NFC device and method of operating the same
In accordance with a first aspect of the present disclosure, a near field communication (NFC) device is provided, comprising: a modulator configured to modulate a carrier signal received from an external reader, resulting in a modulated carrier signal; a controller configured to control a transmission of the modulated carrier signal to the external reader; a transmitter driver configured to transmit said modulated carrier signal, said transmitter driver having a variable resistance; wherein the controller is further configured to change said variable resistance during a modulation phase of the NFC device such that a clock synchronization window is widened. In accordance with a second aspect of the present disclosure, a corresponding method of operating an NFC device is conceived. In accordance with a third aspect of the present disclosure, a non-transitory machine-readable medium is provided, comprising instructions which, when executed, carry out a method of the kind set forth.
1. A near field communication, NFC, device, comprising:
a modulator configured to modulate a carrier signal received from an external reader, resulting in a modulated carrier signal;
a controller configured to control a transmission of the modulated carrier signal to the external reader; and
a transmitter driver configured to transmit said modulated carrier signal, said transmitter driver having a variable resistance;
wherein the controller is further configured to change said variable resistance during a modulation phase of the NFC device such that a clock synchronization window is widened;
wherein the controller is configured to change said variable resistance by selecting a resistance from a plurality of different resistances; and
wherein the controller is configured to select different resistances for consecutive transmission pulses during the modulation phase.
2. The NFC device of claim 1 , wherein the controller is further configured to select different resistances during the non-modulation phase.
3. The NFC device of claim 1 , wherein the controller is further configured to remove one or more transmission pulses at a beginning of one or more modulation phases of the NFC device.
4. The NFC device of claim 1 , further comprising a receiver for receiving the carrier signal, wherein the controller is further configured to control a reception of the carrier signal and to change, during the modulation phase of the NFC device, a variable resistance of an HF attenuator comprised in said receiver.
5. The NFC device of claim 4 , wherein the controller is configured to change said variable resistance of the HF attenuator by selecting a resistance from a plurality of different resistances.
6. The NFC device of claim 5 , wherein the controller is configured to select different resistances for consecutive transmission pulses during the modulation phase.
7. The NFC device of claim 6 , wherein the controller is further configured to select different resistances during the non-modulation phase.
8. A mobile device comprising the NFC device of claim 1 .
9. A method of operating a near field communication, NFC, device, the method comprising:
modulating, by a modulator, a carrier signal received from an external reader, resulting in a modulated carrier signal;
controlling, using a controller, a transmission of the modulated carrier signal to the external reader; and
transmitting, by a transmitter driver, said modulated carrier signal, said transmitter driver having a variable resistance;
wherein the controller changes said variable resistance during a modulation phase of the NFC device such that a clock synchronization window is widened;
wherein the controller changes said variable resistance by selecting a resistance from a plurality of different resistances; and
wherein the controller changes said variable resistance by selecting a resistance from a plurality of different resistances.
10. The method of claim 9 , wherein the controller selects different resistances during the non-modulation phase.
11. The method of claim 9 , wherein the controller removes one or more transmission pulses at a beginning of one or more modulation phases of the NFC device.
12. The method of claim 9 , wherein the controller further controls a reception of the carrier signal by a receiver and changes, during the modulation phase of the NFC device, a variable resistance of an HF attenuator comprised in said receiver.
13. The method of claim 12 , wherein the controller changes said variable resistance of the HF attenuator by selecting a resistance from a plurality of different resistances.
14. The method of claim 13 , wherein the controller selects different resistances for consecutive transmission pulses during the modulation phase.
15. The method of claim 14 , wherein the controller selects different resistances during the non-modulation phase.
16. The method of claim 9 , wherein the method is implemented as instructions stored on a non-transitory machine-readable medium.