Patent ID: 9378724
Filing Date: 2016-06-28
CPC Classification: G10K,H04B

Claim Text:
1. A method for implementing near field communication (NFC), the method comprising: modulating a digital signal to generate an audio signal with a transmitting device by utilizing a binary frequency shift keying (2FSK) modulation scheme; playing the generated audio signal by the transmitting device; receiving the audio signal by a receiving device; sampling the audio signal by the receiving device, wherein a sampling frequency for sampling the audio signal by the receiving device is 48 KHz, a channel number used by the receiving device is a single channel, and a quantization used by the receiving device is an 8-bit quantization; and demodulating the sampled audio signal for obtaining the digital signal by the receiving device, wherein a modulating frequency of a binary bit “0” in the digital signal is set as 12 KHz, a modulating frequency of a binary bit “1” in the digital signal is set as 16 KHz, and a modulating width is set to have 1000 sampling points in the 2FSK modulation scheme, wherein the step of demodulating the sampled audio signal for obtaining the digital signal by the receiving device comprises: transforming the sampled audio signal from a time domain signal to a frequency domain signal; analyzing the sampled audio signal in the frequency domain by using 64 points as an analyzing period; outputting “0” as an output result if a frequency of one point having a maximum power is closest to 12 KHz; outputting “1” as an output result if a frequency of one point having a maximum power is closest to 16 KHz; performing a statistical analysis on the output results by using a window with a length of 16 bits; demodulating the digital signal as “1” if “1” in the output results within the windows occurs more; demodulating the digital signal as “0” if “0” in the output results within the windows occurs more; and shifting the window for continuing to performing the statistical analysis on the output results until obtaining the entire digital signal.