RFID READER

• US 20070041476A1
• Filed: 08/10/2006
• Published: 02/22/2007
• Est. Priority Date: 08/16/2005
• Status: Active Grant

• Current Assignee: LS Industrial Systems Company Limited
• Original Assignee: LS Industrial Systems Company Limited
• Inventors: Seon, Jong-Kug
• Granted Patent: US 7,889,057 B2
• Time in Patent Office: Days
• US Class Current: 375/340
• CPC Class Codes: H04L 25/03834 using pulse shaping
• CPC Class Codes: H04L 27/04 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 27/06 Demodulator circuits; Receiver circuits

Abstract

Provided are an RFID reader reading data from an RFID tag using a wireless connection over a specified frequency bandwidth, including a transmitting unit synthesizing sequentially and cumulatively frequency control signals generated every clock, mixing the synthesized specific frequency signal and a fixed frequency signal, and as a result outputting an RF signal.

Claims

1. An RFID reader reading data from an RFID tag using a wireless connection over a specified frequency bandwidth, comprising an transmitting unit sequentially and cumulatively synthesizing frequency control signals generated every clock, mixing the synthesized specific frequency signal and a fixed frequency signal, and as a result outputting an RF signal.

2. The RFID reader of claim 1, wherein the transmitting unit comprises:

a frequency synthesizing unit synthesizing sequentially and cumulatively frequency control signals generated every clock and as a result outputting a specific frequency signal;

a fixed frequency generating unit generating a frequency fixed to a specified level and outputting the fixed frequency;

a modulating unit modulating the specific frequency signal output from the frequency synthesizing unit and the fixed frequency outputted from the fixed frequency and as a result outputting an RF signal; and

an amplifying unit amplifying the RF signal output from the modulating unit to a specific level and transmitting the amplified signal through an antenna.

3. The RFID reader of claim 2, wherein the frequency synthesizing unit is a direct digital frequency synthesizer.

4. The RFID reader of claim 3, wherein the direct digital frequency synthesizer comprises:

an accumulator adding the frequency control signal generated every clock to a stored value;

a ROM storing a digitized sine value corresponding to a phase of the signal output from the accumulator; and

a digital-to-analog converter converting the digital value selected from the ROM into an analog value.

5. The RFID reader of claim 2, further comprising a controlling unit outputting the frequency control signal which is converted into a digital signal every clock and controlling a fixation of the frequency to a specific level.

6. The RFID reader of claim 1, wherein the modulating unit comprises:

a first phase shifting unit phase-shifting the specific frequency signal by 90 degrees and as a result outputting an in-phase signal;

a second phase shifting unit phase-shifting the fixed frequency signal by 90 degrees;

a first mixer mixing the in-phase signal from the first phase shifting unit and the signal output from the second phase shifting unit;

a second mixer mixing the fixed frequency and a quadrature-phase signal of the signal having the specific frequency; and

an adding unit adding a signal output from the first mixer and a signal output from the second mixer and as a result outputting the RF signal.

7. The RFID reader of claim 4, wherein the digital-to-analog converter performs pulse shaping through adjusting ascending and descending times of the digital value output from the ROM to a specific level and as a result outputs an analog signal as a specific frequency signal.

8. An RFID reader reading data from an RFID tag using a wireless connection over a specified frequency bandwidth, comprising a receiving unit mixing a signal received from the RFID tag and a fixed frequency signal, converting a mixed signal into a digital signal and as a result extracting data.

9. The RFID reader of claim 8. wherein the receiving unit comprises:

a demodulating unit mixing the signal transmitted from the RFID tag and the fixed frequency and demodulating the mixed signal and frequency; and

a data extracting unit converting a demodulated signal output from the demodulating unit into the digital signal and as a result extracting the data.

10. The RFID reader of claim 9, wherein the demodulating unit comprises:

a low noise amplifying unit amplifying the signal received from the RFID tag to a low noise level; and

a third mixer mixing a signal output from the low noise amplifying unit and the fixed frequency.

11. The RFID reader of claim 9, wherein the data extracting unit comprises:

a low pass filter passing a demodulated signal output from the demodulating unit, which is below a certain level;

an amplifying unit amplifying a signal output from the low pass filter to a specific level;

a high pas filter passing an amplified signal output from the amplifying unit, which is above a certain level; and

an analog-to-digital converter converting a signal output from the high pass filter into a digital signal.

12. The RFID reader of claim 9, wherein the data extracting unit comprises:

a low pass filter passing a demodulated signal output from the demodulating unit, which is below a certain level;

an amplifying unit amplifying a signal output from the low pass filter to a specific level;

a high pas filter passing an amplified signal output from the amplifying unit, which is above a certain level; and

a data slicer cutting off a signal output from the high pass filter which is above or below a specified level and converting the signal of the specified level into a digital signal.

13. An RFID reader reading data from an RFID tag using a wireless connection over a specified frequency bandwidth comprising:

a transmitting unit synthesizing sequentially and cumulatively frequency control signals generated every clock, mixing the synthesized specific frequency signal and a fixed frequency signal, and as a result outputting an RF signal, and

a receiving unit mixing a signal received from the RFID tag and the fixed frequency signal, converting a mixed signal into a digital signal, and as a result extracting data.

14. The RFID reader of claim 13, wherein the transmitting unit comprises:

a frequency synthesizing unit synthesizing sequentially and cumulatively frequency control signals generated every clock and as a result outputting a specific frequency signal;

a fixed frequency generating unit generating a fixed frequency to a specific level depending a certain control;

a modulating unit modulating a specific frequency signal output from the frequency synthesizing unit and a fixed frequency output from the fixed frequency generating unit and as a result outputting the RF signal; and

an amplifying unit amplifying the RF signal output from the modulating unit to a specific level and transmitting the amplified RF signal through an antenna.

15. The RFID reader of claim 13, wherein the receiving unit comprises:

a demodulating unit mixing the signal transmitted from the RFID tag and a fixed frequency and demodulating the mixed signal and fixed frequency; and

a data extracting unit converting a demodulated signal output from the demodulating unit into a digital signal and as a result extracting the data.

16. An RFID reader reading data from an RFID tag using a wireless connection over a specified frequency bandwidth, comprising:

a transmitting unit pulse-shaping a frequency control signal generated every clock, mixing the pulse-shaped specific frequency signal and a changed frequency and as a result, outputting an RF signal; and

a controlling unit outputting the frequency control signal which is converted into a digital signal every clock and controlling a change of a changed frequency to synchronize phases of the specific frequency signal and changed frequency.

17. The RFID reader of claim 16, wherein the transmitting unit comprises:

a pulse shaping unit performing pulse shaping through adjusting of ascending and descending times of the frequency control signal generated every clock and as a result outputting a specific frequency signal;

a frequency changing unit changing a changed frequency to synchronize phases of the specific frequency signal and the changed frequency depending on a specific control;

a modulating unit mixing the changed frequency output from the frequency changing unit and the specific frequency signal output from the pulse shaping unit and modulating a mixed changed frequency and specific frequency signal; and

an amplifying unit amplifying a signal output from the modulating unit to a specific level and transmitting an amplified signal through an antenna.

18. The RFID reader of claim 17, wherein the modulating unit comprises:

a phase shifting unit phase-shifting the changed frequency by 90 degrees;

a first mixer mixing a specific frequency signal output from the pulse shaping unit and a signal output from the phase shifting unit;

a second mixer the specific frequency signal output form the pulse shaping unit and the changed frequency; and

an adding unit adding a signal output from the first mixer and a signal output from the second mixer and as a result outputting the RF signal.

19. An RFID reader reading data from an RFID tag using a wireless connection over a specified frequency bandwidth, comprising a receiving unit mixing a frequency of a signal transmitted from the RFID tag by way of squaring the frequency of the signal, converting a mixed signal into a digital signal, and as a result extracting data.

20. The RFID reader of claim 19, wherein the receiving unit comprises:

a demodulating unit mixing the frequency of the signal transmitted from the RFID tag by way of squaring the frequency; and

a data extracting unit converting a mixed signal output from the demodulating unit into a digital signal and as a result extracting the data.

21. The RFID reader of claim 20, wherein the demodulating unit comprises:

a low noise amplifying unit amplifying the signal transmitted from the RFID tag to a low noise level; and

a mixer mixing a frequency of a signal output from the low noise amplifying unit by way of squaring the frequency.

22. The RFID reader of claim 21, wherein the data extracting unit comprises:

a low pass filter passing a demodulated signal output from the demodulating unit, which is below a certain level;

an amplifying unit amplifying a signal output from the low pass filter to a specific level;

a high pas filter passing an amplified signal output from the amplifying unit, which is above a certain level; and

an analog-to-digital converter converting a signal output from the high pass filter into a digital signal.

23. The RFID reader of claim 21, wherein the data extracting unit comprises:

a low pass filter passing a demodulated signal output from the demodulating unit, which is below a certain level;

an amplifying unit amplifying a signal output from the low pass filter to a specific level;

a high pas filter passing an amplified signal output from the amplifying unit, which is above a certain level; and

a data slicer cutting off a signal output from the high pass filter which is above or below a specified level and converting the signal of the specific level into a digital signal.

24. An RFID reader reading data from an RFID tag using a wireless connection over a specified frequency bandwidth, comprising:

a transmitting unit pulse-shaping a frequency control signal generated every clock, mixing the pulse-shaped specific frequency signal and a changed frequency, and as a result outputting an RF signal; and

a receiving unit mixing a frequency of a signal transmitted from the RFID tag by way of squaring the frequency, converting the mixed signal into a digital signal, and as a result extracting data.

25. The RFID reader of claim 24, wherein the transmitting unit comprises:

a pulse shaping unit performing pulse shaping through adjusting of ascending and descending times of the frequency control signal generated every clock and as a result outputting a specific frequency signal;

a frequency changing unit changing a changed frequency to synchronize phases of the specific frequency signal and the changed frequency depending on a specific control;

a modulating unit mixing the changed frequency output from the frequency changing unit and the specific frequency signal output from the pulse shaping unit and modulating a mixed changed frequency and specific frequency signal; and

an amplifying unit amplifying a signal output from the modulating unit to a specific level and transmitting an amplified signal through an antenna.

26. The RFID reader of claim 25, wherein the modulating unit comprises:

a phase shifting unit phase-shifting the changed frequency by 90 degrees;

a first mixer mixing a specific frequency signal output from the pulse shaping unit and a signal output from the phase shifting unit;

a second mixer the specific frequency signal output form the pulse shaping unit and the changed frequency; and

an adding unit adding a signal output from the first mixer and a signal output from the second mixer and as a result outputting the RF signal.

27. The RFID reader of claim 25, wherein the receiving unit comprises:

a demodulating unit mixing the signals transmitted from the RFID tag by way of squaring the signals; and

a data extracting unit converting a mixed signal output from the demodulating unit into a digital signal and as a result extracting the data.

28. A RFID reader reading data from an RFID tag using a wireless connection over a specified frequency bandwidth comprising a receiving unit detecting a level of a signal received from the RFID tag, converting the detected level of the signal into a digital signal, and as a result extracting data.

29. The RFID reader of claim 28, wherein the receiving unit comprises:

a demodulating unit processing a frequency of the signal transmitted from the RFID tag using the root-mean-square method and as a result detecting a processed value as a demodulated signal; and

a data extracting unit converting the demodulated signal output from the demodulating unit into a digital signal and as a result extracting the data.

30. The RFID reader of claim 28, wherein the demodulating unit comprises:

a low noise amplifying unit amplifying the signal transmitted from the RFID tag to a low noise level; and

a level detecting unit squaring a frequency of a signal output from the low noise amplifying unit, integrating the squared frequency of the signal, and outputting an average value of the integrated signal as a demodulated signal.

31. The RFID reader of claim 29, wherein the data extracting unit comprises:

a low pass filter passing a demodulated signal output from the demodulating unit, which is below a certain level;

an amplifying unit amplifying a signal output from the low pass filter to a specific level;

a high pas filter passing an amplified signal output from the amplifying unit, which is above a certain level; and

an analog-to-digital converter converting a signal output from the high pass filter into a digital signal.

32. The RFID reader of claim 30, wherein the data extracting unit

a low pass filter passing a demodulated signal output from the demodulating unit, which is below a certain level;

an amplifying unit amplifying a signal output from the low pass filter to a specific level;

a high pas filter passing an amplified signal output from the amplifying unit, which is above a certain level; and

a data slicer cutting off a signal output from the high pass filter which is above or below a specified level and converting the signal of the specific level into a digital signal.

33. A RFID reader reading data from an RFID tag using a wireless connection over a specified frequency bandwidth, comprising:

a transmitting unit pulse-shaping a frequency control signal generated every clock, mixing the pulse-shaped specific frequency signal and a changed frequency, and as a result outputting an RF signal; and

a receiving unit detecting a level of a signal received from the RFID tag, converting a detected level of the signal into a digital signal and as a result extracting data.

34. The RFID reader of claim 33, wherein the receiving unit

a pulse shaping unit performing pulse shaping through adjusting of ascending and descending times of the frequency control signal generated every clock and as a result outputting a specific frequency signal;

a frequency changing unit changing a changed frequency to synchronize phases of the specific frequency signal and the changed frequency depending on a specific control;

a modulating unit mixing the changed frequency output from the frequency changing unit and the specific frequency signal output from the pulse shaping unit and modulating a mixed changed frequency and specific frequency signal; and

an amplifying unit amplifying a signal output from the modulating unit to a specific level and transmitting an amplified signal through an antenna.

35. The RFID reader of claim 33, wherein the receiving unit comprises:

a demodulating unit processing a frequency of the signal transmitted from the RFID tag using the RMS method and as a result detecting a processes value as a demodulated signal; and

a data extracting unit converting the demodulated signal output from the demodulating unit into a digital signal and as a result extracting the data.

36. The RFID reader of claim 35, wherein the demodulating unit comprises:

a low noise amplifying unit amplifying the signal transmitted from the RFID tag to a low noise level; and

a level detecting unit squaring a frequency of a signal output from the low noise amplifying unit, integrating the squared frequency of the signal, and outputting an average value of the integrated signal as a demodulated signal.