Method of fast arctangent calculation pre and post processing

A method of calculating an arctangent includes coding a sign for a y-value an x-value into a 3-bit index. When the absolute value of the x-value is greater than the absolute value of the y-value, the absolute values of the x-value and the y-value are swapped, and a swap bit of the index is coded to...

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1. Verfasser: RANSOM, RAY M
Format: Patent
Sprache:eng
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Zusammenfassung:A method of calculating an arctangent includes coding a sign for a y-value an x-value into a 3-bit index. When the absolute value of the x-value is greater than the absolute value of the y-value, the absolute values of the x-value and the y-value are swapped, and a swap bit of the index is coded to indicate that the x-value and the y-value were swapped. The arctangent is calculated from the quotient of the swapped x-value divided by the swapped y-value. A segment base angle is extracted from a table, based on the coded x-bit, y-bit, and swap bit of the index. An encoded sign is extracted from the segment base angle and is applied to the calculated arctangent output value to define a corrected arctangent value. The segment base angle is added to the corrected arctangent value to define the arctangent of the point.