Abstract: An embodiment device comprises a phase locked loop and a frequency locked loop having in common the same controlled oscillator. The device is firstly placed in the card emulation mode at the beginning of a communication between the contactless communication device and a contactless reader, the firstly placing comprising synchronizing within the contactless device, an ALM carrier frequency with a reader carrier frequency by operating at least the phase locked loop, and upon reception by the contactless communication device of an indication sent by the reader indicating a further communication in a peer to peer mode with the reader, the device is secondly placed in the peer to peer mode, the secondly placing including deactivating the phase locked loop and operating the frequency locked loop with a reference clock signal and a frequency set point depending on the reader carrier frequency and the frequency of the reference clock signal.

Abstract: A near-field communication circuit of a first NFC device alternates, in low power mode, between: first phases of emission of field bursts and second phases spanning an entire duration separating two successive first phases. Each second phase includes a field detector enabling phase. In one implementation, the field detector enabling phase extends all along a duration of the second phase. In an alternate implementation, the field detector enabling phase is interrupted by field detector disabling phases. Each field detector disabling phase has a duration shorter than a minimum duration of each first phase.

Abstract: In an embodiment a method for dynamic power control of a power level transmitted by an antenna of a contactless reader is disclosed. The method may include supplying a power to the antenna and performing at least one power adjusting cycle for adjusting a power level during a contactless transaction with a transponder, each power adjusting cycle including modifying the power supplied to the antenna to a predetermined level of power, performing a first measuring of a loading effect on the antenna at the predetermined level of power and adjusting the power level according to the measured loading effect.

Abstract: A method for controlling a signal envelope shape of modulation pulses in a driver of a wireless transmitter includes supplying a first voltage to the driver during a non-modulated state, supplying a second voltage configurable by a configurable modulation index value to the driver during a modulated state, switching between the non-modulated state and the modulated state comprising setting the modulation index value to configure the second voltage level at the same level as the first voltage and then switching between supplying the first voltage to the driver and supplying the second voltage to the driver, and filtering to a limited bandwidth the variations of the second voltage resulting from configuring the modulation index value.

Abstract: An embodiment device comprises a phase locked loop and a frequency locked loop having in common the same controlled oscillator. The device is firstly placed in the card emulation mode at the beginning of a communication between the contactless communication device and a contactless reader, the firstly placing comprising synchronizing within the contactless device, an ALM carrier frequency with a reader carrier frequency by operating at least the phase locked loop, and upon reception by the contactless communication device of an indication sent by the reader indicating a further communication in a peer to peer mode with the reader, the device is secondly placed in the peer to peer mode, the secondly placing including deactivating the phase locked loop and operating the frequency locked loop with a reference clock signal and a frequency set point depending on the reader carrier frequency and the frequency of the reference clock signal.

Abstract: In an embodiment a method for dynamic power control of a power level transmitted by an antenna of a contactless reader is disclosed. The method may include supplying a power to the antenna and performing at least one power adjusting cycle for adjusting a power level during a contactless transaction with a transponder, each power adjusting cycle including modifying the power supplied to the antenna to a predetermined level of power, performing a first measuring of a loading effect on the antenna at the predetermined level of power and adjusting the power level according to the measured loading effect.

Abstract: A near field communication (NFC) method includes activating an NFC device second device in response to a first electromagnetic field generated by a nearby NFC device. The NFC device generates a second electromagnetic field after being activated. The first NFC device can detect the second electromagnetic field and initiate a near field communication process.

Abstract: An RFID transponder includes a coding and modulation unit that generates a transmission signal by modulating an oscillator signal with an encoded bit signal. During a first and a second time segment, the encoded bit signal assumes a first and a second logic level, respectively. The transmission signal includes a first signal pulse having a first phase within the first time segment and a second signal pulse having a second phase that is shifted with respect to the first phase by a predefined phase difference within the second time segment. The transmission signal is paused for a pause period between the first and the second signal pulse. The pause period is shorter than a mean value of a period of the first time segment and a period of the second time segment.

Abstract: A method for controlling a signal envelope shape of modulation pulses in a driver of a wireless transmitter includes supplying a first voltage to the driver during a non-modulated state, supplying a second voltage configurable by a configurable modulation index value to the driver during a modulated state, switching between the non-modulated state and the modulated state comprising setting the modulation index value to configure the second voltage level at the same level as the first voltage and then switching between supplying the first voltage to the driver and supplying the second voltage to the driver, and filtering to a limited bandwidth the variations of the second voltage resulting from configuring the modulation index value.

Abstract: An RFID transponder includes a coding and modulation unit that generates a transmission signal by modulating an oscillator signal with an encoded bit signal. During a first and a second time segment, the encoded bit signal assumes a first and a second logic level, respectively. The transmission signal includes a first signal pulse having a first phase within the first time segment and a second signal pulse having a second phase that is shifted with respect to the first phase by a predefined phase difference within the second time segment. The transmission signal is paused for a pause period between the first and the second signal pulse. The pause period is shorter than a mean value of a period of the first time segment and a period of the second time segment.

Abstract: A demodulator circuit receives an envelope signal for comparison against a switched reference signal that is generated as a function of the envelope signal and as a function of an output signal of the demodulator circuit. The switched reference signal is filtered by an RC filter prior to comparison. The output signal is dependent on a difference between the filtered switched reference signal and the envelope signal.

Abstract: An RFID transponder includes a coding and modulation unit that generates a transmission signal by modulating an oscillator signal with an encoded bit signal. During a first and a second time segment, the encoded bit signal assumes a first and a second logic level, respectively. The transmission signal includes a first signal pulse having a first phase within the first time segment and a second signal pulse having a second phase that is shifted with respect to the first phase by a predefined phase difference within the second time segment. The transmission signal is paused for a pause period between the first and the second signal pulse. The pause period is shorter than a mean value of a period of the first time segment and a period of the second time segment.

Abstract: A method of wireless communication includes transmitting frames from a transponder to a reader and synchronizing between a reader carrier frequency and an active load modulation (ALM) carrier frequency within each transmitted frame. Each transmitted frame includes ALM carrier bursts generated from subcarrier modulation by binary phase shift keying (BPSK) data encoding and producing signal oscillations at a transponder antenna after each ALM carrier burst generation, The synchronizing occurs at each phase change of the data encoding when no burst is generated during a half period of the subcarrier preceding the phase change and a half period of the subcarrier following this phase change. The transponder antenna has a moderate quality factor sufficient to naturally damp the signal oscillations so that the synchronizing is performed without performing any controlled signal oscillations damping.

Abstract: When communicating using active load modulation in a Radio Frequency Identification (RFID) system, a carrier signal having a carrier frequency is received from a reader device. In response, a modulated signal is generated and a burst of a sending signal is transmitted. The sending signal is decayed at the end of the burst.

Abstract: An RFID transponder includes a coding and modulation unit that generates a transmission signal by modulating an oscillator signal with an encoded bit signal. During a first and a second time segment, the encoded bit signal assumes a first and a second logic level, respectively. The transmission signal includes a first signal pulse having a first phase within the first time segment and a second signal pulse having a second phase that is shifted with respect to the first phase by a predefined phase difference within the second time segment. The transmission signal is paused for a pause period between the first and the second signal pulse. The pause period is shorter than a mean value of a period of the first time segment and a period of the second time segment.

Abstract: An RFID transponder includes a coding and modulation unit that generates a transmission signal by modulating an oscillator signal with an encoded bit signal. During a first and a second time segment, the encoded bit signal assumes a first and a second logic level, respectively. The transmission signal includes a first signal pulse having a first phase within the first time segment and a second signal pulse having a second phase that is shifted with respect to the first phase by a predefined phase difference within the second time segment. The transmission signal is paused for a pause period between the first and the second signal pulse. The pause period is shorter than a mean value of a period of the first time segment and a period of the second time segment.

Abstract: An RFID transponder device has antenna terminals for coupling an antenna system to the device. A transmitter and a receiver are coupled to the antenna terminals. The device has at least one damping resistance connected to at least one of the antenna terminals. The at least one damping resistance is connected, depending on a voltage swing at the antenna terminals during a transmission burst period, either together with a serially connected switch in parallel to the antenna terminals that are coupled to the receiver, or together with a parallel connected switch between one of the antenna terminals and a terminal of the transmitter. A damping control is configured to activate the at least one damping resistance during a damping period after the transmission burst period by controlling the respective switch.

Abstract: In an embodiment, a carrier signal generation circuit can be used for a Radio-frequency identification (RFID) transponder device. A frequency divider circuit has a first input to receive a first frequency signal, a second input to receive a division ratio signal, and an output to provide a carrier signal as a function of the first frequency signal and the division ratio signal. A phase difference circuit has a first input to receive an analog reader device carrier signal, a second input to receive a signal based on the first frequency signal and an output to provide a digital phase difference signal as a function of the reader device carrier signal and the signal based on the first frequency signal. A signal processor has an input coupled to the output of the phase difference circuit.

Abstract: A method of wireless communication includes transmitting frames from a transponder to a reader and synchronizing between a reader carrier frequency and an active load modulation (ALM) carrier frequency within each transmitted frame. Each transmitted frame includes ALM carrier bursts generated from subcarrier modulation by binary phase shift keying (BPSK) data encoding and producing signal oscillations at a transponder antenna after each ALM carrier burst generation, The synchronizing occurs at each phase change of the data encoding when no burst is generated during a half period of the subcarrier preceding the phase change and a half period of the subcarrier following this phase change. The transponder antenna has a moderate quality factor sufficient to naturally damp the signal oscillations so that the synchronizing is performed without performing any controlled signal oscillations damping.

Abstract: A circuit includes an antenna circuit including a number of capacitors and an inductor. The antenna circuit is configured to transmit an output signal upon receiving an input transmit signal. A first control block is configured to transmit an enabling signal upon detecting a presence of a supply voltage at a feeding terminal of the actively transmitting tag in response to the actively transmitting tag being inserted into a host device. A VCO is configured to generate the input transmit signal with the frequency of the interrogator carrier signal upon receiving the enabling signal from the first control block and upon receiving the control voltage from the memory. A second control block is configured to enable a subset of the plurality of capacitors of the antenna circuit upon receiving the enabling signal from the first control block.