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High Speed Optical Syncro Encoder

IP.com Disclosure Number: IPCOM000088474D
Original Publication Date: 1977-Jun-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Sparrow, WR: AUTHOR

Abstract

A high-speed optical syncro encoder consists of three phototransistors 11, 13 and 15 placed at 120 Degrees around the axis of the rotating shaft 17. A movable (for calibration purposes) polarized glass 19 is placed adjacent a second section of polarized glass 21 attached to shaft 17. Three light-emitting diodes 23, 25 and 27 are aligned with the phototransistors 11, 13 and 15. Rotation of the movable polarizer 21 causes an increase and decrease in transmitted light at two times the shaft RPM. At each phototransistor, phase rotation depends upon the direction of shaft rotation. The output of each phototransistor is coupled to an operational amplifier 29, 31, 33 to establish a zero volt line and to aid in balancing the outputs. The resultant output signal is a three phase signal at two times shaft speed.

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High Speed Optical Syncro Encoder

A high-speed optical syncro encoder consists of three phototransistors 11, 13 and 15 placed at 120 Degrees around the axis of the rotating shaft 17. A movable (for calibration purposes) polarized glass 19 is placed adjacent a second section of polarized glass 21 attached to shaft 17. Three light-emitting diodes 23, 25 and 27 are aligned with the phototransistors 11, 13 and 15. Rotation of the movable polarizer 21 causes an increase and decrease in transmitted light at two times the shaft RPM. At each phototransistor, phase rotation depends upon the direction of shaft rotation. The output of each phototransistor is coupled to an operational amplifier 29, 31, 33 to establish a zero volt line and to aid in balancing the outputs. The resultant output signal is a three phase signal at two times shaft speed. The device can be used in areas requiring compactness and high speed detecting.

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