Symbolic Extraction for Estimating Analog Layout Parasitics in Layout-Aware Synthesis

This paper presents a new layout parasitics extraction paradigm, symbolic extraction, for use in layout-aware analog synthesis methodologies. Unlike traditional post-layout extraction, symbolic extraction extracts layout parasitics in symbolic form from parameterized layouts. As a result, parasitic values can be calculated directly from given circuit and layout parameters. In layout-aware circuit synthesis process, tasks of time-consuming layout re-gerenarion and re-extraction can be replaced by this fast parasitics calculation step. In the paper, we discuss how to integrate symbolic extraction into the existing analog design flow and how symbolic extraction can be implemented

Towards Reduced-Order Models for Online Motion Planning and Control of UAVs in the Presence of Wind

Abstract This paper describes a model reduction strategy for obtaining a computationally efficient prediction of a fixed-wing UAV performing waypoint navigation under steady wind conditions. The strategy relies on the off-line generation of time parametrized trajectory libraries for a set of flight conditions and reduced order basis functions functions for determining intermediate locations. It is assumed that the UAV has independent bounded control over the airspeed and altitude, and consider a 2D slice of the operating environment. We found that the reduced-order model finds intermediate positions within 10% and at speeds of 10x faster than clock-time (even in wind conditions in excess of 50% of the UAV's forward airspeed) when compared against simulation results using a medium-fidelity flight dynamics model. The potential of this strategy for online planning operations is highlighted

Experimental investigation of interface states and photovoltaic effects on the scanning capacitance microscopy measurement for p-n junction dopant profiling

Controlled polishing procedures were used to produce both uniformly doped and p-n junction silicon samples with different interface state densities but identical oxide thicknesses. Using these samples, the effects of interface states on scanning capacitance microscopy (SCM) measurements could be singled out. SCM measurements on the junction samples were performed with and without illumination from the atomic force microscopy laser. Both the interface charges and the illumination were seen to affect the SCM signal near p-n junctions significantly. SCM p-n junction dopant profiling can be achieved by avoiding or correctly modeling these two factors in the experiment and in the simulation. (c) 2005 American Institute of Physics

Architecture of wireless sensor node using novel ultra-wideband modulation scheme

Recently ultra-wideband (UWB) communications has emerged as an alternative to narrowband communications used in wireless sensor networks. One of UWB(s) most attractive feature for wireless sensors is that it can produce high data throughput rates at lower transmission power levels compared to narrow band wireless systems. Current UWB communication systems use narrow time pulse sequences to transmit information. This paper presents a wireless sensor node architecture that uses a novel UWB data modulation scheme based on pulse shaping. In this paper, the advantages and hardware requirements of the pulse shaping modulation system are compared against a conventional UWB system. The pulse shaping modulation scheme adds more flexibility for data modulation in UWB communication systems. The modulation scheme encodes data in both the timing and frequency spectrum of the transmitted pulse. This will lower interference between UWB and narrowband systems and allow for robust communications to be used by a large number of sensors in a small area

Novel ultra-wideband pulse spectrum modulation scheme

Current ultra-wideband communication systems use short narrow timed pulse sequences to transmit information. Some disadvantages of UWB communication systems are its interference of other conventional wireless systems and its reliance on time hopping schemes for multiple access. This paper presents a novel UWB data modulation scheme based on pulse shaping. This modulation scheme adds more flexibility for data modulation in UWB communication systems. The modulation scheme encodes data in both the timing and frequency spectrum of the transmitted pulse. This has the potential to improve data throughput rates and to lower interference between UWB and narrowband systems