US 12,457,014 B2
System and method for distinguishing between active and passive NFC devices based on adjustment of carrier frequency
Tianhao Xiong, Shanghai (CN); and Gang Wu, Shanghai (CN)
Assigned to STMICROELECTRONICS (CHINA) INVESTMENT CO., LTD., Shanghai (CN)
Appl. No. 18/257,268
Filed by STMICROELECTRONICS (CHINA) INVESTMENT CO., LTD., Shanghai (CN)
PCT Filed Dec. 22, 2020, PCT No. PCT/CN2020/138274
§ 371(c)(1), (2) Date Jun. 13, 2023,
PCT Pub. No. WO2022/133717, PCT Pub. Date Jun. 30, 2022.
Prior Publication US 2024/0048183 A1, Feb. 8, 2024
Int. Cl. H04B 5/79 (2024.01); H04B 5/26 (2024.01); H04B 5/45 (2024.01); H04B 5/77 (2024.01)
CPC H04B 5/79 (2024.01) [H04B 5/26 (2024.01); H04B 5/45 (2024.01); H04B 5/77 (2024.01)] 20 Claims
OG exemplary drawing
 
1. A method comprising:
transmitting a carrier signal from a near field communication reader;
transmitting an interrogation signal with the carrier signal;
receiving an initial portion of a response signal from a near field communication device responsive to the interrogation signal;
adjusting a frequency of the carrier signal after receiving the initial portion of the response signal and prior to receiving an entirety of the response signal;
receiving a remainder of the response signal; and
determining whether the near field communication device is a passive load modulation near field communication device or an active load modulation near field communication device based on the remainder of the response signal.