System and method to test and calibrate card-detection using active tag emulation
This specification discloses methods and devices for emulating a tag device that communicates via inductive coupling, such as a NFC (Near Field Communication) tag device. In some embodiments, this specification discloses methods and devices to use this tag device “emulation” for testing, validating, calibrating, and characterizing a reader device. In some embodiments, a tag emulation device can emulate movement of the tag emulation device relative to the reader device by changing configuration parameters of the tag emulation device and by not actually moving the tag emulation device relative to the reader device. In some embodiments, these configuration parameters changes include: changing a Tx (transmitter) voltage, changing a Tx driver impedance, changing a HF (high frequency) attenuator resistance, changing a Tx output modulation, changing a matching network tuning, changing a phase of a Tx signal versus a carrier signal from the reader device, enabling one or two Tx drivers.
1. A method for emulating a tag device that communicates via inductive coupling, the method comprising:
generating, by a transmitter unit of a reader device that communicates via inductive coupling, a transmitted field;
receiving, by a tag emulation device, the transmitted field,
wherein the tag emulation device emulates coupling change of the tag emulation device relative to the reader device by changing configuration parameters of the tag emulation device and by not moving the tag emulation device relative to the reader device, wherein changing configuration parameters includes changing a phase of a transmitted signal from the tag emulation device versus a phase of a carrier signal of the transmitted field from the reader device;
detecting, by the reader device, an impedance change of an antenna and matching network system of the reader device,
wherein the impedance change corresponds to the emulated coupling change of the tag emulation device relative to the reader device.
2. The method of claim 1 , wherein the coupling change corresponds to movement of the tag emulation device relative to the reader device.
3. The method of claim 1 , wherein the coupling change corresponds to changing one of the following:
a position of the tag emulation device relative to the reader device,
an orientation of the tag emulation device relative to the reader device,
an antenna size of the tag emulation device and/or an antenna size of the reader device.
4. The method of claim 3 , wherein changing the position comprises one or more of the following:
changing a distance of the tag emulation device relative to the reader device,
changing an offset position of the tag emulation device relative to the reader device while keeping the distance fixed.
5. The method of claim 1 further comprising:
using the tag emulation device for one or more of the following:
testing the reader device,
validating the reader device,
calibrating the reader device,
characterizing the reader device.
6. The method of claim 1 , wherein the reader device is further comprised of a receiver unit, wherein the impedance change is detected by monitoring a voltage of the receiver unit.
7. The method of claim 1 , wherein the reader device is further comprised of a receiver unit, wherein the impedance change is detected by monitoring a signal of the receiver unit, wherein the signal is comprised of one or more of the following:
a voltage,
a current,
a power.
8. The method of claim 1 , wherein the impedance change is detected by monitoring a signal of the transmitter unit, wherein the signal is comprised of one or more of the following:
a current,
a voltage,
a power.
9. The method of claim 1 , wherein the reader device is further comprised of a receiver unit, wherein the impedance change is detected by monitoring a phase difference between a signal transmitted by the transmitter unit of the reader device and a signal received by the receiver unit of the reader device.
10. The method of claim 1 , wherein the tag emulation device is comprised of:
a transmitter (Tx) unit, wherein the transmitter (Tx) unit is comprised of at least one Tx driver,
a receiver (Rx) unit, wherein the receiver (Rx) unit is comprised of a HF (high frequency) attenuator,
a matching network.
11. The method of claim 10 , wherein the tag emulation device emulates coupling change of the tag emulation device relative to the reader device by changing one or more the following configuration parameters of the tag emulation device:
changing a Tx voltage,
changing a Tx driver impedance,
changing a HF attenuator resistance,
changing a Tx output modulation,
changing a matching network tuning,
enabling one or two Tx drivers.
12. The method of claim 1 , wherein the tag emulation device is a NFC-enabled device in card mode, wherein NFC stands for Near Field Communication, wherein the tag emulation device is a NFC-enabled device in one of the following modes:
ALM (active load modulation) card mode,
PLM (passive load modulation) card mode.
13. The method of claim 5 , wherein testing of the reader device is conducted using one of the following testing techniques:
over-the-air (OTA) testing,
conducted testing.
14. A computer program product comprising executable instructions encoded in a non-transitory computer readable medium which, when executed by the tag emulation device, carry out or control the method of claim 1 .
15. A tag emulation device that communicates via inductive coupling, the tag emulation device comprising:
a receiver (Rx) unit, the receiver (Rx) unit configured to receive a transmitted field from a reader device;
a matching network, the matching network configured to couple the receiver unit to an antenna;
an emulation control unit, the emulation control unit configured to emulate coupling change of the tag emulation device relative to the reader device by changing at least one configuration parameter of the tag emulation device and by not moving the tag emulation device relative to the reader device, wherein the at least one configuration parameter includes changing a phase of a transmitted signal from the tag emulation device versus a phase of a carrier signal of the transmitted field from the reader device, and wherein the emulated coupling change causes an impedance change of an antenna and matching network of the reader device.
16. The tag emulation device of claim 15 , wherein the coupling change corresponds to movement of the tag emulation device relative to the reader device.
17. The tag emulation device of claim 15 , wherein the coupling change corresponds to changing one of the following:
a position of the tag emulation device relative to the reader device,
an orientation of the tag emulation device relative to the reader device,
an antenna size of the tag emulation device and/or an antenna size of the reader device.
18. The tag emulation device of claim 15 further comprising:
a transmitter (Tx) unit, wherein the matching network is further configured to couple the transmitter unit to the antenna.
19. The tag emulation device of claim 18 ,
wherein the transmitter (Tx) unit is comprised of at least one Tx driver,
wherein the receiver (Rx) unit is comprised of a HF (high frequency) attenuator,
wherein the tag emulation device emulates coupling change of the tag emulation device relative to the reader device by changing one or more the following configuration parameters of the tag emulation device:
changing a Tx voltage,
changing a Tx driver impedance,
changing a HF attenuator resistance,
changing a Tx output modulation,
changing a matching network tuning,
enabling one or two Tx drivers.
20. The tag emulation device of claim 15 , wherein NFC stands for Near Field Communication, wherein the tag emulation device is a NFC-enabled device in one of the following modes:
ALM (active load modulation) card mode,
PLM (passive load modulation) card mode.