Device, method and system for estimating the termination to a wired transmission-line based on determination of characteristic impedance

• US 20060176044A1
• Filed: 03/29/2005
• Published: 08/10/2006
• Est. Priority Date: 01/23/2005
• Status: Active Grant

• Current Assignee: MOSAID Technologies Inc. (f/k/a Conversant Intellectual Property Management)
• Original Assignee: SercoNet Limited (Yehuda Binder, MBA)
• Inventors: Hazani, Ami, Binder, Yehuda
• Granted Patent: US 7,521,943 B2
• Time in Patent Office: Days
• US Class Current: 324/71.100
• CPC Class Codes: G01R 27/02 Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant by measuring phase angle only G01R25/00
• CPC Class Codes: G01R 27/04 in circuits having distributed constants , e.g. having very long conductors or involving high frequencies

Abstract

A system and method for measuring a characteristic impedance of a transmission-line comprises transmitting energy to the line, and shortly after measuring the voltage/current involved and thus measuring the equivalent impedance. The measured characteristic impedance may then be used in order to determine the termination value required to minimize reflections. In another embodiment, the proper termination is set or measured by adjusting the termination value to achieve maximum power dissipation in the terminating device. The equivalent characteristic impedance measurement may be used to count the number of metallic conductors connected to a single connection point. This abstract is not intended to limit or construe the scope of the claims.

Claims

1. A method for estimating the number of wire pairs connected to a single connection point, where all wire pairs have a similar nominal characteristic impedance Z0, the method comprising:

connecting a characteristic impedance measuring device to the connection point;

measuring the lumped impedance Z presented by the wire pairs at the connection point; and

calculating Z0/Z to provide an estimate of the number of wire pairs connected to the connection point.

2. The method according to claim 1, further comprising storing the measured impedance value or a representation of the estimate of the number of wire pairs.

3. The method according to claim 1, further comprising providing a visual indication of the measured impedance value or the estimate of the number of wire pairs.

4. The method according to claim 1, wherein the wire pairs are at least partially hidden in the wall of a building, the connection point is an outlet having a front faceplate, and connecting to the connection point comprises connecting to a connector on the front faceplate of the outlet.

5. The method according to claim 4, wherein the wire pairs form part of a telephone, AC power, or CATV wiring infrastructure, and the outlet is a telephone, AC power, or CATV outlet, respectively.

6. The method according to claim 5, wherein the infrastructure carries a signal in a first frequency band, and measuring the lumped impedance comprises transmitting energy to the connection point in a second frequency band distinct from the first frequency band.

7. The method according to claim 1, further comprising:

identifying a wiring end-point having a single connection wherein the connection point lumped impedance is Z0, and

connecting a termination to the connection point of the identified wiring end-point.

8. The method according to claim 1, wherein the wire pairs are at least partially hidden in the wall of a building, the connection point is an outlet, and connecting a characteristic impedance measuring device to the connection point comprises integrating the measuring device into the outlet.

9. The method according to claim 1, wherein a modem for communication is connected to the connection point, and said method further comprises a preliminary operation of disconnecting the modem from the connection point, and a subsequent operation of re-connecting the modem to the connection point.

10. The method according to claim 1, wherein measuring and calculating are initiated periodically, or upon application of an external signal, or upon a manual action, or upon powering up of the measuring device.

11. A device for estimating the number of wire pairs connected to a single connection point, where one or more wire pairs having a similar nominal characteristic impedance Z0 are all connected to the single connection point, said device comprising:

a port for connecting to the connection point,

a lumped impedance measuring unit coupled to said port for instantaneously measuring the connection point lumped impedance Z, and

a Z0/Z calculator coupled to the lump impedance measuring unit for estimating the connected wire pairs count to be Z0/Z.

12. The device according to claim 11, further comprising a memory coupled to said lump impedance measuring unit for storing the measured lumped impedance value or a representation of calculated number of wire-pairs.

13. The device according to claim 11, further comprising a visual indicator for displaying the measured lumped impedance value or the calculated number of wire-pairs.

14. The device according to claim 11, for use when the wire pairs are at least partially hidden in a wall of a building, the connection point is an outlet having a front faceplate, wherein said port comprises a connector that mates to a complementary connector on the front faceplate of the outlet.

15. The device according to claim 14, wherein the wire pairs form part of a telephone, AC power, or CATV wiring infrastructure, the outlet is a telephone, AC power, or CATV outlet, respectively, and said connector is a telephone, AC power, or CATV plug, respectively.

16. The device according to claim 15, wherein the infrastructure carries a signal in a first frequency band, and said lump impedance measuring unit comprises:

an energy transmitter coupled to said connector for transmitting energy to the connection-point said energy being carried in a second frequency band distinct from the first frequency band.

17. The device according to claim 11, further comprising:

means for identifying a wiring end-point having a single connection wherein the connection point lumped impedance is Z0, and

means for connecting a termination to the connection-point of an identified wiring end-point.

18. The device according to claim 11 for use when the wire pairs are at least partially hidden in the wall of a building, wherein the connection point is an outlet, and said device is at least in part integrated into the outlet.

19. The device according to claim 11 for use with a modem for communication over the wire pairs, wherein the device further comprises a selective connection unit for disconnecting the modem from the connection point and for re-connecting the modem to the connection point.

20. The device according to claim 11, further comprising a selector for operating said device either periodically, or upon application of an external signal, or upon a manual action, or upon powering up of the device.

21. A method for matching a termination to a wired transmission-line using a closed-control loop, the transmission-line being connected to carry a signal and having a nominal characteristic impedance, the method comprising:

connecting a termination having a controllable impedance value to the transmission-line;

measuring the power dissipated by termination; and

changing the termination impedance value to obtain a maximum power dissipation by the termination.

22. The method according to claim 21, further comprising storing a representation of the termination value.

23. The method according to claim 21, wherein said measuring comprises directly measuring at least one of the voltage across the termination and the current through the termination.

24. The method according to claim 21, wherein said measuring comprises indirectly measuring the dissipated power by measuring a physical phenomena affected by the dissipated power.

25. A device for matching a termination to a wired transmission line using a closed-control loop, the transmission-line being connected to carry a signal and having a nominal characteristic impedance, said device comprising:

a port for connecting to the wired transmission line,

a termination having a variable impedance value coupled to said port and having a control port,

means for measuring power dissipated coupled to said termination, and

control means coupled between said means for measuring and said control port for closed loop control operative for changing the impedance value of said termination to maximize power dissipated in said termination when power is supplied to the transmission line.

26. The device according to claim 25, further comprising a memory for storing a representation of the termination impedance value.

27. The device according to claim 25, wherein power dissipated in said termination is directly measured by measuring at least one of the voltages across said termination and the current through said termination.

28. The device according to claim 25, wherein power dissipated in said termination is indirectly measured by measuring a physical phenomena affected by the dissipated power.

29. A method for estimating an optimum impedance value for a termination to a wired transmission line having a lumped impedance Z comprising:

connecting a characteristic impedance measuring device to the wired transmission line,

instantaneously measuring the lumped impedance Z, and

estimating an optimum termination value based on the measured value Z.

30. The method according to claim 29, further comprising storing a representation of the measured lumped impedance value.

31. The method according to claim 29, wherein the estimated value is equal to the measured value Z.

32. The method according to claim 29, further comprising connecting a termination having the estimated value to the wired transmission line.

33. The method according to claim 29, wherein the wired transmission line comprises a wire pair at least partially hidden in the wall of a building and connected to an outlet having a front faceplate, and said connecting a characteristic impedance measuring device to the wired transmission line comprises connecting the device to a connector on the front faceplate of the outlet.

34. The method according to claim 33, wherein the wire pair is part of a telephone, AC power, or CATV wiring infrastructure, and said outlet is a telephone, AC power, or CATV outlet, respectively.

35. The method according to claim 34, wherein the infrastructure carries a signal in a first frequency band and said step of measuring comprises transmitting energy to the transmission line, the energy being in a second frequency band distinct from the first frequency band.

36. The method according to claim 29, wherein the wired transmission line comprises wire pairs at least partially hidden in the wall of a building, at least one of the wire pairs is connected to an outlet, and said method comprises the preliminary operation of integrating the measuring device into the outlet.

37. The method according to claim 29 for use with a modem for communication over the wired transmission line, wherein the wired transmission line comprises wire pairs, and said method further comprises:

initiating said measuring operation by disconnecting the modem from the wired transmission line; and

re-connecting the modem to the transmission-line after said measuring operation.

38. The method according to claim 29, wherein said measuring and estimating operations are initiated periodically, or upon application of an external signal, or upon a manual action, or upon powering up of the measuring device.

39. A device for estimating the termination to a wired transmission-line, the device comprising:

a port for connecting to the wired transmission-line,

impedance measuring unit coupled to said port for instantaneously measuring the lumped impedance Z of the transmission-line, and

means coupled to said impedance measuring unit for estimating the optimal termination value of the transmission-line based on the measured value Z.

40. The device according to claim 39, further comprising a memory coupled for storing the measured lumped impedance value.

41. The device according to claim 39, wherein the estimated value is equal to the measured value Z.

42. The device according to claim 39, further comprising means for connecting a termination having the estimated value to the wired transmission-line.

43. The device according to claim 39, wherein the wired transmission-line comprises a wire pair at least partially hidden in the wall of a building and connected to an outlet having a front faceplate, and said port comprises a connector for connecting to a further connector on the front faceplate of the outlet.

44. The device according to claim 43, wherein the wire pair is part of a telephone, AC power, or CATV wiring infrastructure, and the outlet is a telephone, AC power, or CATV outlet, respectively.

45. The device according to claim 44, wherein the infrastructure carries a signal in a first frequency band, and said impedance measuring unit comprises:

an energy transmitter coupled to said connector for transmitting energy to the wired transmission-line;

the energy being carried in a second frequency band distinct from the first frequency band.

46. The device according to claim 39, being integrated into an outlet.

47. The device according to claim 39, for use with a modem for communication over the wired transmission-line, wherein said device further comprises a switch for disconnecting the modem from the wired transmission-line, and for re-connecting the modem to the transmission-line.

48. The device according to claim 39, further comprising a selector for operating said device either periodically, or upon application of an external signal, or upon a manual action, or upon powering up of the device.