In some example embodiments, there is provided a tag. The tag may include an antenna configured to receive a first radio frequency signal and to reradiate a second radio frequency signal; and an ultrasonic transducer coupled to the antenna, wherein an ultrasound signal received by the ultrasonic transducer causes a variation of at least one property of the ultrasonic transducer, wherein the variation of the at least one property imparts a modulation onto at least a portion of the first radio frequency signal, and wherein the modulated first radio frequency signal is reradiated by the antenna as the second radio frequency signal. Related system, methods, and articles of manufacture are also disclosed.

A portable data processing device for forming a wireless network includes a chamber configured within a housing; a microprocessor; a power supply; a sensor communicatively coupled to the microprocessor; and data storage media; and a wireless communication module. The microprocessor is configured to broadcast, by the wireless communication module, a device identification signal; listen for an external device identification signal; transmit device capability data; receive external device capability data. The microprocessor is further configured to receive an internal measurement from the sensor; transmit the internal measurement; receive an external measurement from the external device; analyze the internal measurement and the external measurement to determine an analysis result; and transmit the analysis result.

A method for limiting voltage at an input of an integrated circuit of a transponder contactlessly communicating with a reader includes, during the contactless communication: receiving a carrier signal at an antenna of the transponder; and controlling gate voltages of two transistors of a rectifier circuit of the transponder so as to modify an input impedance of the integrated circuit, wherein the two transistors are cross-coupled between terminals of the antenna and a reference voltage.

A method for recognizing a user carrying a terminal capable of receiving a radio signal coming from a device equipped with an antenna suitable for transmitting the signal. The signal is intended to be transmitted between the device and the terminal by using electromagnetic wave conduction capacities of the body of the user when at least one part of his/her body is in the vicinity of the antenna. When the user makes a characteristic movement, to move the part of his/her body close to the antenna, the device transmits a characteristic signal of the movement. The method includes: receiving a signal coming from the device; generating a characteristic datum of the movement; obtaining at least one signature; comparing the characteristic datum with the signature; and depending on the results of the comparison, recognizing the user.

A near field communication NFC communication method and apparatus, and an electronic device are provided. The method includes: receiving a first signal sent by an NFC card reader; and in response to the first signal, performing data interaction with the NFC card reader using target contactless information in a case that a first NFC emulation card is in an active state; where the first NFC emulation card is a non-access-control-type NFC emulation card, and the target contactless information carries a target identification code corresponding to an access-control-type target NFC emulation card.

In accordance with a first aspect of the present disclosure, a channel equalizer is provided for use in a near field communication (NFC) device, the channel equalizer comprising: a filter configured to receive an input signal and to generate a filtered output signal; an estimator configured to determine filter coefficients to be used by said filter; a synchronizer configured to determine when to enable the channel equalizer and to provide one or more corresponding control signals to the estimator. In accordance with a second aspect of the present disclosure, a corresponding method of operating a channel equalizer for use in a near field communication (NFC) device is conceived.

In an embodiment, a method of managing an output power delivered by an antenna of a NFC apparatus includes: providing a matching circuit with a first tuning capacitive network coupled in series between a NFC controller and the antenna and with a second tuning capacitive network coupled to the NFC controller and the antenna and to a reference terminal, wherein the first or second tuning capacitive network has a variable capacitive value; determining tuning capacitive values of the first tuning capacitive networks to adjust a delivered output power at a desired level; and setting the tuning capacitive values of the first tuning capacitive network to the tuning capacitive values.

Example embodiments of systems and methods for data transmission system between transmitting and receiving devices are provided. In an embodiment, each of the transmitting and receiving devices can contain a master key. The transmitting device can generate a diversified key using the master key, protect a counter value and encrypt data prior to transmitting to the receiving device, which can generate the diversified key based on the master key and can decrypt the data and validate the protected counter value using the diversified key.

Example embodiments of systems and methods for data transmission system between transmitting and receiving devices are provided. In an embodiment, each of the transmitting and receiving devices can contain a master key. The transmitting device can generate a diversified key using the master key, protect a counter value and encrypt data prior to transmitting to the receiving device, which can generate the diversified key based on the master key and can decrypt the data and validate the protected counter value using the diversified key.

One example discloses a wireless device, including: a first near-field device, including a near-field transmitter or receiver and a controller, configured to be coupled to a first conductive surface; wherein the near-field receiver includes a set of tuning values configured to either set a near-field resonance frequency or an operational bandwidth of the first near-field device; wherein the controller is configured to change at least one of the tuning values in response to a change in a distance between the first surface and a second conductive surface; and wherein the controller is configured to calculate the distance, between the first conductive surface and the second conductive surface, based on the at least one of the tuning values.