Patent ID: 7440987
Filing Date: 2008-10-21
Classification: G06F

Abstract:
1. A trigonometric function generator to provide at least one output signal, each output signal representing one of a plurality of trigonometric functions in response to an input signal indicating an angle, said trigonometric function generator comprising: an angle decomposing circuit connected for receiving said input signal to separate said input signal into a plurality of decomposition signals representing sub-angles of said angle, a sum of said sub-angles equaling said angle; an interpolation circuit in communication with said angle decomposing circuit to receive one of said decomposition signals representing a smallest of said sub-angles for generating the trigonometric function signals representing the plurality of trigonometric functions for said smallest of said sub-angles by interpolating between the trigonometric functions of two known angles; a first angle trigonometric retaining circuit in communication with the interpolation circuit and the angle decomposing circuit for retaining the trigonometric functions of said known angles to communicate a first trigonometric function signal representing the trigonometric functions for said two known angles to said interpolation circuit, the angle decomposing circuit providing a first indicating signal selecting said two known angles and said two known angles being an adjacent larger known angle and an adjacent smaller known angle; at least one second angle trigonometric retaining circuit, each second angle trigonometric retaining circuit in communication with the angle decomposing circuit for retaining the trigonometric functions of for one of the sub-angles to communicate a second trigonometric function signal representing the trigonometric functions for said sub-angle upon receipt of a second indicating signal from the angle decomposing circuit denoting said sub-angle; and a complex arithmetic unit for combining the first trigonometric function signal and the second trigonometric function signal of each of the second angle trigonometric retaining circuits to create the output signals.