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 Title: |
US6731908:
Distance measurement using half-duplex RF techniques
[ Derwent Title ]
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| Country: |
US United States of America
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| Inventor: |
Berliner, Shlomo; Rehovot, Israel
Holzkaner, Uri; Rehovot, Israel
Mirodin, Edward; Rehovot, Israel
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| Assignee: |
Bluesoft, Inc., San Mateo, CA
other patents from BLUESOFT, INC. (835924) (approx. 1)
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| Published / Filed: |
2004-05-04
/ 2001-01-16
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| Application Number: |
US2001000759602
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| IPC Code: |
Advanced:
G01S 13/84;
H04B 1/713;
IPC-7:
H04B 17/00;
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| ECLA Code: |
H04B1/7156; G01S13/84;
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| U.S. Class: |
Current:
455/067.11;
342/047;
342/127;
375/E01.037;
455/067.16;
455/456.1;
455/550.1;
Original:
455/067.11;
455/067.16;
455/550.1;
455/456.1;
342/047;
342/127;
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| Field of Search: |
455/67.11,67.14,67.16,76,115.1,502,507,550.1,404.2,456.1,456.6
342/047,127
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| Priority Number: |
| 2001-01-16 |
US2001000759602 |
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| Abstract: |
A system, apparatus, and method for determining the distance between two objects using an indirect propagation delay measurement is disclosed. A frequency hopping scheme (such as the Bluetooth(TM) technology) is used to measure the relative phase offset of the received signal between the various frequencies. For a given distance between the objects, the phase offset vs. frequency curve is a straight line with the slope dependent upon the measured distance. After the phase of the received signals is detected, the data is plotted on a curve and the slope is calculated.A wireless slave device remains phase locked with another device in a half-duplex communication mode by employing a low-drift phase locked loop employing a voltage controlled crystal oscillator. The phase locked loop further employs a mechanism that provides immunity from transitory phase slip at a time when the loop is opened.
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| Attorney, Agent or Firm: |
Harris, Andrew M. ;
Weiss, Harry M.Weiss, Moy & Harris, P.C. ;
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| Primary / Asst. Examiners: |
Urban, Edward F.; Nguyen, Simon
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| Maintenance Status: |
R1 Reinstated
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| INPADOC Legal Status: |
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Family Legal Status Report
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| Family: |
Show 5 known family members
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First Claim:
Show all 25 claims |
What is claimed is:
1. A half-duplex wireless remote device for use in a distance measurement system, comprising:
- a receiver for receiving a first radio frequency (RF) signal during a first time slot An from a wireless communication device, the first RF signal including a sequence of carriers fn, where n is a plurality of integers, wherein the sequence of carriers fn are phase coherent with a first reference signal generated at the wireless communication device, the receiver generating a second reference signal from the received first RF signal during the first time slot An, wherein the second reference signal is phase coherent with the received first RF signal;
- a phase locked loop (PLL) for generating a third reference signal synchronized in frequency and phase with the second reference signal;
- a synthesizer for generating a second RF signal, the second RF signal being phase coherent with the third reference signal and including a sequence of carriers corresponding to the carriers in of the first RF signal; and
- a transmitter for transmitting the second RF signal during a second time slot Bn, alternatingly repeat as n changes, and wherein said phase lock loop comprises a switched phase comparator for comparing the phase of the second and third reference signals and generating a phase output signal indicative of phase difference between the second and third RF signal, an integrator for filtering the phase output signal and generating a voltage signal, a voltage controlled oscillator (VCO) controlled by the voltage signal and generating a system clock, and a divider for dividing the frequency of the system clock by an integer N to generate the third reference signal, and wherein the third reference signal continues after the second reference signal is removed.
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| Background / Summary: |
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| Drawing Descriptions: |
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| Description: |
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| Forward References: |
Show 18 U.S. patent(s) that reference this one
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| Foreign References: |
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| Other Abstract Info: |
DERABS C2002-673651
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| Other References: |
The Official Bluetooth Website, 1 page. Internet source. Apr. 10, 2000.
Designing Cableless Devices with the Bluetooth Specification, 8 pages. Internet source. Apr. 10, 2000.
R.J. Palmer, "Test Results of a Precise, Short Range, RF Navigational/Positional System," IEEE Vehicle Navigation and Information Systems Conference (VNIS '89) (1st: 1989: Toronto), compiled and edited by D.H.M. Reekie, E.R. Case and J. Tsai, pp. 151-155.
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