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

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.