Online AMS frontend reconfiguration for sensor network applications and other continuously changing environments.

摘要

This thesis proposes a novel online analog and mixed-signal (AMS) frontend reconfiguration approach for sensor network applications and other continuously changing environments. The approach is based on a design point (DP) selection algorithm. The algorithm has two steps: DP sampling and DP pruning. This thesis also proposes a systematic methodology for reconfigurable DeltaSigma modulator topology designs.;The system software of traditional embedded system optimizes the allocation of a fixed set of resources under static conditions. However, the functionality and performance constraints of data processing systems are far less predictable since the characteristics of the monitored environment are continuously changing. In this thesis, the concept of developing AMS frontend design strategies for anticipative management of metadata acquisition, processing, and communication in dynamic environments is proposed. The idea is to develop mathematical models and small-overhead algorithms for online monitoring of performance requirements and comprehensive adaptation of embedded architecture for metadata processing.;While reconfigurable digital systems are very popular and well understood in terms of their capabilities and limitations, reconfigurable analog and mixed-signal (AMS) systems are, in contrast, much less studied or employed in practical applications. This prevents the more comprehensive harvesting of the possible benefits of reconfigurable systems, as a majority of embedded applications (e.g., embedded control and telecommunications) include significant amounts of analog signal processing. To address this major limitation, research must not only address new reconfigurable AMS architectural concepts, but also study the related design methodologies and EDA tools. More specifically, it is essential to develop efficient techniques for designing reconfigurable analog to digital converters (ADC) due to the importance of ADCs in embedded systems.;Reconfigurable systems simultaneously offer the advantages of (i) high performance processing, provided by hardware, and (ii) flexibility in tackling different applications, provided by software. Reconfigurable systems are attractive implementation platforms for many embedded applications due to their capability of offering low development costs and short design times, while being accessible to less experienced designers.;With the development of wireless communication technology, many wireless communication standards emerged, such as AMPS, GSM, CDMA, WCDMA, UMTS, etc. A wireless communication system which can efficiently support multiple communication standards led to the interest in developing a reconfigurable multi-mode receiver that can meet the band-width and resolution requirements of multiple standards. The most difficult part in implementing a reconfigurable multi-mode receiver is the design of a high performance, compact reconfigurable analog to digital convertor that will reconfigure the convertor topology when iv communication standard changes.;In this thesis, a methodology for designing reconfigurable discrete-time DeltaSigma modulator topologies is proposed. Optimized topologies are selected from the set of all possible topologies expressed by a generic topology, such that they (i) minimize the complexity of the topologies, (ii) maximize the topology robustness with respect to circuit nonidealities, and (iii) minimize the total power consumption. A case study of the design of topologies for a three-mode reconfigurable DeltaSigma modulator is presented. A reconfigurable topology implementation on a Programmable System-on-Chip (PSoC) device is also included.;This thesis presents a systematic methodology for producing reconfigurable DeltaSigma modulator topologies with optimized flexibility in meeting variable performance specifications. To increase their flexibility, topologies are optimized for performance attributes pertaining to ranges of values rather than being single values. Topologies are implemented on switched-capacitor reconfigurable mixed-signal architectures. Since the number of configurable blocks is very small, it is extremely important that the topologies use as few blocks as possible.;A case study illustrates the methodology for specifications from telecommunications area and a dynamic reconfiguration methodology of mixed-domain embedded systems for applications with variable performance requirements is introduced. A methodology for designing cost effective, dynamically reconfigurable, mixed-domain systems for metadata processing is proposed. During operation, the system switches between different design points for analog and digital blocks, depending on the actual performance needs. A case study for sound based tracking is discussed.;Sensor networks are increasingly important for many applications in environmental monitoring, manufacturing, defense and infrastructure monitoring. Many applications introduce variable performance requirements which demand online architecture reconfiguration, including the analog-digital frontends to sensors. In the last part, this thesis presents design automation methods for deciding the design points used for dynamic reconfiguration of analog-to-digital converters and DSP circuits.