Multi-standard programmable baseband modulator for next generation wireless communication

Considerable research has taken place in recent times in the area of parameterization of software defined radio (SDR) architecture. Parameterization decreases the size of the software to be downloaded and also limits the hardware reconfiguration time. The present paper is based on the design and development of a programmable baseband modulator that perform the QPSK modulation schemes and as well as its other three commonly used variants to satisfy the requirement of several established 2G and 3G wireless communication standards. The proposed design has been shown to be capable of operating at a maximum data rate of 77 Mbps on Xilinx Virtex 2-Pro University field programmable gate array (FPGA) board. The pulse shaping root raised cosine (RRC) filter has been implemented using distributed arithmetic (DA) technique in the present work in order to reduce the computational complexity, and to achieve appropriate power reduction and enhanced throughput. The designed multiplier-less programmable 32-tap FIR-based RRC filter has been found to withstand a peak inter-symbol interference (ISI) distortion of -41 dB

On Radiative Acceleration of Jets and Outflows from Advective Disks

Jets and outflows are known to form out of advective accretion flows around black holes. Hard photons from the centrifugal barrier directly hit the electrons and deposit momentum on them. For optically thick flows such deposition is not efficient, but for optically thin flows matter could be accelerated to relativistic speed. In fact, even bound matter could be made free through successive deposition. We discuss these possibilities.Comment: AIP Publication, Macro include

Massloss from viscous advective disc

Rotating transonic flows are long known to admit standing or oscillating shocks and that the excess thermal energy in the post shock flow drives a part of the infalling matter as bipolar outflows. We compute massloss from a viscous advective disc. We show that the mass outflow rate decreases with increasing viscosity of the accretion disc, since viscosity weakens the centrifugal barrier that generates the shock. We also show that the optical depth of the post-shock matter decreases due to massloss which may soften the spectrum from such a mass losing disc.Comment: 14 pages, 7 figures, accepted in New Astronom

Local governance: Bureaucratic performance and health care delivery in Calcutta.

This thesis is based on a comparative case study of two bustee neighbourhoods located in two separate wards of Calcutta, and of the factors which have affected the performance of public officials providing primary health care services to their inhabitants. It is argued that poor bureaucratic performance and a lack of accountability lie at the heart of problems with the health system in West Bengal. The thesis evaluates the effectiveness of 'governance' reforms, comprising decentralisation and the application of the principles of New Public Management (NPM), on the performance of public officials. NPM and decentralisation apply the core assumptions of neo-classical economics to the study of bureaucratic decision-making. The thesis argues that local officials in Calcutta may not always have chosen to behave in a way which maxmised their personal welfare, but that history, culture and politics may have affected the choices that they made. The thesis questions the view that decentralization necessarily leads to greater community participation challenges contemporary notions of what constitutes 'civil society' and suggests a more nuanced view of the relationship between civil society and good government. It questions NPM's claims to universality, which have resulted in its widespread application without due regard to local context, and argues that NPM inspired reforms have had a limited effect on health officials in Calcutta, in part, because of their failure to address the underlying causes of poor bureaucratic performance. The final chapter argues that the political influence of public sector workers has affected the willingness of the ruling Party to enforce the incentives to improve the performance of health care officials in West Bengal