Direct sampling receivers for broadband communications

Today everything tends to be connected in the Internet of Things (IoT) universe, where a broad variety of communication standards and technologies are used for those connected devices. It is always a dream to design a Software-Defined Radio (SDR) supporting different standards solely based on the software configuration. As integrated-circuit (IC) manufacture and design advance, a partial of SDR can be realized. This thesis investigates one of the most important parts in a SDR: the analog design of a direct sampling (DS) receiver, which mainly consists of a broadband RF front end and a wideband ADC. Especially, a DS receiver shows a great flexibility and efficiency for the simultaneous reception of multiple channels comparing with the traditional parallelism of superheterodyne structure. The research contributions of this work include (1) demonstration and comparative analysis of two new architectures of broadband RFPGAs: voltage-mode: RFPGA-V and current-mode: RFPGA-I. RFPGA-V and RFPGA-I utilize an innovative interpolation method and current steering approach, respectively, to achieve a fine gain step of 0.25-dB over 40-dB gain range for several GHz frequency range. Besides, with innovative design, no off-chip inductor is needed for the both RFPGAs. (2) The design of a 5-GS/s 10b time-interleaved SAR. The ADC power efficiency is significantly improved by many design techniques: the low-energy CDAC switching scheme, optimized input common-mode voltage for comparator, optimal reduced radix-2 capacitor ratio for low-power reference buffers and higher conversion speed, etc. The lane-to-lane mismatches in a time-interleave ADC are minimized by using optimal floor plan and then are calibrated digitally. Three prototypes: the broadband RF front ends with RFPGA-V, the broadband RF front ends with RFPGA-I and a 5-GHz ADC, are fabricated to verify the proposed ideas in 28nm CMOS technology.Electrical and Computer Engineerin

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference