COORDINATE DETECTOR

PURPOSE:To improve positional precision by connecting a loop (large loop) constituted of a pair of coordinate detecting electric wires to a signal detection circuit as switching it by the width of a single loop, and deciding a coordinate according to the change and the size of a signal from the signal detection circuit. CONSTITUTION:A CPU 5 switch-controls each selector switch 4a, 4b, and simultaneously, decides whether the signal is present or absent in the large loop being switch-connected to the signal detection circuit 3 at that time, and in the case of presence, it stores successively data corresponding to the position of the large loop in a RAM 5c. The decision of the presence or the absence of the signal is performed on the basis of whether the output value of a peak hold circuit 3f at each switch-connecting position of the switches 4a, 4b exceeds reference voltage or not. A switching method is as follows. Namely, at first, the large loop position (a) to (b) of a comb-shaped electrode 1 is detected, and next, (b) to (c), and next, (d) to (e) is detected. By switching the large loop by the width of the single loop in this way, it can be found that a coordinate indicating pen 2 is located at the loop position (c). Similar detection is executed for Y axis, and finally, result is outputted as two-dimensional coordinate values.