Mutual capacitive touch-sensitive apparatus and method applying inverse signals to electrodes

A touch-sensitive apparatus, the apparatus comprising:

• a plurality of drive electrodes, comprising at least a first electrode and a second electrode;
• at least one receiver electrode;
• drive circuitry configured to generate a first time-varying voltage signal and a second time-varying voltage signal, wherein the first and second time-varying voltage signals are the inverse of one another;
• and
• control circuitry configured to:
• perform a first measurement on the at least one receiver electrode during a first time period, wherein the control circuitry is configured to supply at least one of the first and second time-varying voltage signals to the first and second drive electrodes during the first time period;
• perform a second measurement on the at least one receiver electrode during a second time period, wherein the control circuitry is configured to supply at least one of the first and second time-varying voltage signals to the first and second drive electrodes during the second time period;
• and
• determine a resultant signal corresponding to the mutual capacitance between the first electrode and the at least one receiver electrode based on both the first measurement and the second measurement,
• wherein the plurality of drive electrodes is divided into groups of drive electrodes consisting of N drive electrodes, and wherein, when the plurality of electrodes divided by N is not equal to an integer, the control circuitry is configured to include at least one drive electrode in two groups;
• and
• wherein in at least one of the first time period and the second time period, the control circuitry is configured to supply the first time-varying voltage signal, or the second time-varying voltage signal, to the at least one drive electrode included in the two groups, and to supply the other of the first time-varying voltage signal or the second time-varying voltage signal to at least one other drive electrode of at least one of the two groups.