Stylus switch status determination in a digitizer tablet having a cordless stylus
First Claim
1. A cordless pointing device for use with a position determining system, comprising:
- a switch having a manually changeable status; and
means for generating signals which the position determining system uses to determine the position of said pointing device relative to a surface of the position determining system and the status of said switch;
said signal generating means generating first and second signals at first and second different frequencies and a composite signal from said first and second signals which is receivable by the position determining system;
said signal generating means including means responsive to a change in status of said switch for altering a parameter of at least one of said first and second signals while maintaining a parameter of said composite signal substantially constant.
2 Assignments
0 Petitions
Accused Products
Abstract
A digitizer tablet with a cordless transducer which is capable of providing to the tablet information relating not only to the position of the pointing device but also with respect to the status of any button switches on the transducer. This is obtained by providing a plurality of oscillators, connected in circuits in which the relative ratio of the signal frequency outputs of the oscillators can be varied in response to activation of a switch while at the same time the sum of the amplitudes of the oscillating signals remain constant. Thus, the determination of the sum can be used as a indication of the position of the pointing device with respect to the tablet, whereas by determining the differences in the signal intensities of the different frequency oscillating signals, it is possible to determine the status of the button switches on the pointing device. The invention is typically used with a stylus or cursor driven tablet.
-
Citations
23 Claims
-
1. A cordless pointing device for use with a position determining system, comprising:
-
a switch having a manually changeable status; and means for generating signals which the position determining system uses to determine the position of said pointing device relative to a surface of the position determining system and the status of said switch;
said signal generating means generating first and second signals at first and second different frequencies and a composite signal from said first and second signals which is receivable by the position determining system;said signal generating means including means responsive to a change in status of said switch for altering a parameter of at least one of said first and second signals while maintaining a parameter of said composite signal substantially constant. - View Dependent Claims (2, 3)
-
-
4. A digitizing system comprising:
-
a digitizing tablet and a cordless pointing device, said cordless pointing device having a switch and signal generating means for generating signals used by said tablet to determine the position of said pointing device relative to said tablet and the status of said switch, said signal generating means comprising plural signal sources providing output signals at different signal frequencies, means for providing a sum signal which is the sum of the magnitudes of said output signals, and means for altering the relative magnitudes of said output signals without substantially altering the magnitude of said sum signal, the relative magnitudes of said output signals being related to the status of said switch, said pointing device including means for transmitting said sum signal to said tablet, and said tablet including means for receiving said sum signal from said cordless pointing device and determining therefrom the switch status and the position of said pointing device relative to said tablet. - View Dependent Claims (5, 6, 7, 8, 9)
-
-
10. A digitizing system comprising:
-
a digitizing tablet, and a pointing device free of any cable or electrical wire connection to the tablet, comprising means for generating a plurality of signals at a plurality of different frequencies, at least one switch connected to vary the magnitude of at least one of the plurality of signals upon a change in the status of the switch, means for combining the signals of different frequencies and means for radiating the combined signal to the tablet, said digitizing tablet comprising means for receiving the combined signal radiated by said radiating means, separating the received combined signal into signals corresponding to those generated at the different frequencies by said generating means and means for determining a change in magnitude of one of the signals, said change in magnitude being related to the status of said switch. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
-
-
22. A method of operating a digitizer tablet with a cordless pointing device having one or more switches to provide to the tablet information relating both to the position of the pointing device relative to the tablet and to the status of the switches on the pointing device, comprising:
-
providing first and second signals at different frequencies, coupling the pointing device switcher such that a change in status of a switch varies the relative magnitudes of the first and second signals, radiating the first and second signals from the pointing device in a given status of the switch, and detecting the first and second radiated signals and determining the status of the switch from the relative magnitudes of the detected signals. - View Dependent Claims (23)
-
Specification