Interrogators communication systems communication methods and methods of processing a communication signal

• US 6,324,211 B1
• Filed: 04/24/1998
• Issued: 11/27/2001
• Est. Priority Date: 04/24/1998
• Status: Expired due to Term

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Ovard, David K., Greeff, Roy
• Primary Examiner(s): LUTHER, WILLIAM A
• Application Number:
  US09/066,738
• Time in Patent Office: 1,313 Days
• Field of Search: 375/219, 375/220, 375/221, 340/572, 340/573, 340/824.54, 324/76.39, 324/76.17, 324/76.21, 324/76.41, 324/76.55, 324/76.82, 324/77.11, 342/51, 342/44, 342/50, 455/106, 455/73, 455/517, 455/38.2, 455/54.1, 455/49.1, 455/54.2, 455/19, 370/18, 370/95.3
• US Class Current: 375/219
• 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: H03D 3/00 Demodulation of angle-, frequency- or phase- modulated oscillations H03D5/00, H03D9/00, H03D11/00 take precedence

Abstract

The present invention includes interrogators, communication systems, communication methods, and methods of processing a communication signal. One aspect of the present invention provides a backscatter system interrogator including a downconverter configured to receive a backscatter communication signal having a first frequency and convert the backscatter communication signal having the first frequency to a subcarrier signal having a second frequency less than the first frequency; a filter coupled with the downconverter and configured to filter direct path energy from the subcarrier signal; and a gain control coupled with the filter and configured to adjust the gain of the filtered subcarrier signal.

Claims

1. An interrogator comprising:

a downconverter configured to convert a communication signal to an in-phase signal and a quadrature signal;

filters coupled with the downconverter and individually configured to filter direct path energy from one of the in-phase signal and the quadrature signal; and

gain controls coupled with respective filters and the gain controls being individually configured to adjust the gain of one of the in-phase signal and the quadrature signal.

2. The interrogator according to claim 1 wherein the downconverter is configured to convert a microwave communication signal to the in-phase signal and the quadrature signal.

3. The interrogator according to claim 1 wherein the interrogator comprises an interrogator of a backscatter communication system.

4. The interrogator according to claim 1 wherein the gain controls are configured to maintain the amplitude of the in-phase signal relative to the amplitude of the quadrature signal.

5. The interrogator according to claim 1 wherein the filters comprise band pass filters.

6. The interrogator according to claim 1 wherein the in-phase signal and the quadrature signal individually having a subcarrier frequency.

7. The interrogator according to claim 6 wherein the filters are configured to filter the in-phase signal and the quadrature signal about the subcarrier frequency.

8. The interrogator according to claim 1 wherein the filters are individually configured to band limit one of the in-phase signal and the quadrature signal.

9. The interrogator according to claim 1 wherein the gain controls comprise automatic gain controls.

54. The interrogator according to claim 1 wherein the filters are individually configured to filter direct path energy from one of the in-phase signal and quadrature signal comprising an analog signal.

10. A backscatter system interrogator comprising:

a downconverter configured to receive a backscatter communication signal having a first frequency and convert the backscatter communication signal having the first frequency to a subcarrier signal having a second frequency less than the first frequency;

a filter coupled with the downconverter and configured to filter direct path energy from the subcarrier signal; and

a gain control coupled with the filter and configured to adjust the gain of the filtered subcarrier signal.

11. The backscatter system interrogator according to claim 10 wherein the first frequency is a microwave frequency.

12. The backscatter system interrogator according to claim 10 wherein the gain control comprises an automatic gain control.

13. The backscatter system interrogator according to claim 10 wherein the gain control comprises cascaded automatic gain controls.

14. The backscatter system interrogator according to claim 10 where the filters comprise band pass filters.

55. The backscatter system interrogator according to claim 10 wherein the filter is configured to filter direct path energy from the subcarrier signal comprising an analog signal.

15. A backscatter system interrogator comprising:

a downconverter configured to convert a communication signal to an in-phase signal and a quadrature signal;

gain controls coupled with the downconverter and individually configured to adjust the gain of one of the in-phase signal and the quadrature signal; and

a controller coupled with the gain controls and configured to output a control signal to the gain controls to control adjustment of the gain of the in-phase signal and the quadrature signal.

16. The backscatter system interrogator according to claim 15 wherein the controller is configured to maintain the amplitudes of the in-phase signal and the quadrature signal relative to one another during the adjustment of the gain.

17. The backscatter system interrogator according to claim 15 wherein the gain controls individually comprise cascaded automatic gain controls.

18. The backscatter system interrogator according to claim 15 further comprising filters coupled with the downconverter and individually configured to remove direct path energy from one of the in-phase signal and the quadrature signal.

19. The backscatter system interrogator according to claim 15 wherein the controller is configured to output the control signal corresponding to one of the in-phase signal and the quadrature signal having a greater amplitude.

56. The backscatter system interrogator according to claim 15 wherein the gain controls are individually configured to adjust the gain of one of the in-phase and the quadrature signal comprising an analog signal.

20. A communication system comprising:

an electronic communication device configured to output a communication signal; and

an interrogator configured to receive the communication signal, the interrogator being configured to downconvert the communication signal to a subcarrier signal and filter direct path energy from the subcarrier signal, the interrogator being further configured to adjust the gain of the subcarrier signal.

21. The communication system according to claim 20 wherein the communication system comprises a backscatter communication system.

22. The communication system according to claim 20 wherein the communication signal comprises a microwave communication signal.

23. The communication system according to claim 20 wherein the interrogator is configured to downconvert the communication signal to an in-phase signal and a quadrature signal.

24. The communication system according to claim 23 wherein the interrogator is configured to band limit the in-phase signal and the quadrature signal about a frequency of the subcarrier signal.

25. The communication system according to claim 23 wherein the interrogator is configured to adjust the gain of the in-phase signal and the quadrature signal using a common control signal.

57. The communication system according to claim 20 wherein the interrogator is configured to filter direct path energy from the subcarrier signal comprising an analog signal.

26. A backscatter communication system comprising:

an electronic communication device configured to output a microwave reply signal responsive receiving a microwave command signal; and

an interrogator configured to output the microwave command signal and receive the microwave reply signal and downconvert the reply signal to an in-phase signal and a quadrature signal individually having a subcarrier frequency, the interrogator being configured to band pass filter the in-phase signal and the quadrature signal comprising analog signals about the respective subcarrier frequencies to remove direct path energy, the interrogator being further configured to generate a control signal corresponding to one of the in-phase signal and quadrature signal having a greater amplitude, and adjust the gain of the in-phase signal and the quadrature signal using the control signal.

27. A communication method comprising:

outputting a command signal;

receiving a reply signal responsive to the outputting the command signal;

downconverting the reply signal to a subcarrier signal;

removing direct path energy from the subcarrier signal; and

adjusting the gain of the subcarrier signal.

28. The method according to claim 27 wherein the removing comprises band pass filtering the reply signal about frequency of the subcarrier signal.

29. The method according to claim 27 wherein the receiving comprises receiving a microwave signal.

30. The method according to claim 27 wherein the downconverting provides an in-phase signal and a quadrature signal.

58. The method according to claim 27 wherein the removing comprises removing direct path energy from the subcarrier signal comprising an analog signal.

31. A backscatter communication method comprising:

receiving a backscatter communication signal;

downconverting the backscatter communication signal to an in-phase signal and a quadrature signal;

generating a control signal; and

adjusting the gain of the in-phase signal and the quadrature signal using the control signal, wherein the amplitudes of the in-phase signal and the quadrature signal are maintained relative to one another during the adjusting.

32. The method according to claim 31 wherein the generating corresponds to one of the in-phase signal and the quadrature signal having the greater amplitude.

33. The method according to claim 31 further comprising filtering the in-phase signal and the quadrature signal.

34. The method according to claim 31 further comprising removing direct path energy from the in-phase signal and the quadrature signal prior to the adjusting.

35. The method according to claim 31 further comprising band pass filtering the in-phase signal and the quadrature signal comprising analog signals about respective subcarrier frequencies of the in-phase signal and the quadrature signal.

59. The method according to claim 31 wherein the adjusting comprises adjusting the gain of the in-phase signal and the quadrature signal comprising analog signals.

36. A backscatter communication method comprising:

outputting a microwave command signal;

receiving a microwave backscatter signal responsive to the outputting the command signal;

downconverting the backscatter signal to an in-phase signal and a quadrature signal individually having a subcarrier frequency;

filtering the in-phase signal and the quadrature signal comprising analog signals about the respective subcarrier frequencies to remove direct path energy from the in-phase signal and the quadrature signal;

generating a gain control signal corresponding to one of the in-phase signal and quadrature signal having a greater amplitude; and

adjusting the gain of the in-phase signal and the quadrature signal using the gain control signal.

37. A method of processing a communication signal, the method comprising:

receiving a communication signal;

downconverting the communication signal to an in-phase signal and a quadrature signal;

removing direct path energy from the in-phase signal and the quadrature signal;

generating a gain control signal; and

adjusting the gain of the in-phase signal and the quadrature signal using the gain control signal.

38. The method according to claim 37 wherein the receiving comprises receiving a backscatter communication signal.

39. The method according to claim 37 wherein the receiving comprises receiving a microwave communication signal.

40. The method according to claim 37 wherein the in-phase signal and the quadrature signal individually have a subcarrier frequency and the removing comprises band pass filtering about the subcarrier frequency.

41. The method according to claim 40 wherein the receiving comprises receiving a backscatter communication signal.

42. The method according to claim 37 further comprising maintaining the amplitude of the in-phase signal relative to the amplitude of the quadrature signal during the adjusting.

43. The method according to claim 37 wherein the generating corresponds to one of the in-phase signal and the quadrature signal having a greater amplitude.

60. The method according to claim 37 wherein the removing comprises filtering the in-phase signal and the quadrature signal comprising analog signals.

44. A method of processing a communication signal, the method comprising:

receiving a communication signal;

downconverting the communication signal to an in-phase signal and a quadrature signal;

removing direct path energy from the in-phase signal and the quadrature signal; and

adjusting the gain of the in-phase signal and the quadrature signal.

45. The method according to claim 44 further comprising maintaining the amplitude of the in-phase signal relative to the amplitude of the quadrature signal during the adjusting.

46. The method according to claim 44 wherein the downconverting comprises downconverting the communication signal to the in-phase signal and the quadrature signal individually having a subcarrier frequency.

47. The method according to claim 46 wherein the removing comprises band pass filtering about the subcarrier frequency.

48. The method according to claim 47 wherein the receiving comprises receiving a backscatter communication signal.

49. The method according to claim 44 wherein the adjusting comprises adjusting the gain following the removing.

50. The method according to claim 44 wherein the adjusting the gain comprises adjusting using automatic gain controls.

51. The method according to claim 44 wherein the adjusting comprises using a common control signal corresponding to one of the in-phase signal and the quadrature signal having a greater amplitude.

52. The method according to claim 44 further comprising increasing the dynamic range of the in-phase signal and the quadrature signal using cascaded automatic gain controls.

53. The method according to claim 44 wherein the receiving comprises receiving a backscatter communication signal.

61. The method according to claim 44 wherein the removing comprises filtering the in-phase signal and the quadrature signal comprising analog signals.