Inventors:
Sen W. Chu - Torrance CA
Milos D. Ercegovac - Los Angeles CA
Kenneth A. Essenwanger - Walnut CA
Tomas Lang - Irvine CA
Allen L. S. Sakai - Laguna Niguel CA
Assignee:
Raytheon Company - Lexington MA
International Classification:
G06F 100
Abstract:
A digital phase to digital sine and cosine amplitude translator generates sine and cosine outputs from an input angle word, which is decomposed into the most significant bits (MSBs) and the least significant bits (LSBs), and the octant number of the angle is identified by the octant identifier bits. Radix-4 multiplier/adder circuits improve the efficiency of multiplication/addition computations. An incrementor and a decrementor are used for sine and cosine MSB computations, respectively, to further save the computer memory and logic. In a preferred embodiment, the MSBs of the sine and cosine outputs for all octants are generated based upon the octant number of the input angle, and the LSBs of the outputs are generated by trigonometric approximations and octant selection, thereby resulting in a savings in computer memory and logic.