Gazelle Graphic Systems Inc.

Logitech, Inc.

Michael N Gilano

Anthony Edward Zank

Kenneth S Gold

H Maurice France

Electromagnetic position transducer having active transmitting stylus

Disclosed is electromagnetic transducer that does not require complex analog to digital, digital to analog converters, microprocessors or large memory circuitry. The transducer has a helical tablet coil with tap nodes spaced between its end extremities. In one configuration, an oscillator drives the tablet coil for simultaneously producing oppositely directed currents on opposite sides of selected taps, creating a moving fringing field that is compatible with modern graphic display tablet technology. A control circuit of the transducer has a closed-loop integrator for detecting the centroid of a received stylus signal from a stylus coil. Analog and digital versions of the integrator are disclosed. In another configuration, the oscillator drives the stylus coil for variably coupling magnetic flux to the tablet coil, a receiver signal that is coupled from the end extremities being responsive to the position of the stylus coil and the taps selected. A preferred configuration of the tablet coil has separate oppositely wound coil components.

Disclosed is electromagnetic transducer that does not require complex analog to digital, digital to analog converters, microprocessors or large memory circuitry. The transducer has a helical transmitter coil with tap nodes spaced between its end extremities. An oscillator drives the coil for simultaneously producing oppositely directed current on opposite sides of selected taps, creating a moving fringing field that is compatible with modern graphic display tablet technology. A control circuit of the transducer has a closed-loop integrator for detecting the centroid of a received stylus signal. Analog and digital versions of the integrator are disclosed.

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Irvine, CA, United States of America

Michael N Gilano