Method and system for determining a time delay between transmission and reception of an RF signal in a noisy RF environment using phase detection

• US 7,826,800 B2
• Filed: 11/27/2007
• Issued: 11/02/2010
• Est. Priority Date: 11/27/2006
• Status: Expired due to Fees

• Current Assignee: ORTHOsoft ULC. (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Orthosoft Inc. (Zimmer Biomet Holdings, Inc.)
• Inventors: Laroche, Jean-Louis
• Primary Examiner(s): PHAM, TUAN
• Application Number:
  US11/945,641
• Publication Number:
  US 20080125054A1
• Time in Patent Office: 1,071 Days
• Field of Search: 455/67.16, 455/452.2, 455/23, 455/42, 455/506, 455/67.11, 455/60, 375/279, 375/283, 375/308, 375/329, 375/331
• US Class Current: 455/67.16
• CPC Class Codes: H04B 17/364 Delay profiles

Abstract

The present application describes a method and system for determining a time delay between a transmission and a reception of an RF signal in a noisy environment. The method comprises: transmitting the RF signal; shifting a phase of the RF signal after a first time period of the transmitting of the RF signal, starting at a known transition time; receiving a received RF signal comprising a received phase shift corresponding to the shifting of the phase of the transmitted RF signal, the received phase shift occurring at a receive transition time equivalent to a sum of the time delay and the known transition time; determining the receive transition time by detecting a time corresponding to the received phase shift; and calculating the time delay using the receive transition time and the known transition time.

Claims

1. A method for determining a time delay between a transmission and a reception of an RF signal in a noisy environment, the method comprising:

transmitting the RF signal;

shifting a phase of the RF signal after a first time period of the transmitting of the RF signal, starting at a known transition time;

receiving a received RF signal comprising a received phase shift corresponding to the shifting of the phase of the transmitted RF signal, the received phase shift occurring at a receive transition time equivalent to a sum of the time delay and the known transition time;

determining the receive transition time by detecting a time corresponding to the received phase shift; and

calculating the time delay using the receive transition time and the known transition time.

2. The method of claim 1, wherein the shifting comprises imposing a phase pattern on the RF signal, the phase pattern comprising a first time period during which the phase varies according to a first slope, a second time period during which the phase varies according to a second slope, and a transition from the first to the second slope, the known transition time defining one of a start of the transition, an end of the transition and a known point within the transition.

3. The method of claim 2, wherein the receiving comprises receiving the received RF signal comprising the received phase pattern, the received phase pattern comprising a receive transition between two slopes, the two slopes corresponding to the first slope and the second slope of the imposed phase pattern, the receive transition occurring at a receive transition time equivalent to the sum of the time delay and the known transition time.

4. The method of claim 1, wherein the determining comprises sampling the received RF signal to obtain the receive phase pattern and using the receive phase pattern to determine the receive transition time.

5. The method of claim 1, wherein the calculating comprises subtracting the known transition time from the receive transition time.

6. The method of claim 1, wherein the shifting comprises at least one of rising and decreasing the phase of the RF signal after the first time period of transmitting the RF signal, starting at the known transition time and during a second time period of transmitting the RF signal.

7. The method of claim 1, wherein the receiving of the received RF signal comprises receiving the received RF signal at one or more aerial, and wherein the determining of the receive transition time comprises combining received RF signals as received by each one of the one or more aerial.

8. A system for determining a time delay between a transmission and a reception of an RF signal in a noisy environment, the system comprising:

a signal transmitting device for transmitting the RF signal and for shifting a phase of the RF signal after a first time period of transmitting the RF signal, starting at a known transition time;

a signal receiving device for receiving a received RF signal comprising a received phase shift corresponding to the shifting of the phase of the transmitted RF signal, the received phase shift occurring at a receive transition time equivalent to a sum of the time delay and the known transition time; and

a processing device coupled to the signal receiving device, the processing device comprising a memory encoded with processing instructions for allowing the processing device to;

determine the receive transition time by detecting a time corresponding to the received phase shift; and

calculate the time delay using the receive transition time and the known transition time.

9. The system of claim 8, wherein the signal transmitting device comprises means for imposing a phase pattern on the RF signal, the phase pattern comprising a first time period during which the phase varies according to a first slope, a second time period during which the phase varies according to a second slope, and a transition from the first to the second slope, the known transition time defining one of a start of the transition, an end of the transition and a known point in the transition.

10. The system of claim 9, wherein the signal receiving device comprises a receiving device for receiving the received RF signal comprising the received phase pattern, the received phase pattern comprising a receive transition between two slopes, the two slopes corresponding to the first slope and the second slope of the imposed phase pattern, the receive transition occurring at a receive transition time equivalent to the sum of the time delay and the known transition time.

11. The system of claim 8, wherein the processing device comprises a sampling device for sampling the received RF signal to obtain the receive phase pattern and determine the receive transition time.

12. The system of claim 8, wherein the processing device comprises at least one of an adding and a subtracting circuit means for subtracting the known transition time from the receive transition time.

13. The system of claim 8, wherein the signal transmitting device comprises at least one of a signal modulator, an interference device and a signal phase shifting device.

14. The system of claim 8, wherein the signal transmitting device comprises means for at least one of rising and decreasing the phase of the RF signal after the first time period of transmitting the RF signal, starting at the known transition time and during a second time period of transmitting the RF signal.

15. The system of claim 8, wherein the signal receiving device comprises one or more aerials.

16. An apparatus for determining a time delay between a transmission and a reception of an RF signal in a noisy environment, the apparatus comprising:

a processing device;

a memory device accessible by the processing device; and

an application coupled to the processing device, the application configured for;

sending instructions to a transmitting device to start transmitting the RF signal;

sending instructions to a signal phase shifting device to start shifting a phase of the RF signal after a first time period of transmission of the RF signal, starting at a known transition time;

receiving from a receiving device, a received RF signal comprising a received phase shift corresponding to the shifting of the phase of the transmitted RF signal, the received phase shift occurring at a receive transition time equivalent to a sum of the time delay and the known transition time;

determining the receive transition time by detecting a time corresponding to the received phase shift; and

calculating the time delay using the receive transition time and the known transition time.