NFC device and method of operating the same
There is described a method of operating an NFC device, the method comprising: determining a resonance frequency of a matching network of the NFC device; 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 at least one configurable setting that influences a damping behavior of the transmitted modulated carrier signal, wherein, during a modulation phase of the NFC device, the controller selects and applies the at least one configurable setting based on the determined resonance frequency such that a clock synchronization window is widened. Furthermore, a corresponding NFC device is described.
1 . A method of operating an NFC device, the method comprising:
determining a resonance frequency of a matching network of the NFC device,
wherein determining the resonance frequency includes:
sweeping a transmitter clock frequency over a predetermined frequency range,
identifying a frequency value within the predetermined frequency range at which a voltage at a receiver circuit of the NFC device has a minimum value or a maximum value, and
using the identified frequency value as the resonance frequency;
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 at least one configurable setting that influences a damping behavior of the transmitted modulated carrier signal,
wherein, during a modulation phase of the NFC device, the controller selects and applies the at least one configurable setting based on the determined resonance frequency such that a clock synchronization window is widened.
2 . The method according to claim 1 , wherein the at least one configurable setting is associated with a variable resistance of the transmitter driver.
3 . The method according to claim 1 , wherein the at least one configurable setting comprises a sequence of different resistances to be applied during different parts of the modulation phase of the NFC device.
4 . The method according to claim 1 , wherein the at least one configurable setting comprises a phase of the transmitted modulated carrier signal.
5 . The method according to claim 1 , wherein the at least one configurable setting comprises a TX shaping functionality to be applied during the modulation phase of the NFC device.
6 . The method according to claim 5 , wherein the TX shaping functionality is selected from a group consisting of no TX shaping and at least one predetermined TX shaping method.
7 . The method according to claim 1 , wherein the controller selects the at least one configurable setting from a plurality of predetermined settings, each of the predetermined settings corresponding to a particular resonance frequency value.
8 . The method according to claim 7 , wherein the controller selects the at least one configurable setting by applying interpolation to at least two predetermined settings of the plurality of predetermined settings.
9 . The method according to claim 1 , wherein the determining is performed with the NFC device having an unloaded antenna.
10 . The method according to claim 1 , wherein the determining is performed with the NFC device having a loaded antenna.
11 . An NFC device, the device comprising:
a resonance frequency determining circuitry configured to sweep a transmitter clock frequency over a predetermined frequency range, identify a frequency value within the predetermined frequency range at which a voltage at a receiver circuit of the NFC device has a minimum value or a maximum value, and use the identified frequency value as a resonance frequency of a matching network of the NFC device;
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 at least one configurable setting that influences a damping behavior of the transmitted modulated carrier signal,
wherein the controller is further configured to select and apply the at least one configurable setting based on the determined resonance frequency such that a clock synchronization window is widened.
12 . The device according to claim 11 , wherein the at least one configurable setting is associated with a variable resistance of the transmitter driver.
13 . The device according to claim 11 , wherein the at least one configurable setting comprises a sequence of different resistances to be applied during different parts of the modulation phase of the NFC device.
14 . The device according to claim 11 , wherein the at least one configurable setting comprises a phase of the transmitted modulated carrier signal.
15 . The device according to claim 11 , wherein the at least one configurable setting comprises a TX shaping functionality to be applied during the modulation phase of the NFC device.
16 . The device according to claim 15 , wherein the TX shaping functionality is selected from a group consisting of no TX shaping and at least one predetermined TX shaping method.
17 . He device according to claim 11 , wherein the controller selects the at least one configurable setting from a plurality of predetermined settings, each of the predetermined settings corresponding to a particular resonance frequency value.
18 . The device according to claim 17 , wherein the controller selects the at least one configurable setting by applying interpolation to at least two predetermined settings of the plurality of predetermined settings.
19 . The device according to claim 11 , wherein the resonance frequency determining circuitry is configured to determine the resonance frequency with the NFC device having an unloaded antenna.
20 . The device according to claim 11 , wherein the resonance frequency determining circuitry is configured to determine the resonance frequency with the NFC device having a loaded antenna.