Method and apparatus for a self-terminating signal path

• US 8,082,570 B2
• Filed: 12/02/2009
• Issued: 12/20/2011
• Est. Priority Date: 03/30/2009
• Status: Active Grant

• Current Assignee: PPC Broadband Incorporated (Belden Inc.)
• Original Assignee: John Mezzalingua Associates Incorporated
• Inventors: Olson, Thomas A., Kelma, David, Lai, Joseph, Alkan, Erdogan, Jackson, David H., Palinkas, Raymond W., Shafer, Steven K.
• Primary Examiner(s): CRAWFORD, JASON
• Application Number:
  US12/629,255
• Publication Number:
  US 20100244980A1
• Time in Patent Office: 748 Days
• Field of Search: 725125-127, 326/30
• US Class Current: 725/125
• CPC Class Codes: H04N 7/104 Switchers or splitters

Abstract

Presented are method and apparatus embodiments to terminate an interruptible signal path when the interruptible signal path is unterminated. The apparatus can comprise a signal path from a supplier-side port thru a user-side port, a signal source arranged to provide a signal to the conductor; and a signal circuit arranged in the interruptible signal path. The apparatus can determine when the signal path is unterminated and, in that case, interrupt and terminate the signal path by putting a signal switching device in the appropriate state and/or sending signals from the signal path to a prescribed signal level connection point. When a user device is not connected or connected improperly, or the signals through the signal path are otherwise unterminated, the interruptible signal path can be interrupted and terminated. The method and apparatus embodiments can be used in various combinations with multiple signal paths having multiple signal branches.

Claims

1. An apparatus for reducing noise ingress, said apparatus comprising:

at least one interruptible signal path extending from a supplier-side port through a user-side port, each of said interruptible signal paths comprising a conductor and a prescribed signal level connection point;

a signal source coupled to at least one of said interruptible signal paths, said signal source arranged to provide a signal to said conductor; and

at least one signal circuit, each signal circuit being arranged in one of said interruptible signal paths, each signal circuit configured to determine, based on a value of said signal, when said interruptible signal path is unterminated, and to interrupt and terminate said interruptible signal path to said prescribed signal level connection point when said interruptible signal path is determined by said signal circuit to be unterminated, wherein each of said signal circuits determines whether at least one of said interruptible signal paths is unterminated by determining an impedance on said conductor, and comparing said impedance to a reference value.

2. The apparatus of claim 1, wherein each interruptible signal path comprises multiple branches, and said signal circuit is positioned on any of said multiple branches.

3. The apparatus of claim 2, wherein each of said signal circuits further comprises:

a termination circuit positioned on any of said multiple branches; and

a sensor circuit positioned on any of said multiple branches.

4. The apparatus of claim 2, wherein each of said signal circuits further comprises:

a termination circuit positioned on a first branch of a first interruptible signal path; and

a sensor circuit positioned on a second branch of said first interruptible signal path, wherein said sensor circuit is in signal communication with said termination circuit.

5. The apparatus of claim 1, wherein each signal circuit comprises a signal switching device having at least a first state and a second state, wherein said first state enables an alternating electrical current signal to travel said interruptible signal paths through said user-side ports and said second state terminates said interruptible signal paths from said conductor to said prescribed signal level termination over a terminating signal path having a terminating impedance.

6. The apparatus of claim 5, wherein said state of said signal switching device is determined by a control signal received from a signal comparison device.

7. The apparatus of claim 1, wherein each of said signal circuits determines whether at least one of said interruptible signal paths is terminated by comparing a signal characteristic representative of said signal on said interruptible signal path with a reference value.

8. The apparatus of claim 1, wherein each of said interruptible signal paths is terminated to said prescribed signal level connection point over a terminating signal path having a resistance to match a characteristic impedance of said interruptible signal paths.

9. A signal splitter for reducing noise ingress, said signal splitter comprising:

an interruptible signal path extending from a supplier-side port through an output of a user-side port, the interruptible signal path comprising one or more signal branches;

a signal detector to detect a signal level on the interruptible signal path at the user-side port;

a signal switching device arranged on a first branch of the one or more of signal branches, the signal switching device to selectively interrupt the first branch of the interruptible

signal path when the interruptible signal path coupled to the user-side port is unterminated, wherein said signal switching device operates in said first state to maintain the interruptible signal path when a measured voltage at a first input of a signal comparison device connected through a prescribed resistance to the interruptible signal path is below a reference voltage at a second input of the signal comparison device, wherein the signal comparison device is connected in parallel with the interruptible signal path; and

a coupler circuit to perform AC coupling between the signal detector and the signal switching device, wherein the signal detector, the coupler circuit, and the signal switching circuit connect in series to at least the first branch of the one or more signal branches in the interruptible signal path.

10. The signal splitter of claim 9, wherein the signal switching device is to operate in a second state to interrupt the first branch of the interruptible signal path when the signal level is greater than a threshold, the second state to connect the interrupted interruptible signal path to a prescribed reference level connection point, the signal switching device to receive a control signal from the signal detector to determine in which of the first state and the second state to operate.

11. The signal splitter of claim 10, wherein the signal switching device is connected to receive a control signal from the signal comparison device in the signal detector, the signal comparison device to compare at least one signal characteristic of a signal at the signal comparison device, said signal characteristic being indicative of whether the interruptible signal path coupled to the user-side port is terminated.

12. The signal splitter of claim 10, wherein the signal switching device is in the first state when a user device draws a current greater than a reference current value

13. A method of terminating a port to prevent noise ingress comprising the steps:

applying a current to a conductor of at least one interruptible signal path through at least one user-side port, each of said interruptible signal paths including one or more signal branches;

determining whether each of said interruptible signal paths is terminated on a user side of a reference point; and

interrupting and terminating each of said interruptible signal paths at a termination point when said interruptible signal paths are unterminated on the user side of a reference point in a predetermined acceptable arrangement, wherein at least one termination circuit is configured to interrupt and terminate one or more of said interruptible signal paths at one or more of said signal branches when a user device draws a current greater than a reference current value.

14. The method of claim 13, wherein said reference point is a termination circuit.

15. The method of claim 13, wherein determining whether said interruptible signal path is unterminated is accomplished automatically by at least one sensor circuit positioned in at least one of said signal branches.

16. The method of claim 15, wherein each of said sensor circuits is configured to compare at least one signal characteristic representative of a signal in said interruptible signal path with at least one reference value.

17. The method of claim 15, wherein each of said sensor circuits comprises a signal comparison device for determining whether a user device draws a current sufficient to cause a voltage drop that lowers a measured voltage at said signal comparison device below a reference voltage at said signal comparison device.

18. The method of claim 13, wherein determining whether said interruptible signal path is unterminated at one or more of said signal branches is done by comparing at least one signal characteristic representative of a signal in said interruptible signal path with at least one reference value.

19. The method of claim 13, wherein at least one termination circuit is configured to interrupt and terminate one or more of said interruptible signal paths at one or more of said signal branches when a user device draws a current sufficient to cause a voltage drop and lower a measured voltage at a signal comparison device below a threshold voltage at said signal comparison device, wherein said signal comparison device is connected in parallel to said interruptible signal path.