High Level Circuit Design for Low Power Audio Signal Processing

Our goal in the PRO-DASP project within the DFG priority program VIVA has been the development of a rapid-prototyping environment for functional verification and test of digital signal processing algorithms. We have realized a power-optimised technology independent macro-module library to support a fast and efficient design methodology. The library is embedded into a design-framework which supports an easy high-level data-flow oriented construction of signal processing algorithms using abstract function prototypes and allows an automatic optimisation and verification. The macros implement a variety of architectural and algorithmic transformations for DSP-functions as well as basic arithmetic components. Our approach differs from existing high-level low-power synthesis tools mainly in two points: Firstly, the framework embodies a psychoacoustically motivated measurement of the output signal quality to ensure that the signal processing does not distort the signal beyond a limit while allowing transformations affecting the overall signal quality. Secondly, by defining hierarchy-levels for all modules, we can combine high level transformations for complex operations like filters with a set of basic arithmetic macros implementing various number representations and number systems like sign-magnitude, two's-complement or fixedand floating point numbers and logarithmic and residue number systems.