CMOS Wide Tuning Gilbert Mixer with Controllable IF Bandwidth in Upcoming RF Front End for Multi-Band Multi-Standard Applications

The current global system for mobile communications, wireless local area, Bluetooth, and ultra-wideband demands a multi-band/multi-standard RF front end that can access all the available bandwidth specifications. Trade-offs occur between power consumption, noise figure, and linearity in CMOS Gilbert mixer wide tuning designs. Besides, it is preferable to have a constant IF bandwidth for different gain settings as the bandwidth varies with the load impedance when an RF receiver is tuned to a higher frequency. My dissertation consists of three parts. First, a tunable constant IF bandwidth Gilbert mixer is introduced for multi-band standard wireless applications such as 802.11 a/b/g WLAN and 802.16a WMAN, followed by a design synthesis approach to optimize the mixer to meet the design center frequency range, constant IF bandwidth, and power. A synthesized Gilbert mixer with effective prototype inductors, designed in 180 nm CMOS process, is presented in this dissertation with the tunability of 200 MHz IF, a constant IF bandwidth of 50 MHz, a conversion gain of 13.75 dB, a noise figure of 2.9dB, 1-dB compression point of -15.19 dBm, IIP3 of -5.8 dBm, and a power of 9 mW. Next, mixer inductor loss and equivalent electronic circuit analysis are presented to optimize the approach to offset center frequency and bandwidth inaccuracy due to the inductance loss between the actual and ideal prototype inductor. The proposed tunable Gilbert mixer simulations present a tunable IF of 177.8 MHz, an IF bandwidth of 87.57 MHz, a conversion gain of 7.4 dB, a noise figure of 3.14 dB, 1-dB compression point of -17.1 dBm, and IIP3 of -19.8 dBm. Last, a CMOS integrated wide frequency span CMOS low noise amplifier is integrated with the tunable Gilbert mixer to achieve a 27.68 dB conversion gain, a 3.47 dB low noise figure, -14.6 dBm 1-dB compression point, and -18.6 dBm IIP3

Large Deviations for Non-Markovian Diffusions and a Path-Dependent Eikonal Equation

This paper provides a large deviation principle for Non-Markovian, Brownian motion driven stochastic differential equations with random coefficients. Similar to Gao and Liu \cite{GL}, this extends the corresponding results collected in Freidlin and Wentzell \cite{FreidlinWentzell}. However, we use a different line of argument, adapting the PDE method of Fleming \cite{Fleming} and Evans and Ishii \cite{EvansIshii} to the path-dependent case, by using backward stochastic differential techniques. Similar to the Markovian case, we obtain a characterization of the action function as the unique bounded solution of a path-dependent version of the Eikonal equation. Finally, we provide an application to the short maturity asymptotics of the implied volatility surface in financial mathematics

Comparison of Viscosity Solutions of Semi-linear Path-Dependent PDEs

This paper provides a probabilistic proof of the comparison result for viscosity solutions of path-dependent semilinear PDEs. We consider the notion of viscosity solutions introduced in \cite{EKTZ} which considers as test functions all those smooth processes which are tangent in mean. When restricted to the Markovian case, this definition induces a larger set of test functions, and reduces to the notion of stochastic viscosity solutions analyzed in \cite{BayraktarSirbu1,BayraktarSirbu2}. Our main result takes advantage of this enlargement of the test functions, and provides an easier proof of comparison. This is most remarkable in the context of the linear path-dependent heat equation. As a key ingredient for our methodology, we introduce a notion of punctual differentiation, similar to the corresponding concept in the standard viscosity solutions \cite{CaffarelliCabre}, and we prove that semimartingales are almost everywhere punctually differentiable. This smoothness result can be viewed as the counterpart of the Aleksandroff smoothness result for convex functions. A similar comparison result was established earlier in \cite{EKTZ}. The result of this paper is more general and, more importantly, the arguments that we develop do not rely on any representation of the solution

A close phylogenetic relationship between Sipuncula and Annelida evidenced from the complete mitochondrial genome sequence of Phascolosoma esculenta

<p>Abstract</p> <p>Background</p> <p>There are many advantages to the application of complete mitochondrial (mt) genomes in the accurate reconstruction of phylogenetic relationships in Metazoa. Although over one thousand metazoan genomes have been sequenced, the taxonomic sampling is highly biased, left with many phyla without a single representative of complete mitochondrial genome. Sipuncula (peanut worms or star worms) is a small taxon of worm-like marine organisms with an uncertain phylogenetic position. In this report, we present the mitochondrial genome sequence of <it>Phascolosoma esculenta</it>, the first complete mitochondrial genome of the phylum.</p> <p>Results</p> <p>The mitochondrial genome of <it>P</it>.<it>esculenta </it>is 15,494 bp in length. The coding strand consists of 32.1% A, 21.5% C, 13.0% G, and 33.4% T bases (AT = 65.5%; AT skew = -0.019; GC skew = -0.248). It contains thirteen protein-coding genes (PCGs) with 3,709 codons in total, twenty-two transfer RNA genes, two ribosomal RNA genes and a non-coding AT-rich region (AT = 74.2%). All of the 37 identified genes are transcribed from the same DNA strand. Compared with the typical set of metazoan mt genomes, sipunculid lacks <it>trnR </it>but has an additional <it>trnM</it>. Maximum Likelihood and Bayesian analyses of the protein sequences show that Myzostomida, Sipuncula and Annelida (including echiurans and pogonophorans) form a monophyletic group, which supports a closer relationship between Sipuncula and Annelida than with Mollusca, Brachiopoda, and some other lophotrochozoan groups.</p> <p>Conclusion</p> <p>This is the first report of a complete mitochondrial genome as a representative within the phylum Sipuncula. It shares many more similar features with the four known annelid and one echiuran mtDNAs. Firstly, sipunculans and annelids share quite similar gene order in the mitochondrial genome, with all 37 genes located on the same strand; secondly, phylogenetic analyses based on the concatenated protein sequences also strongly support the sipunculan + annelid clade (including echiurans and pogonophorans). Hence annelid "key-characters" including segmentation may be more labile than previously assumed.</p