lt;0.21, nonfrail), FI class 2 (0.21-0.31) and FI class 3 (&gt;0.31) had increased risk of the 1-year composite outcome (hazard ratios of 1.84 [95% confidence interval (CI): 1.42-2.38] and 4.51 [95% CI: 3.59-5.67], respectively), even after multivariable adjustment (adjusted hazard ratios of 1.49 [95% CI: 1.13-1.97] and 2.69 [95% CI: 2.06-3.50], respectively). Race-ethnicity modified the association of frailty with the composite outcome (Pinteraction = 0.0097), wherein the impact of frailty was strongest among Chinese patients. The association between frailty and outcomes did not differ between men and women (Pinteraction = 0.186) or for HF with reduced ejection fraction versus HF with preserved ejection fraction (Pinteraction = 0.094). Conclusions: Most Asian patients with HF are frail despite relatively young age. Our results reveal specific ethnic (Malay) and regional (Southeast Asia) predisposition to frailty and highlight its prognostic importance, especially in Chinese individuals.</p

Prevalence and Prognostic Significance of Frailty in Asian Patients With Heart Failure:Insights From ASIAN-HF

Background: Frailty is common in patients with heart failure (HF) and can adversely impact outcomes. Objectives: This study examined the prevalence of frailty among Asian patients with HF, its association with 1-year outcomes, and if race-ethnicity, HF subtypes, and sex modify this relationship. Methods: In the multinational ASIAN-HF (Asian Sudden Cardiac Death in Heart Failure) registry, a baseline frailty index (FI) was constructed using a cumulative deficits approach with 48 baseline variables, and patients were followed for the 1-year primary outcome of all-cause death or HF hospitalization. Results: Among 3,881 participants (age 61 ± 13 years, 27% female), the mean FI was 0.28 ± 0.11, and 69% were frail (FI &gt;0.21). Higher FI was associated with older age, Malay ethnicity, and Southeast Asian residency. While comorbidities were more frequent in frail patients (by definition), body mass index was not different across frailty classes. Compared with FI class 1 (&lt;0.21, nonfrail), FI class 2 (0.21-0.31) and FI class 3 (&gt;0.31) had increased risk of the 1-year composite outcome (hazard ratios of 1.84 [95% confidence interval (CI): 1.42-2.38] and 4.51 [95% CI: 3.59-5.67], respectively), even after multivariable adjustment (adjusted hazard ratios of 1.49 [95% CI: 1.13-1.97] and 2.69 [95% CI: 2.06-3.50], respectively). Race-ethnicity modified the association of frailty with the composite outcome (Pinteraction = 0.0097), wherein the impact of frailty was strongest among Chinese patients. The association between frailty and outcomes did not differ between men and women (Pinteraction = 0.186) or for HF with reduced ejection fraction versus HF with preserved ejection fraction (Pinteraction = 0.094). Conclusions: Most Asian patients with HF are frail despite relatively young age. Our results reveal specific ethnic (Malay) and regional (Southeast Asia) predisposition to frailty and highlight its prognostic importance, especially in Chinese individuals.</p