Manuel F. Richey

A new class of floating-point data formats with applications to 16-bit digital-signal processing systems

Sixteen-bit, programmable, digital-signal processors suffer from inadequate dynamic range and noise performance due in part to the use of standard data formats with few bits available for numeric precision. A solution to this problem is developed that involves the use of irregular data formats. A new class of irregular floating-point formats is developed. A specific format is derived from this class that provides greater dynamic range and improved noise performance for 16-bit DSP applications. An experiment with one of the new formats is conducted and analyzed, and improved performance is verified. The importance of our work and its potential applications are discussed.

Compressed fixed-point data formats with non-standard compression factors

Sign bit compression in fixed-point numbering systems can improve the dynamic range and round-off noise for signal processing algorithms. This paper analyses non-standard compression factors (CF) for compressed fixed-point data formats, where sign bit compression is performed on each individual fixed-point number. Although these compression techniques are applicable to other fixed-point formats, the compressed twos complement data format is selected for illustration. A brief background on compressed twos complement is provided. Obvious compression factors are powers of two due to binary formatting, but compression factors other than standard powers of two are presented. Compression factors of 3 and 5 are analysed in greater detail. Motivation for and advantages of non-power-of-two compression factors are identified.

Compressed Two's Complement Data Formats Provide Greater Dynamic Range and Improved Noise Performance [exploratory DSP]

In this article, we present and analyze a new family of fixed-point data formats for signal processing applications. These formats represent compressed twos complement data formats where compression on the sign bit is undertaken on a sample by sample basis. The extra room provided by sign-bit compression is utilized to retain more bits of precision for each individual sample. Compressed twos complement data formats are shown to provide greater dynamic range and improved noise performance over traditional fixed-point data formats such as sign-magnitude, offset binary, and traditional twos complement. Traditional twos complement is shown to be a member of the compressed twos complement family where the compression factor (CF) is equal to one. The dynamic range of a compressed twos complement data format is shown to approach the dynamic range of a non compressed data format raised to the power of the CF. Improved performance for digital signal processing (DSP) applications such as digital filters and transforms is presented for specific instances of this family.