MODULATION CONTROL THROUGH ADAPTIVE PHASE ADJUSTMENT

• US 20180040953A1
• Filed: 08/03/2016
• Published: 02/08/2018
• Est. Priority Date: 08/03/2016
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Gebhart, Michael, Nunziata, Fred George, Watzinger, Hubert
• Granted Patent: US 9,997,829 B2
• Time in Patent Office: Days
• CPC Class Codes: H01Q 1/2291 used in bluetooth or WI-FI devices of Wireless Local Area Networks [WLAN] H01Q1/241 takes precedence; WLAN in general H04W
• CPC Class Codes: H01Q 3/30 varying the relative phase between the radiating elements of an array H01Q3/2605, H01Q3/2658, H01Q3/2682, H01Q3/44 take precedence
• CPC Class Codes: H04B 5/72 for local intradevice communication
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

A Near Field Communication (NFC) enabled device is disclosed. The NFC device includes an antenna. The NFC device also includes an impedance matching network, a carrier frequency generator to generate a carrier wave, a receiver for receiving a magnetic induction wave, a transmitter, a driver circuit configured to alter an impedance of an antenna network associated with the antenna between a first impedance and a second impedance and a control unit. The control unit is configured to derive a first phase difference between the received magnetic induction wave and an internal clock at the first impedance and a second phase difference between the received magnetic induction wave and the internal clock at the second impedance. The control unit is further configured to change a phase of the carrier wave based on a difference between the first phase difference and a second phase difference.

Claims

1. A Near Field Communication (NFC) enabled device, comprising:

an antenna;

an impedance matching network;

a carrier frequency generator to generate a carrier wave;

a receiver for receiving a magnetic induction wave;

a driver circuit configured to alter an impedance of an antenna network associated with the antenna between a first impedance and a second impedance;

a transmitter; and

a control unit configured to derive a first phase difference between the received magnetic induction wave and an internal clock at the first impedance and a second phase difference between the received magnetic induction wave and the internal clock at the second impedance, wherein the control unit is further configured to change a phase of the carrier wave based on a difference between the first phase difference and a second phase difference.

2. The NFC enabled device of claim 1, wherein the control unit is further configured to multiple the difference between the first phase difference and a second phase difference by a preselected factor.

3. The NFC enabled device of claim 1, wherein the control unit is further configured to change the phase of the carrier wave based on a preselected offset in addition to the difference between the first phase difference and a second phase difference.

4. The NFC enabled device of claim 1, further including a lookup table to derive a value of a phase change based on the difference between the first phase difference and a second phase difference.

5. The NFC enabled device of claim 1, the control unit is further configured to derive a value of a phase change based on the difference between the first phase difference and a second phase difference using a preset formula that represents a graph between a phase adjustment value and the difference between the first phase difference and a second phase difference.

6. The NFC enabled device of claim 1, wherein the control unit is configured to calculate the difference between the first phase difference and a second phase difference immediately prior to transmitting each frame through active load modulation.

7. The NFC enabled device of claim 6, wherein the control unit is configured to change the phase of the carrier wave based on the difference between the first phase difference and a second phase difference immediately prior to transmitting each frame through active load modulation.

8. A method of correcting a phase of a carrier wave in a NFC enabled device, the method comprising:

changing an impedance of an antenna network associated with an antenna of the NFC enabled device to a first selected impedance;

determining a first phase difference between a magnetic induction wave and an internal clock at the first impedance;

changing the impedance of the antenna network associated with the antenna of the NFC enabled device to a second selected impedance;

determining a second phase difference between the received magnetic induction wave and the internal clock at the second impedance; and

changing a phase of a carrier wave generated using the internal clock, based on a difference between the first phase difference and a second phase difference.

9. The method of claim 8, wherein the changing the phase includes multiplying the difference between the first phase difference and a second phase difference by a preselected factor associated with the NFC enabled device.

10. The method of claim 8, wherein the changing the phase further include altering the phase of the carrier wave based on a preselected offset in addition to the difference between the first phase difference and a second phase difference.

11. The method of claim 8, further including searching a data table to derive a value of a phase change based on the difference between the first phase difference and a second phase difference.

12. The method of claim 8, further includes deriving a value of a phase change based on the difference between the first phase difference and a second phase difference using a preset formula that represents a graph between a phase adjustment value and the difference between the first phase difference and a second phase difference.

13. The method of claim 8, wherein the changing the phase is performed immediately prior to transmitting each frame through active load modulation.

14. A computer readable media including programming instructions which when executed by a processor perform an operation of adjusting a phase of a carrier wave in a NFC enabled device, the operation includes:

changing an impedance of an antenna network associated with an antenna of the NFC enabled device to a first selected impedance;

determining a first phase difference between a magnetic induction wave and an internal clock at the first impedance;

changing the impedance of the antenna network associated with the antenna of the NFC enabled device to a second selected impedance;

determining a second phase difference between the received magnetic induction wave and the internal clock at the second impedance; and

changing a phase of a carrier wave generated using the internal clock, based on a difference between the first phase difference and a second phase difference.

15. The computer readable media of claim 14, wherein the changing includes multiplying the difference between the first phase difference and a second phase difference by a preselected factor associated with the NFC enabled device.

16. The computer readable media of claim 14, wherein the changing further include altering the phase of the carrier wave based on a preselected offset in addition to the difference between the first phase difference and a second phase difference.

17. The computer readable media of claim 14, further including searching a data table to derive a value of a phase change based on the difference between the first phase difference and a second phase difference.

18. The computer readable media of claim 14, further includes deriving a value of a phase change based on the difference between the first phase difference and a second phase difference using a preset formula that represents a graph between a phase adjustment value and the difference between the first phase difference and a second phase difference.

19. The computer readable media of claim 14, wherein the changing is performed immediately prior to transmitting each frame through active load modulation.