Circuits, systems, and methods implementing approximations for logarithm, inverse logarithm, and reciprocal

摘要

A digital signal system (30) for determining an approximate logarithm of a value of x having a base b is described. The system comprises circuitry for storing x as a digital representation, identifying a most significant digit (MSD) of the digital representation, a table for storing a set of predetermined logarithms having the base b, circuitry for addressing the table in response to a first bit group (t) of the set of bits in respective lesser significant bit locations and for outputting a one of the predetermined logarithms corresponding to a first number (l_a) in the set of numbers, and circuitry for outputting the approximate logarithm of the value of x in response to the one of the predetermined logarithms and in response to a function estimation between logarithms at a first and second endpoint.