POSITION POINTER

摘要

PURPOSE:To simultaneously and individually detect positions pointed by plural tuning circuits by providing these tuning circuits and applying the alternate ON/OFF control at a prescribed interval to the switching means of the tuning circuits consisting of coils and capacitors. CONSTITUTION:A coil 12a and a capacitor 12b are connected in series to each other via a switching element 12c. Then a tuning circuit 12 of a frequency f0 is obtained when the element 12c is turned on. While a coil 13a and a capacitor 13b are connected in series to each other via a switching element 13c. Then a tuning circuit 13 of a frequency f1 is obtained when th element 13c is turned on. A switch driving circuit 14 applies the prescribed driving voltage alternately to both elements 12c and 13c for a prescribed period of time while the power is supplied from a battery 16 via a switch 15. Thus the elements 12c and 13c are turned on. Then the positions approximately equal to the centers of both coils 12a and 13a are detected by a tablet and a position detecting circuit. These positions undergo the coordinate transformation to the positions of indexes 17 and 18 via the data processing.