Method and apparatus adapted to demodulate a data signal
View Patent ↗The present invention relates to the field of receiving data and/or demodulating a data transmission signal. The present invention provides a method of and/or device for determining a data signal imposed on a phase jitter modulation signal. In one form, the invention relates to the field of Radio Frequency Identification (RFID), and the transmission of data between a tag and an interrogator.
1. A method of determining a data signal imposed on a phase jitter modulation (PJM) signal, the method comprising the steps of:
providing a first phase jitter modulated signal;
applying a delay of less than one bit period to the first phase jitter modulated signal and obtaining a second phase jitter modulated signal;
comparing the first and second phase jitter modulated signals;
determining a phase difference as a result of the comparison between the first and second phase jitter modulated signals;
generating a recovery signal based on the comparison; and
reconstructing a data signal based on the recovery signal and an average DC value of the recovery signal.
2. The method as claimed in claim 1 , wherein the delay is a variable delay.
3. The method as claimed in claim 1 , wherein the phase difference is determined by an XOR gate.
4. The method as claimed in claim 1 , wherein the phase difference is determined by a mixer.
5. The method as claimed in claim 1 , wherein the phase difference is determined by a multiplier.
6. The method as claimed in claim 1 , wherein the phase difference is determined by a digital vernier circuit.
7. The method as claimed in claim 1 , wherein the delay is less than half of a bit period.
8. The method as claimed in claim 1 , wherein the delay is less than one quarter of a bit period.
9. The method as claimed in claim 1 , wherein the method is applied in an RFID system.
10. A device adapted to demodulate a data signal imposed on a phase jitter modulation (PJM) signal, comprising:
a receiver adapted to receive a first phase jitter modulated signal;
delay means adapted to apply a delay of less than one bit period to the first phase jitter modulated signal and obtain a second phase jitter modulated signal;
logic means adapted to compare the first and second phase jitter modulated signals, determine a phase difference as a result of the comparison between the first and second phase jitter modulated signals and generate a recovery signal based on the comparison; and
a window detector configured to receive the recovery signal to reconstruct a data signal based on the recovery signal and an average DC value of the recovery signal.
11. The device as claimed in claim 10 , wherein the delay is a variable delay.
12. The device as claimed in claim 10 , wherein the phase difference is determined by an XOR gate.
13. The device as claimed in claim 10 , wherein the phase difference is determined by a mixer.
14. The device as claimed in claim 10 , wherein the phase difference is determined by a multiplier.
15. The device as claimed in claim 10 , wherein the phase difference is determined by a digital vernier circuit.
16. The device as claimed in claim 10 , wherein the delay is less than half of a bit period.
17. The device as claimed in claim 10 , wherein the delay is less than one quarter of a bit period.
18. The device as claimed in claim 10 , wherein the device is an RFID device.
19. The device as claimed in claim 18 , wherein the device is a tag, transponder or interrogator.
20. A RFID system including a device, the device adapted to demodulate a data signal imposed on a phase jitter modulation (PJM) signal, the device comprising:
a receiver adapted to receive a first phase jitter modulated signal;
delay means adapted to apply a delay of less than one bit period to the first phase jitter modulated signal and obtain a second phase jitter modulated signal;
logic means adapted to compare the first and second phase jitter modulated signals, determine a phase difference as a result of the comparison between the first and second phase jitter modulated signals and generate a recovery signal based on the comparison; and
a window detector configured to receive the recovery signal to reconstruct a data signal based on the recovery signal and an average DC value of the recovery signal.