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# Angular Position Determining Means

IP.com Disclosure Number: IPCOM000084946D
Original Publication Date: 1976-Feb-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 55K

IBM

## Related People

Gambrel, DR: AUTHOR

## Abstract

Using analog input voltages where a first input (V1) and a second input (V2) are of the form V1=Vm SIN X and V2=Vm COS X. an analog-to-digital (A/D) converter may be provided that provides a digital word to the computer which includes three bits of octant information and six bits of either TAN X or COT X information.

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Angular Position Determining Means

Using analog input voltages where a first input (V1) and a second input (V2) are of the form V1=Vm SIN X and V2=Vm COS X. an analog-to-digital (A/D) converter may be provided that provides a digital word to the computer which includes three bits of octant information and six bits of either TAN X or COT X information.

Hardware is minimized by not converting actual angle X information. This is avoided by using the computational ability of the computer to calculate X, given TAN X or COT X and the octant from the analog-to-digital converter. A six-bit conversion of the TAN X or COT X function allows the angle X to be determined to a resolution of better than one degree. If higher resolution is desired, the A/D converter can be extended which would incur some increased cost and complexity.

The conversion of TAN X or COT X represents a ratio of the two inputs such as: TAN X = V1/V2= Vm SIN X/Vm COS X = SINX X/COS X.

This eliminates the need to develop any knowledge regarding Vm which is generally not an accurate value.

As above indicated, the digital output of the converter has a 3-bit octant information field and an n-bit field (6 bits as described above) representing the conversion of either TAN X or COT X within that octant.

The octant is selected in accordance with the following table:

OCTANT SIN X>0 COS X>0 3COS X3>3SIN X3 N

0-45 degrees 1 1 1 TAN X 45-90 degrees 1 1 0 COT X 90-135 degrees 11 0 0 COT X 135-180 degrees 1 0 1 TAN X...