Method and apparatus adapted to demodulate a data signal

• US 8,451,950 B2
• Filed: 09/08/2006
• Issued: 05/28/2013
• Est. Priority Date: 09/12/2005
• Status: Active Grant

• Current Assignee: SATO Holdings Corporation
• Original Assignee: Magellan Technology Pty. Ltd (SATO Holdings Corporation)
• Inventors: Murdoch, Graham Alexander Munro, Littlechild, Stuart Colin
• Primary Examiner(s): Liu, Shuwang
• Assistant Examiner(s): HUANG, DAVID S
• Application Number:
  US12/066,361
• Publication Number:
  US 20080267331A1
• Time in Patent Office: 2,454 Days
• Field of Search: 375/371, 375/316, 375/329, 340/10.1, 340/12.1, 340/12.11, 340/13.26
• US Class Current: 375/329
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: H03D 1/24 for demodulation of signals wherein one sideband or the carrier has been wholly or partially suppressed receiver circuits H04B1/302
• CPC Class Codes: H03D 3/02 by detecting phase difference between two signals obtained from input signal H03D3/28 - H03D3/32 take precedence; muting in frequency-modulation receivers H03G3/28; limiting arrangements H03G11/00
• CPC Class Codes: H03L 7/0812 and where no voltage or current controlled oscillator is used
• CPC Class Codes: H03L 7/0816 the controlled phase shifter and the frequency- or phase-detection arrangement being connected to a common input
• CPC Class Codes: H04L 25/4902 Pulse width modulation; Pulse position modulation
• CPC Class Codes: H04L 27/2331 wherein the received signal is demodulated using one or more delayed versions of itself

Abstract

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.

Claims

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.