Patent ID: 8604808

Claim:
An indicator position detecting device, comprising: a conductor pattern that is composed of a plurality of conductors disposed along a first direction and a plurality of conductors disposed along a second direction intersecting with the first direction, the conductor pattern being configured to detect position indication by an indicator; a multi-frequency signal supply circuit configured to supply N number of transmission signals at N different frequencies, respectively, selected from M number of different frequencies, to the plurality of conductors disposed along the first direction, where N and M are integers and M is greater than or equal to N; a frequency analyzing circuit configured to be supplied with reception signals from the plurality of conductors disposed along the second direction and to carry out frequency analysis of each of the reception signals for N number of frequency components corresponding to said N number of transmission signals at N different frequencies; an indicated-position detecting circuit configured to receive a result of the frequency analysis from the frequency analyzing circuit and to detect position indication by the indicator based on the received result of the frequency analysis; a noise analyzing circuit configured to detect noise components in the reception signals at the N different frequencies; and a control circuit configured to determine, based on the noise components detected by the noise analyzing circuit, whether the same set of the N different frequencies is to be supplied next or not from the multi-frequency signal supply circuit to the plurality of conductors disposed along the first direction.