Touch sensitive processing apparatus and system for despreading and method thereof

A touch sensitive system for despreading and for rapid recognition of approaching styluses, comprising:

• a touch sensitive screen, comprising a plurality of first electrodes being parallel to a first axis and a plurality of second electrodes being parallel to a second axis;
• and
• a touch sensitive processing apparatus, connected to the plurality of first electrodes and the plurality of second electrodes, the touch sensitive processing apparatus, comprising an analog switch or a digital adder, configured to perform the following steps comprising:
• coupling at least two of the plurality of second electrodes as a synchronization channel for achieving rapid detection rate and allow simultaneous detection of multiple styluses, wherein said coupling is implemented by the analog switch or the digital adder;
• despreading a first preamble code of a first signal frame of received signal from the synchronization channel to retrieve a first synchronization information according to a first pseudo noise code, wherein the first signal frame is from a first active stylus approaching the touch sensitive screen;
• decoding a first data code behind the first preamble code of received signal from at least one of the plurality of first electrodes in accordance with the first synchronization information and the first pseudo noise code in order to receive information from the first active stylus;
• despreading a second preamble code of a second signal frame of received signal from the synchronization channel to retrieve a second synchronization information according to a second pseudo noise code, wherein the second signal frame is from a second active stylus approaching the touch sensitive screen;
• and
• decoding a second data code behind the second preamble code of received signal from at least one of the plurality of first electrodes in accordance with the second synchronization information and the second pseudo noise code in order to receive information from the second active stylus.

A touch sensitive processing apparatus for despreading and rapid recognition of approaching styluses, connected to a plurality of first electrodes being parallel to a first axis and a plurality of second electrodes being parallel to a second axis on a touch sensitive screen, the touch sensitive processing apparatus, comprising an analog switch or a digital adder, configured to perform the following steps comprising:

• coupling at least two of the plurality of second electrodes as a synchronization channel for achieving rapid detection rate and allow simultaneous detection of multiple styluses, wherein said coupling is implemented by the analog switch or the digital adder;
• despreading a first preamble code of a first signal frame of received signal from the synchronization channel to retrieve a first synchronization information according to a first pseudo noise code, wherein the first signal frame is from a first active stylus approaching the touch sensitive screen;
• decoding a first data code behind the first preamble code of received signal from at least one of the plurality of first electrodes in accordance with the first synchronization information and the first pseudo noise code in order to receive information from the first active stylus;
• despreading a second preamble code of a second signal frame of received signal from the synchronization channel to retrieve a second synchronization information according to a second pseudo noise code, wherein the second signal frame is from a second active stylus approaching the touch sensitive screen;
• and
• decoding a second data code behind the second preamble code of received signal from at least one of the plurality of first electrodes in accordance with the second synchronization information and the second pseudo noise code in order to receive information from the second active stylus.