Line state detecting apparatus and transmitting apparatus and receiving apparatus of balanced transmission system

• US 20050232412A1
• Filed: 04/14/2005
• Published: 10/20/2005
• Est. Priority Date: 04/16/2004
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Yamashita, Akihiro, Ichihara, Fumio, Maki, Masahiro, Oishi, Mutsuhiko, Hanada, Tsunehiro, Wakisaka, Toshiyuki
• Granted Patent: US 8,139,759 B2
• Time in Patent Office: Days
• US Class Current: 379/414
• CPC Class Codes: H04B 2203/5425 improving S/N by matching impedance, noise reduction, gain control
• CPC Class Codes: H04B 2203/5445 Local network
• CPC Class Codes: H04B 2203/5483 using coupling circuits
• CPC Class Codes: H04B 2203/5491 using filtering and bypassing
• CPC Class Codes: H04B 3/30 Reducing interference caused by unbalanced currents in a normally balanced line
• CPC Class Codes: H04B 3/56 Circuits for coupling, blocking, or by-passing of signals

Abstract

A line state detecting apparatus provided in a balanced transmission system includes, in transmission lines comprising a pair of conductors W1, W2 connected to a transmitting portion 13, current transformers T11, T12 primary sides of which are inserted to respectives thereof in series therewith and secondary sides of which are connected in series to cancel currents or voltages of the two transformer by each other, and a detecting portion 11 for detecting currents or voltages on secondary sides of the current transformers T11, T12. By an output of the detecting portion 11, a difference of currents or voltages of the conductors W1, W2 of the transmission lines is provided and an unbalance component between the conductors W1, W2 is detected.

Claims

1. A line state detecting apparatus for detecting a state of a transmission line in a balanced transmission system for transmitting a data by using a pair of conductors, said line state detecting apparatus comprising:

an unbalance component detector for directly detecting an unbalance component between the pair of conductors.

2. The line state detecting apparatus according to claim 1, wherein the pair of conductors are power lines.

3. The line state detecting apparatus according to claim 1, wherein the unbalance component detector comprises:

current transformers primary windings of which are inserted to respectives of the pair of conductors in series therewith and secondary windings of which are connected in series and

a detector for detecting currents or voltages of the secondary windings connected in series,

wherein the secondary windings of the current transformers are connected to cancel the currents or the voltages of the two transformers by each other.

4. The line state detecting apparatus according to claim 1, wherein the unbalance component detector comprises:

a common mode coil a first and a second winding of which are inserted to respectives of the pair of conductors in series therewith and including a third winding for detecting a common mode and

a detector for detecting a voltage or a current induced in the third winding.

6. The line state detecting apparatus according to claim 2, wherein the unbalance component detector comprises an impedance provided between the pair of conductors and a detector for detecting a current or a voltage between a middle point of the impedance and the ground.

7. The line state detecting apparatus according to claim 6, further comprising:

a detection transformer a primary winding of which is inserted between the middle point of the impedance and the ground;

wherein the detector detects a current or a voltage of a second winding of the detection transformer.

8. The line state detecting apparatus according to claim 6, wherein the impedance serves also as a terminator of the transmission lines.

9. The line state detecting apparatus according to claim 1, wherein the transmission lines are connected to a transmitting apparatus or a receiving apparatus by way of a transmission transformer;

and

wherein the unbalance component detector comprises an impedance connected to a middle point of a winding on a side of the transmission lines of the transmission transformer and a voltage detector for detecting a voltage between the impedance and the ground.

10. The line state detecting apparatus according to claim 1, wherein the transmission lines are connected to a transmitting apparatus or a receiving apparatus by way of a transmission transformer;

and

wherein the unbalance component detector comprises a detector for detecting a current or a voltage between a middle point of a winding on a side of the transmission lines of the transmission transformer and the ground.

11. The line state detecting apparatus according to claim 9, further comprising:

a detection transformer a primary winding of which is inserted between the middle point of the winding on the side of the transmission lines of the transmission transformer and the ground;

wherein the detector detects a current or a voltage of the secondary winding of the detection transformer.

12. The line state detecting apparatus according to claim 10, further comprising:

a detection transformer a primary winding of which is inserted between the middle point of the winding on the side of the transmission lines of the transmission transformer and the ground;

wherein the detector detects a current or a voltage of the secondary winding of the detection transformer.

13. The line state detecting apparatus according to claim 1, wherein the unbalance component detector detects an amplitude and a direction of the unbalance component between the pair of conductors.

14. The line state detecting apparatus according to claim 13, wherein the unbalance component detector compares phases of a transmission signal outputted to the conductors and a difference of a current or a voltage in a forward line and a rearward line of the conductors.

15. The line state detecting apparatus according to claim 13, wherein the unbalance component detector calculates a product of the transmission signal outputted to the conductor by the difference of the current or the voltage in the forward line and the rearward line of the conductors.

16. The line state detecting apparatus according to claim 13, further comprising:

a phase shifter for controlling a phase of at least one of a transmission signal outputted to the conductors and a difference of a current or a voltage of in a forward line and a rearward line of the conductors.

17. A transmitting apparatus which is a transmitting apparatus used in a balanced transmission system for transmitting a data by using a pair of conductors, said transmitting apparatus comprising:

a transmitting side line state detecting apparatus comprising the line state detecting apparatus according to claim 1.

18. The transmitting apparatus according to claim 17, further comprising:

a transmission signal controller for controlling a transmission signal outputted to the conductors based on an output of the transmission side line state detecting apparatus.

19. A receiving apparatus which is a receiving apparatus used in a balanced transmission system for transmitting a data by using a pair of conductors, said receiving apparatus comprising:

a receiving side line state detecting apparatus comprising the line state detecting apparatus according to claim 1;

and

a line state output unit for outputting a state detecting signal indicating a line state of the transmission lines based on an output of the receiving side line state detecting apparatus.

20. A transmitting apparatus which is a transmitting apparatus used in a balanced transmission system for transmitting a data by using a pair of conductors, said transmitting apparatus comprising:

a transmission signal controller for controlling a transmission signal outputted to the conductors based on the state detecting signal outputted from the receiving apparatus according to claim 19.

21. A balanced transmission system which is a balanced transmission system for transmitting a data by using a pair of conductors, said balanced transmission system comprising:

a transmitting apparatus comprising a transmitting side line state detecting apparatus comprising the line state detecting apparatus according to claim 1 and a transmission signal controller for controlling a transmission signal outputted to the conductors; and

a receiving apparatus comprising a receiving side line state detecting apparatus comprising the line state detecting apparatus according to claim 1 and a line state output unit for outputting a state detecting signal indicating a line state of the transmission lines based on an output of the receiving side line state detecting apparatus;

wherein the transmission signal controller controls the transmission signal outputted to the conductors based on an output of the transmitting side line state detecting apparatus and the state detecting signal outputted from the receiving apparatus.

5. A power source connecting apparatus used for a line state detecting apparatus for detecting a state of a transmission line in a balanced transmission system for transmitting a data by using a pair of conductors and comprising an unbalance component detector for directly detecting an unbalance component between the pair of conductors, said power source connecting apparatus comprising:

a common mode coil a first and a second winding of which are inserted to respectives of the pair of conductors in series therewith and including a third winding for detecting a common mode as the unbalance component detector.

22. A line state detecting apparatus which is a line state detecting apparatus for detecting a state of a transmission line in a balanced transmission system for transmitting a data by using a pair of conductors, said line state detecting apparatus comprising:

an electrical component detector for detecting currents flowing in the conductors or voltages of the conductors or both thereof for the respective conductors; and

an unbalance component calculator for calculating a difference of the currents of the respective conductors or a difference of the voltages for the respective conductors or both thereof detected by the electrical component detector.

23. The line detecting apparatus according to claim 22, wherein the pair of conductors are power lines.

24. The line state detecting apparatus according to claim 22, wherein the electrical component detector includes a current detector for detecting the currents flowing in the conductors for the respective conductors.

25. The line state detecting apparatus according to claim 24, wherein the current detector includes impedances inserted to respectives of the pair of conductors in series therewith and a voltage detector for detecting voltages across both ends of the impedances.

26. The line detecting apparatus according to claim 24, wherein the current detector includes current transformers primary windings of which are inserted to respectives of the pair of conductors in series therewith and a current detector for detecting currents or voltages of secondary windings of the current transformers.

27. The line state detecting apparatus according to claim 22, wherein the electrical component detector includes a voltage detector for detecting voltages of the conductors relative to a predetermined reference potential for the respective conductors.

28. The line state detecting apparatus according to claim 22, wherein the unbalance component calculator calculates at least one of a difference of currents of a forward line and a rearward line of the respective conductors and a common mode amount of voltages of the respective conductors as the difference.

29. The line state detecting apparatus according to claim 22, wherein the unbalance component calculator calculates an amplitude and a direction of an unbalance component between the pair of conductors based on the difference.

30. The line state detecting apparatus according to claim 29, wherein the unbalance component calculator compares phases of a transmission signal outputted to the conductors or the currents or the voltages of the conductors and the difference of the currents of the forward line and the rearward line of the conductors or the amount of the common mode voltage.

31. The line state detecting apparatus according to claim 29, wherein the unbalance component calculator calculates a product of the transmission signal outputted to the conductors or the currents or the voltages of the conductors by the difference of the currents of the forward line and the rearward line of the conductor or the amount of the common mode voltage.

32. The line state detecting apparatus according to 30, further comprising:

a phase shifter for controlling at least one of the phases of the transmission signal outputted to the conductors or the currents or the voltages of the conductors and the difference of the currents of the forward line and the rearward line of the conductors or the amount of the common mode voltage.

33. The line state detecting apparatus according to 31, further comprising:

a phase shifter for controlling at least one of the phases of the transmission signal outputted to the conductors or the currents or the voltages of the conductors and the difference of the currents of the forward line and the rearward line of the conductors or the amount of the common mode voltage.

34. A transmitting apparatus which is a transmitting apparatus used in a balanced transmission system for transmitting a data by using a pair of conductors, said transmitter comprising:

a transmitting side line state detecting apparatus comprising the line state detecting apparatus according to claim 22.

35. The transmitting apparatus according to claim 34, further comprising:

a transmission signal controller for controlling a transmission signal outputted to the conductors based on an output of the transmitting side line state detecting apparatus.

36. A receiving apparatus which is a receiving apparatus used in a balanced transmission system for transmitting a data by using a pair of conductors, said receiving apparatus comprising:

a receiving side line state detecting apparatus comprising the line state detecting apparatus according to claim 22;

and

a line state output unit for outputting a state detecting signal indicating a line state of the transmission line based on an output of the receiving side line state detecting apparatus.

37. A transmitting apparatus used in a balanced transmission system for transmitting a data by using a pair of conductors, said transmitter comprising:

a transmission signal controller for controlling a transmission signal outputted to the conductors based on the state detecting signal outputted from the receiving apparatus according to claim 36.

38. A balanced transmission system which is a balanced transmission system for transmitting a data by using a pair of conductors, said balanced transmission system comprising:

a transmitting apparatus comprising a transmitting side line state detecting apparatus comprising the line state detecting apparatus according to claim 22 and a transmission signal controller for controlling a transmission signal outputted to the conductors; and

a receiving apparatus comprising a receiving side line state detecting apparatus comprising the line state detecting apparatus according to claim 22 and a line state output unit for outputting a state detecting signal indicating a line state of the transmission line based on an output of the receiving side line state detecting apparatus;

wherein the transmission signal controller controls the transmission signal outputted to the conductors based on an output of the transmitting side line state detecting apparatus and the state detecting signal outputted from the receiving apapratus.