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发表于 2014-12-25 10:00:02
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Advances in IC processing technology offer system designers the possibility of integrating complex, mixed analog/digital systems on a chip, leading to better reliability, performance and lower system cost. A very important problem mixed-signal designers are facing, is the lack of toot support for the design of the analog part in mixed-signal systems. Very often analog design is still done in the traditional way: manually, with no tools except SPICE, in a bottom-up way and with very little reuse of previous work. This lack of analog design tools leads to a very large mismatch between design times of the digital and the analog parts on mixed-signal ASICS. Analog design productivity can be increased by the development of automated tools for the low-level analog design supported by interactive high-level CAD tools. Past research in analog design automation has been focused mainly on the lower-level analog design tasks. In this work the emphasis is on the mixed-signal system level and on the higher The mixed-signal system-level design environment should support interactive system partitioning and design exploration by providing a fast evaluation of the quality of a proposed system-level solution. After this interactive system-level design, separate "slice compilers" can synthesize the different subsystems (e.g. an analog subsystem and digital subsystems for DSP and control).
For the analog subsystem a systematic hierarchical top-down design methodology distinguished: the architectural level, the block level and the transistor level. A general methodology for analog high-level design, i.e. the transition from the architectural level to the block level, is presented. In the analog domain, developing a functionally correct architecture is often rather straightforward, but deriving optimal block specifications, taking into account the different sources of nonideal second-order behavior, is a more critical problem. An optimization-based methodology for high-level specification translation is presented. If the architectural design problem (e.g. for analog-digital partitioning) can be described as the selection of a number of parameters in a generic parameterized architecture, then the architecture selection can be performed in the same optimization run as the specification translation.
The proposed methodologies are applied to the design of analog sensor interfaces and RF transceiver front-ends. For the behavioral performance evaluation of transceiver front-end architectures a dedicated frequency-domain analysis tool is presented. The signals are modeled as stochastic processes and are represented by their power spectral densities. The most important front-end nonidealities that cause signal quality degradation are included in the performance evaluation. For the efficient and accurate analysis of distortion spectra in wideband (multicarrier) analog transceiver front-end blocks, a new methodology is presented based on normal zero-mean stochastic processes. |
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