Variable length correlator

• US 8,774,329 B2
• Filed: 06/21/2011
• Issued: 07/08/2014
• Est. Priority Date: 07/01/2010
• Status: Active Grant

• Current Assignee: Zest Labs, Inc.
• Original Assignee: Intelleflex Corporation
• Inventors: Kawaguchi, Dean
• Primary Examiner(s): Malek, Leila
• Application Number:
  US13/165,726
• Publication Number:
  US 20120002760A1
• Time in Patent Office: 1,113 Days
• Field of Search: 375/343, 375/340, 375/316, 708/422, 708/813
• US Class Current: 375/343
• 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: H04Q 2213/13095 PIN / Access code, authentication

Abstract

A method for processing a signal derived from a radio frequency signal at some rate in a range of allowable data rates according to one embodiment includes downconverting an incoming signal derived from a radio frequency signal to complex near-baseband signals; processing the complex near-baseband signals in two data correlators corresponding to data 0 and data 1; and changing effective lengths of the correlators based on a symbol data rate of the incoming signal. Such methodology may also be implemented as a system using logic for performing the various operations. Additional systems and methods are also presented.

Claims

1. A method for processing a signal derived from a radio frequency signal at some rate in a range of allowable data rates, the method comprising:

downconverting an incoming signal derived from a radio frequency signal to complex near-baseband signals;

processing the complex near-baseband signals in two data correlators corresponding to data 0 and data 1; and

changing effective lengths of the correlators based on a symbol data rate of the incoming signal,

wherein each correlator includes a series of windowed integrators that are configurable for different lengths.

2. The method of claim 1, wherein the outputs of the windowed integrators of each correlator are added in one path and subtracted in another path and processed by complex-to-magnitude modules to generate data signals, wherein the data signals are kept separate until after outputs of the complex-to-magnitude modules.

3. The method of claim 1, wherein each of the windowed integrators of each correlator is a half symbol integrator correlator, wherein correlator variable delay modules provide a delay into two of the windowed integrators, wherein no delay is introduced into another two of the windowed integrators.

4. The method of claim 1, wherein the correlator outputs are combined to create a combined correlator magnitude signal, and further comprising using the combined correlator magnitude signal to determine an end of a signal modulation.

5. A system, comprising:

hardware logic for downconvering an incoming signal derived from a radio frequency signal to complex near-baseband signals; and

two data correlators corresponding to data 0 and data 1 for processing the complex near-baseband signals,

wherein the correlators each have a variable effective length which is changeable based on a symbol data rate of the incoming signal,

wherein each correlator is a Tbit windowed integrator, wherein Tbit is a duration of a data symbol and is variable over a predetermined range, and where a residual subcarrier frequency on the near-baseband signal input to each correlator is small relative to the data rate.

6. A system, comprising:

hardware logic configured to downconvert an incoming signal derived from a radio frequency signal to complex near-baseband signals; and

two data correlators corresponding to data 0 and data 1 for processing the complex near-baseband signals;

wherein the correlators each have a variable effective length which is changeable based on a symbol data rate of the incoming signal,

wherein each correlator includes a series of windowed integrators that are configurable for different lengths.

7. The system of claim 6, wherein the outputs of the windowed integrators of each correlator are added in one path and subtracted in another path and processed by complex to magnitude modules to generate data signals, wherein the data signals are kept separate until after outputs of the complex to magnitude modules.

8. The system of claim 6, wherein each of the windowed integrators of each correlator is a half symbol integrator correlator, wherein correlator variable delay modules provide a delay into two of the windowed integrators, wherein no delay is introduced.

9. The system of claim 6, wherein the correlator outputs are combined to create a combined correlator magnitude signal, and further comprising using the combined correlator magnitude signal to determine an end of a signal modulation.

10. The system of claim 6, further comprising at least one antenna for receiving the radio frequency signal.