Backscatter interrogators, communication systems and backscatter communication methods

• US 20070290808A1
• Filed: 08/30/2007
• Published: 12/20/2007
• Est. Priority Date: 04/24/1998
• Status: Abandoned Application

• Current Assignee: Round Rock Research LLC
• Original Assignee: Round Rock Research LLC
• Inventors: Greeff, Roy, Ovard, David
• Application Number:
  US11/847,654
• Publication Number:
  US 20070290808A1
• Time in Patent Office: Days
• US Class Current: 340/10.1
• 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: 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 7/10366 the interrogation device being adapted for miscellaneous applications
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 7/22 Scatter propagation systems , e.g. ionospheric, tropospheric or meteor scatter
• CPC Class Codes: H04J 13/0022 PN, e.g. Kronecker

Abstract

The present invention provides backscatter interrogators, communication systems and backscatter communication methods. According to one aspect of the present invention, a backscatter interrogator includes a data path configured to communicate a data signal; a signal generator configured to generate a carrier signal; and a modulator coupled with the data path and the signal generator, the modulator being configured to spread the data signal to define a spread data signal and amplitude modulate the carrier signal using the spread data signal, the modulator being further configured to phase modulate the carrier signal.

Claims

1-47. -47. (canceled)

48. A method of operating an interrogator comprising:

encoding a first pseudo-noise sequence with a data signal to create a first spread data signal;

randomly inverting the first spread data signal using a second pseudo-noise sequence to create a second spread data signal, wherein one or more chips in the first spread data signal are inverted when the first spread data signal has a logical low value; and

creating a tri-state signal from the second pseudo-noise sequence and the second spread data signal.

49. The method of claim 48, further comprising:

reducing harmonic information within the tri-state signal using a low-pass filter; and

applying an output of the low-pass filter to an attenuator.

50. The method of claim 48, wherein randomly inverting the first spread data signal implements phase modulation.

51. The method of claim 48, further comprising:

modulating a carrier signal using the tri-state signal.

52. The method of claim 48, further comprising:

band limiting the first spread data signal.

53. The method of claim 48, further comprising:

inverting a phase of a carrier signal mixed with a negative value of the tri-state signal.

54. The method of claim 48 further comprising:

mixing a carrier signal with the tri-state signal.