http://nopr.niscair.res.in/handle/123456789/4065 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/4084 Title: Performance of non-linear amplifier based phase locked loop systems in presence of channel perturbations <br/> <br/>Authors: De, B; Sarkar, B C <br/> <br/>Abstract: The tracking performance of non-linear amplifier based conventional second order phase locked loop (PLL) and charge pump phase locked loop have been examined numerically by solving the system equations in the presence of lognormal type of fading signal. Some analytical results for non-linear amplifier based conventional phase locked loop and charge pump phase locked loop are also incorporated to confirm the simulation results and for the choice of optimum design system parameter. <br/> <br/>Page(s): 310-316 http://nopr.niscair.res.in/handle/123456789/4083 Title: New low-voltage class AB current conveyor II for analog applications <br/> <br/>Authors: Manhas, Parshotam S; Pal, K; Sharma, Susheel; Mangotra, L K; Jamwal, K K S <br/> <br/>Abstract: Current conveyors are unity gain active elements exhibiting high linearity, wide dynamic range and high frequency performance than their voltage mode counterparts. The new current conveyor operating at low-voltage supplies high input impedance and low output impedance and consumes less power. In this study, a new low-voltage class AB second generation current conveyor (AB CCII) is presented which can be easily converted into CFAs, etc. PSpice simulation results verifying theoretical analysis are also incorporated. <br/> <br/>Page(s): 306-309 http://nopr.niscair.res.in/handle/123456789/4082 Title: Field dependent soft mode frequency in Ba_xSr_1-xTiO₃ferroelectric perovskites <br/> <br/>Authors: Kumar, Ashok; Kukreti, Ashish; Naithani, U C <br/> <br/>Abstract: An expression has been obtained for the soft mode frequency in Ba_xSr_1-xTiO₃ ferroelectric perovskites in the presence of external electric field, by using double time temperature dependent Green’s function technique. The mass and force constant change due to impurity atoms which are taken into account in the presence of higher order anharmonic and electric moment terms in the Silverman Joseph Hamiltonian. The soft mode frequency is obtained in the presence of both the electric field and impurity of Ba in an anharmonic SrTiO₃ ferroelectric perovskites. The soft mode frequency decreases with increase of impurity concentration of Ba in pure SrTiO₃. The soft mode frequency also increases with increase of external electric field in Ba_XSr_1-XTiO₃ ferroelectric perovskites.<b></b> <br/> <br/>Page(s): 300-305 http://nopr.niscair.res.in/handle/123456789/4081 Title: Effect of structural parameters on variation of microstructural and magnetic properties of nanocrystalline alloy of Fe_73.5Cu₁Nb₃Si_17.5B₅ <br/> <br/>Authors: Uddin, M M; Hoque, S Manjura; Mahmud, M Sultan; Hakim, M A; Chowdhury, F U Z <br/> <br/>Abstract: <smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="metricconverter"> Amorphous ribbons of Fe_73.5Cu₁Nb₃Si_17.5B₅ alloy have been annealed in the temperature range 475-700°C for X-ray diffraction (XRD) patterns. Crystallization induced by heat treatment resulted in the formation of a Fe-Si phase. The phase formed by primary crystallization has been found to be Fe-Si solid solution with a composition corresponding to disordered Fe-Si. Secondary crystallization of the Fe₃B and Fe₂B phases arises with the individual branches at the interfaces of the closely spaced crystals at the temperature 680°C, the spacing of such crystals was of the order of nanometer. Samples have been annealed in a controlled way in the temperature range 510-700°C with an interval of 10°C to 30°C for 1 h in order to study the effect of structural parameters of the nanocrystalline Fe(Si) grains on the variation of microstructural and soft magnetic properties. Temperature and frequency dependence of initial permeability of amorphous and devitrified toroid shaped samples have been measured. The permeability values showed little change as annealing time. Enrichment of Curie temperature has been observed for amorphous alloy due to the irreversible structural relaxation. The microstructures of the annealed samples are characterized as solid solutions of <i>bcc</i> Fe(Si) crystallites with grain sizes 5-19 nm and an abrupt increase 53 nm at 700°C. Silicon contents in the nanocrystalline phases determined from the lattice parameters are 12.67 to 15.48 At.%. The best magnetic properties have been observed when the annealing temperature is close to 575°C. Temperature dependence of real part of initial permeability of the annealed samples between the annealing temperature of 550°C and 575°C exhibits superparamagnetic/superferromagnetic behaviour at <i>T</i> ><b></b><i>T</i>_<i>c</i>^<i>am</i> </smarttagtype> <br/> <br/>Page(s): 289-299