| 摘要 |
PURPOSE:To read a cursor position with high image resolution without decreasing the read speed, by dividing an electric conductor loop into plural loop groups, and driving them in order and also selectively only a specified loop group. CONSTITUTION:Plural electric conductor loops 211 and 216 are provided on the surface of an insulating plate 20 so as to have a single pole. Electromotive force of a cursor 30 is amplified by an amplifier 32 through a tuning circuit 31, afterwards, is led to a polarized detector 33 and a band pass filter 34. A point which crosses zero of a fundamental wave is situated on a position being 90 deg. out-of- phase from a position of the cursor 30, a generated energizing signal on this point is applied to a counter 35 from a switching circuit 40, as a start pulse, and its counting operation is started. An output clock of an oscillator 26 is divided by a frequency divider 27, is fed to the switching circuit 40, is divided by a frequency divider 28, and is sent to the switching circuit 40. A peak detector 50 reads a peak value of voltage based on electromotive force generated in a coil 30, and detects a loop group of the part where the coil 30 is positioned. |
