The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 11, 1992
Filed:
May. 06, 1991
Gregory F Russell, Yorktown Heights, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
An inductive pen (16) repetitively transmits pulses of an oscillatory signal having a characteristic frequency. Pen state information, such as pen tip contact switch information, are encoded by a number of techniques. These techniques include pulse width modulation or pulse position modulation, so as to convey pen state information to a digitizing tablet in a manner that does not adversely affect pen position determinations. The pen state information may also be encoded on the oscillating signal by Frequency Shift Keying (FSK), Phase Shift Keying (PSK), or Amplitude Modulation (AM). A digitizer tablet (10) includes circuitry for detecting the transmitted pen state information, the circuitry accommodating the selected modulation scheme. The tablet is responsive to the transmitted pulses for placing tablet circuitry in a low-power consumption state between pulses so as to conserve tablet power.