Adaptive self-calibrating image rejection receiver

An adaptive self-calibrating image rejection receiver is described, containing a modified Weaver image rejection mixer and a Digital Image Rejection Processor (DIRP). The blind source-separation-based DIRP eliminates the I/Q errors improving the Image Rejection Ratio (IRR) without the need for trimming or use of power-hungry discrete components. Hardware complexity is minimal, requiring only two complex coefficients; hence it can be easily integrated into the signal processing path of any receiver. Simulation results show that the proposed approach achieves 75-97 dB of IRR.

A low-complexity self-calibrating adaptive quadrature receiver

In this paper digital part of a self-calibrating quadrature-receiver is described, containing a digital calibration-engine. The blind source-separation-based calibration-engine eliminates the RF-impairments in real-time hence improving the receiver's performance without the need for test/pilot tones, trimming or use of power-hungry discrete components. Furthermore, an efficient time-multiplexed calibration-engine architecture is proposed and implemented on an FPGA utilising a reduced-range multiplier structure. The use of reduced-range multipliers results in substantial reduction of area as well as power consumption without a compromise in performance when compared with an efficiently designed general purpose multiplier. The performance of the calibration-engine does not depend on the modulation format or the constellation size of the received signal; hence it can be easily integrated into the digital signal processing paths of any receiver.

Cyborg Subjects: Discourses on Digital Culture

This book is an interrogation of humanity's new potentials and threats brought by technology when the question of social change is becoming more crucial than ever. Collected in the course of 2010-2012, the selected essays in this anthology confront questions from a wide-ranging perspective that evoke the postmodern idea of the cyborg to illuminate recent phenomena from global warming, Wikileaks, to the Occupy movements. Multiple disciplines from music to psychoanalysis to journalism to anthropology collaborate to examine the way we shape the world from behind our ubiquitous screens to taking to the streets in mass protests. What does the increasing omnipotence of networked machines ultimately mean? What do social networks do to our sense of self, others and society? Does P2P technology foster new ethics and spiritualities? What potentials does posthumanity have to bring about social change? Featuring essays from Robert Barry, Siri Driessen & Roos van Haaften, Bonni Rambatan, Dustin Cohen, Jacob Johanssen, Michel Bauwens, Aliki Tzatha, Zakary Paget, Stefen Baack, Alessandro Zagato, Peter Nikolaus Funke, Glenn Muschert, and Jung-Hua Liu.

Securing the Anthropocene? International Policy Experiments in Digital Hacktivism: A Case Study of Jakarta

This article analyses security discourses that are beginning to self-consciously take on board the shift towards the Anthropocene. Firstly, it sets out the developing episteme of the Anthropocene, highlighting the limits of instrumentalist cause-and-effect approaches to security, increasingly becoming displaced by discursive framings of securing as a process, generated through new forms of mediation and agency, capable of grasping inter-relations in a fluid context. This approach is the methodology of hacking: creatively composing and repurposing already existing forms of agency. It elaborates on hacking as a set of experimental practices and imaginaries of securing the Anthropocene, using as a case study the field of digital policy activism with the focus on community empowerment through social-technical assemblages being developed and applied in ‘the City of the Anthropocene’: Jakarta, Indonesia. The article concludes that policy interventions today cannot readily be grasped in modernist frameworks of ‘problem solving’ but should be seen more in terms of evolving and adaptive ‘life hacks’.