Signal enhancement for load modulation

1. A method of enhancing a signal for load modulation from reading a smartcard, the method comprising:

generating, by transceiver circuitry, an antenna signal;

transmitting an antenna signal field associated with the antenna signal;

generating a reference signal that is substantially constant in amplitude and phase, and substantially in phase with a carrier frequency of the antenna signal;

receiving a modulated antenna signal, wherein the modulated antenna signal comprises the antenna signal that has been modulated as a result of the presence of a smartcard within the antenna signal field;

subtracting the reference signal from the modulated antenna signal to produce a resultant signal; and

providing the resultant signal to receiving circuitry of the transceiver circuitry.

2. The method of enhancing a signal for load modulation from reading a smartcard according to claim 1 , wherein the reference signal and the antenna signal are generated simultaneously.

3. The method of enhancing a signal for load modulation from reading a smartcard according to claim 1 , wherein subtracting the reference signal from the modulated antenna signal is done using a transformer.

4. The method of enhancing a signal for load modulation from reading a smartcard according to claim 1 , further comprising actively adjusting a phase of the reference signal based on a phase change of the modulated antenna signal resulting from modulation from the smartcard.

5. The method of enhancing a signal for load modulation from reading a smartcard according to claim 1 , further comprising reducing an amplitude of the resultant signal.

6. The method of enhancing a signal for load modulation from reading a smartcard according to claim 1 , further comprising adjusting a phase of the reference signal relative to the antenna signal between about 30° and 60°.

7. The method of enhancing a signal for load modulation from reading a smartcard according to claim 1 , wherein subtracting the reference signal from the modulated antenna signal is done using one or more of resistive elements, capacitive elements, or a differential amplifier.

8. The method of enhancing a signal for load modulation from reading a smartcard according to claim 1 , wherein transmitting the antenna signal field is done by a first antenna and receiving the modulated antenna signal is done by a second antenna.

9. A smartcard reader for enhancing a load modulated signal, the smartcard reader comprising transceiver circuitry configured to:

generate an antenna signal;

transmit an antenna signal field associated with the antenna signal;

generate a reference signal that is substantially constant in amplitude and phase and that is substantially in phase with a carrier frequency of the antenna signal;

receive a modulated antenna signal, wherein the modulated antenna signal comprises the antenna signal that has been modulated due to the presence of a smartcard within the antenna signal field;

subtract the reference signal from the modulated antenna signal to produce a resultant signal; and

provide the resultant signal to receiving circuitry of the transceiver circuitry.

10. The smartcard reader for enhancing a load modulated signal according to claim 9 , wherein the transceiver circuitry is further configured to reduce an amplitude of the resultant signal.

11. The smartcard reader for enhancing a load modulated signal according to claim 9 , wherein the transceiver circuitry comprises a transformer that subtracts the reference signal from the modulated antenna signal.

12. The smartcard reader for enhancing a load modulated signal according to claim 9 , wherein the transceiver circuitry comprises a first antenna that generates the antenna signal and a second antenna that receives the modulated antenna signal.

13. The smartcard reader for enhancing a load modulated signal according to claim 9 , wherein the transceiver circuitry is further configured to adjust a phase of the reference signal.

14. The smartcard reader for enhancing a load modulated signal according to claim 9 , wherein the transceiver circuitry is further configured to actively adjust a phase and amplitude of the reference signal based on a phase change of the modulated antenna signal resulting from modulation from the smartcard.

15. A transceiver for a smartcard reader for enhancing a load modulated signal, the transceiver comprising:

resonating circuitry comprising inductive and capacitive elements configured to generate a reference signal and an antenna signal, wherein the reference signal is substantially constant in amplitude and phase, and wherein the reference signal is substantially in phase with a carrier frequency of the antenna signal;

antenna circuitry comprising at least one antenna coupled to the resonating circuitry configured to:

transmit an antenna field associated with the antenna signal and

receive a modulated antenna signal, wherein the modulated antenna signal comprises the antenna signal that has been modulated due to the presence of a smartcard within the antenna signal field; and

differential circuitry that is coupled with the antenna circuitry and is configured to subtract the reference signal from the modulated antenna signal to produce a resultant signal.

16. The transceiver for a smartcard reader for enhancing a load modulated signal according to claim 15 , wherein the at least one antenna comprises a first antenna that transmits the antenna field and a second antenna that receives the modulated antenna signal.

17. The transceiver for a smartcard reader for enhancing a load modulated signal according to claim 15 , wherein the differential circuitry comprises one or more of a transformer, a resistive element, or a differential amplifier.

18. The transceiver for a smartcard reader for enhancing a load modulated signal according to claim 15 , further comprising a transformer configured to reduce an amplitude of the resultant signal.

19. The transceiver for a smartcard reader for enhancing a load modulated signal according to claim 15 , further comprising one or more of an inductive element or a capacitive element to adjust a phase of the reference signal.

20. The smartcard reader for enhancing a load modulated signal according to claim 15 , further comprising a phase-lock loop to actively adjust a phase of the reference signal based on a phase change of the modulated antenna signal resulting from modulation from the smartcard.