Touch sensitive processing apparatus, system and operating method thereof for receiving electrical signals carrying pressure information

A method for receiving electrical signals carrying pressure information transmitted from a first stylus, comprising:

• receiving the electrical signals via electrodes of a touch panel;
• despreading a first preamble code of the electrical signals received in a first time period in accordance with a PN code;
• despreading a second preamble code of the electrical signals received in a second time period in accordance with the PN code;
• and
• calculating the pressure information according to a first signal strength ratio of a first part of the received electrical signal and a second part of the received electrical signal, wherein the first part comprises the first preamble code and the second part comprises the second preamble code.

A touch system, comprising:

• a touch panel;
• a first stylus;
• and
• a touch sensitive processing apparatus for receiving electrical signals carrying pressure information transmitted from the first stylus, comprising:
• a sensing circuit, configured for receiving the electrical signals via electrodes of the touch panel;
• and
• a processor, coupled to the sensing circuit, configured for:
• despreading a first preamble code of the received electrical signals in accordance with a PN code in a first time period;
• despreading a second preamble code of the received electrical signals in accordance with the PN code in a second time period;
• and
• calculating the pressure information according to a first signal strength ratio of a first part of the received electrical signal and a second part of the received electrical signal, wherein the first part comprises the first preamble code and the second part comprises the second preamble code.