Demodulating module, RFID system utilizing the demodulating module and method thereof

• US 7,999,678 B2
• Filed: 11/10/2008
• Issued: 08/16/2011
• Est. Priority Date: 12/14/2007
• Status: Active Grant

• Current Assignee: Xueshan Technologies Inc. (Wi-LAN Inc.)
• Original Assignee: MStar Semiconductor Incorporated (MediaTek, Inc.)
• Inventors: Chen, Chien-Sheng
• Primary Examiner(s): Previl; Daniel
• Application Number:
  US12/268,426
• Publication Number:
  US 20090153330A1
• Time in Patent Office: 1,009 Days
• Field of Search: 3405721-5729, 340/539.1, 340/568.1, 340/539.13, 340/546
• US Class Current: 340/572.1
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10297 arrangements for handling protocols designed for non-contact record carriers such as RFIDs NFCs, e.g. ISO/IEC 14443 and 18092 cryptographic protocols H04L9/00; network security protocols H04L63/00; real-time communication protocols in data switching networks H04L65/00; network protocols for data switching network services H04L67/00

Abstract

A demodulating module includes: a processing unit, for generating a control signal; and a demodulator, coupled to the processing unit and stored with a plurality of correlative coefficient masks, for receiving a data signal, selecting one of the correlative coefficient masks according to the control signal, generating a demodulated signal according to the data signal and the selected correlative coefficient mask, and transmitting the demodulated signal to the processing unit.

Claims

1. An RFID system, comprising:

an antenna, for receiving an RF signal;

an RFID front end module, for transforming the RF signal into a data signal;

a processing unit, for generating a control signal; and

a demodulator, coupled to the processing unit and stored with a plurality of correlative coefficient masks, for receiving a data signal, selecting one of the correlative coefficient masks according to the control signal, generating a demodulated signal according to the data signal and the selected correlative coefficient mask, and transmitting the demodulated signal to the processing unit.

2. The RFID system of claim 1, wherein the correlative coefficient masks correspond to different communication protocols.

3. The RFID system of claim 1, wherein the demodulator comprises:

a storage unit, coupled to the processing unit, for storing the correlative coefficient masks;

a latch, for latching a part of the data signal to form a first data group;

a first correlation judging unit, coupled to the latch and the storage unit, for judging, according to a first correlative coefficient mask of the correlative coefficient masks, correlation between the first data group and the first correlative coefficient mask to output a first judging value;

a second correlation judging unit, coupled to the latch and the storage unit, for judging, according to a second correlative coefficient mask of the correlative coefficient masks, correlation between the first data group and the second correlative coefficient mask to output a second judging value; and

a comparator, for comparing the first judging value and the second judging value to generate corresponding data as the demodulated signal.

4. The RFID system of claim 3, wherein the demodulator further comprises:

a data packer, for collecting a plurality of sets of the corresponding data to form a second data group with a predetermined size, the second data group to be used as the demodulated signal and provided to the processing unit.

5. The RFID system of claim 3, wherein the first data group further comprises an auxiliary judging region and a data region, the storage unit further stores a plurality of auxiliary judging masks, and the first correlation judging unit or the second correlation judging unit further judges, according to a predetermined auxiliary judging mask of the auxiliary judging masks, correlation between the auxiliary judging region and the predetermined auxiliary judging mask to determine a position of the data region.

6. The RFID system of claim 3, wherein the first correlation judging unit and the second correlation judging unit are implemented by an adder or a multiplexer.

7. A demodulating module, comprising:

a processing unit, for generating a control signal; and

a demodulator, coupled to the processing unit and stored with a plurality of correlative coefficient masks, for receiving a data signal, selecting one of the correlative coefficient masks according to the control signal, generating a demodulated signal according to the data signal and the selected correlative coefficient mask, and transmitting the demodulated signal to the processing unit.

8. The demodulating module of claim 7, being used for an RFID system.

9. The demodulating module of claim 7, wherein the correlative coefficient masks correspond to different communication protocols.

10. The demodulating module of claim 7, wherein the demodulator comprises:

a storage unit, coupled to the processing unit, for storing the correlative coefficient masks;

a latch, for latching a part of the data signal to form a first data group;

a first correlation judging unit, coupled to the latch and the storage unit, for judging, according to a first correlative coefficient mask of the correlative coefficient masks, correlation between the first data group and the first correlative coefficient mask to output a first judging value;

a second correlation judging unit, coupled to the latch and the storage unit, for judging, according to a second correlative coefficient mask in the correlative coefficient masks, correlation between the first data group and the second correlative coefficient mask to output a second judging value; and

a comparator, for comparing the first judging value and the second judging value to generate corresponding data as the demodulated signal.

11. The demodulating module of claim 10, wherein the demodulator further comprises:

a data packer, for collecting a plurality of sets of the corresponding data to form a second data group with a predetermined size, the second data group to be used as the demodulated signal and provided to the processing unit.

12. The demodulating module of claim 10, wherein the first data group further comprises an auxiliary judging region and a data region, the storage unit further stores a plurality of auxiliary judging masks, and the first correlation judging unit or the second correlation judging unit further judges, according to a predetermined auxiliary judging mask of the auxiliary judging masks, correlation between the auxiliary judging region and the predetermined auxiliary judging mask to determine a position of the data region.

13. The demodulating module of claim 10, wherein the first correlation judging unit and the second correlation judging unit are implemented by an adder or a multiplexer.

14. A demodulating method, comprising steps of:

(a) providing a plurality of correlative coefficient masks;

(b) receiving a data signal;

(c) selecting one of the correlative coefficient masks; and

(d) generating a demodulated signal according to the data signal and the selected correlative coefficient mask.

15. The demodulating method of claim 14, being used for an RFID system.

16. The demodulating method of claim 14, wherein the correlative coefficient masks correspond to different communication protocols.

17. The demodulating method of claim 14, wherein the step (d) comprises steps of:

(d1) latching a part of the data signal to form a first data group;

(d2) judging, according to a first correlative coefficient mask of the correlative coefficient masks, correlation between the first data group and the first correlative coefficient mask to output a first judging value;

(d3) judging, according to a second correlative coefficient mask of the correlative coefficient masks, correlation between the first data group and the second correlative coefficient mask to output a second judging value; and

(d4) comparing the first judging value and the second judging value to generate corresponding data as the demodulated signal.

18. The demodulating method of claim 17, further comprising a step of:

collecting a plurality of sets of the corresponding data to form a second data group with a predetermined size, the second data group to be used as the demodulated signal.

19. The demodulating method of claim 17, wherein the first data group further comprises an auxiliary judging region and a data region, and the method further comprises steps of:

providing a plurality of auxiliary judging masks; and

judging, according to a predetermined auxiliary judging mask of the auxiliary judging masks, correlation between the auxiliary judging region and the predetermined auxiliary judging mask to determine a position of the data region.

20. The demodulating method of claim 17, wherein the step (d2) or (d3) utilizes an adder or a multiplier.