DS.13 IMPROVED ACCURACY FOR LOGARITHMIC AQDITION IN DSP APPLICATIONS
Mark G. Arnold, John Cowles, Thomas A. Bailey · 1988
Logarithmic number systems are an attractive method of implementing high speed digital signal processing systems with a word size of about 14 bits. Larger word sizes pose problems because of the address limitations of the ROMs needed for logarithmic addition. Arnold gave several interpolation techniques that can double the precision, but these techniques require the use of a fixed point multiplier. Taylor proposed a modified linear interpolation method that could increase the precision by about four bits without using a multiplier. It is shown here that an improvement can be mde in Taylor's technique by choosing a different constant. Also by combining one of Arnold's techniques with a variant of Taylor's modification, precision similar to that of Taylor's design can be obtained using a simpler circuit.