Method and active stylus for generating signal, method and touch screen for analyzing signal

A method for analyzing a signal with a touch screen, comprising:

• recognizing, by the touch screen, a plurality of encoded frequency-modulated signals and a fixed-frequency signal for detecting a stylus tip position from a received encoded signal, wherein the encoded signal is generated by the active stylus by using a method for generating a signal;
• performing, by the touch screen, frequency demodulation on the plurality of encoded frequency-modulated signals to obtain n-bit q-ary codes that correspond to the plurality of encoded frequency-modulated signals, respectively;
• wherein q is an integer greater than 2;
• obtaining, by the touch screen, information that corresponds to the n-bit q-ary codes according to a preset correspondence between n-bit q-ary codes and the information;
• performing, by the touch screen, amplitude demodulation on the fixed-frequency signal for detecting a stylus tip position to obtain a demodulation amplitude of the fixed-frequency signal for detecting a stylus tip position;
• and
• calculating, by the touch screen, a stylus tip position of the active stylus according to the demodulation amplitude;
• wherein the method for generating a signal comprises:
• encoding, by the active stylus, information into n-bit q-ary codes;
• performing, by the active stylus, frequency modulation on the n-bit q-ary codes, respectively, to generate a plurality of encoded frequency-modulated signals;
• and
• combining, by the active stylus, a fixed-frequency signal for detecting a stylus tip position with the plurality of encoded frequency-modulated signals to form an encoded signal.