Apparatus and methods for network interface and spectrum management

• US 20050283815A1
• Filed: 06/01/2005
• Published: 12/22/2005
• Est. Priority Date: 06/01/2004
• Status: Active Grant

• Current Assignee: Time Warner Cable Enterprises LLC (Charter Communications Incorporated)
• Original Assignee: Time Warner Cable Inc. (Charter Communications Incorporated)
• Inventors: Brooks, Paul D., Romerein, Robert L.
• Granted Patent: US 8,095,098 B2
• Time in Patent Office: Days
• US Class Current: 725/126
• CPC Class Codes: H04H 20/78 CATV [Community Antenna Television] systems
• CPC Class Codes: H04N 21/6118 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 21/6168 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 7/102 Circuits therefor, e.g. noise reducers, equalisers, amplifiers H04N7/108 takes precedence
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications

Abstract

Apparatus and methods for the management of radio frequency spectrum within a network such as a CATV network. In one aspect of the invention, an improved signal reflector apparatus adapted for use in the network is disclosed, the reflector circuit being designed to strongly reflect signal frequencies at the lower end of the CATV reverse band, and/or above the higher end of the forward band, while simultaneously allowing the rest of the reverse band and the entire forward band to pass freely through the device. This selective filtering of the spectrum allows control signals generated within a premises or private network to be directed (by reflection) to other devices within that network. A blocking element (e.g., amplifier) may also be used to provide control of the transmission and attenuation profile of the reflector apparatus. The passage of power signals such as DC or low frequency AC is also optionally provided.

Claims

1. Radio frequency interface apparatus for use in a network, said apparatus being adapted to:

substantially attenuate first signals within a first frequency band and traveling in a first direction relative to said apparatus;

pass second signals within a second frequency band and traveling in said first direction; and

pass substantially all of third signals within both said first and second frequency bands and traveling in a second direction relative to said apparatus.

2. The apparatus of claim 1, further comprising an isolation amplifier adapted to selectively pass at least portions of said second and third signals.

3. The apparatus of claim 2, wherein said apparatus is adapted to pass an alternating current (AC) power signal in at least one of said first and second directions.

4. The apparatus of claim 3, wherein said power signal frequency is 120 Hz or less.

5. The apparatus of claim 4, further comprising a splitter circuit having at least two output ports, said splitter being electrically coupled to said apparatus and adapted to pass signals between said two output ports without significant signal loss.

6. The apparatus of claim 1, further comprising a plurality of capacitors arranged in a substantially series disposition so as to form a plurality of nodes therebetween, and a plurality of inductors electrically coupled to respective ones of said nodes.

7. The apparatus of claim 1, wherein said network comprises a CATV network, and said first band comprises frequencies below approximately 42 MHz.

8. The apparatus of claim 7, wherein said second band comprises frequencies above approximately 50 MHz.

9. The apparatus of claim 8, wherein said first direction comprises the upstream direction, and the second direction comprises the downstream direction, and said apparatus can pass at least two of said first, second and third signals simultaneously.

10. The apparatus of claim 1, wherein said apparatus is adapted to simultaneously pass a first portion of said third signals within said first frequency band with a first gain, and a second portion of said third signals within said second frequency band with a second gain.

11. The apparatus of claim 10, wherein said first gain is greater than said second gain, and both said first and second gains are greater than or equal to approximately 0 db.

12. A method for managing frequency spectrum within a radio frequency network having a demarcation point, comprising:

substantially attenuating first signals within a first frequency band and traveling in a first direction relative to said demarcation point;

passing second signals within a second frequency band and traveling in said first direction; and

passing third signals within both said first and second frequency bands and traveling in a second direction relative to said point.

13. The method of claim 12, wherein said radio frequency network comprises a public cable television network and a premises network, said demarcation point being disposed substantially at an interface between said public network and said premises network, and said act of substantially attenuating comprises substantially attenuating signals within said first band and traveling from said at least one private network to said public network to a value less than 0 db.

14. The method of claim 12, wherein said network comprises a CATV network, said act of first band comprises frequencies below approximately 42 MHz, and said second band comprises frequencies above approximately 50 MHz.

15. The reflector apparatus of claim 14, wherein said first direction comprises the upstream direction, and the second direction comprises the downstream direction.

16. Reflector apparatus for use in a network, said apparatus being adapted to:

substantially reflect first signals within a first frequency band and traveling in a first direction relative to said apparatus;

substantially pass second signals within a second frequency band and traveling in said first direction;

substantially pass third signals within said second frequency band and traveling in a second direction relative to said apparatus; and

substantially pass fourth signals in a third frequency band, said third band being lower in frequency than said first or second bands.

17. The reflector apparatus of claim 16, further comprising an isolation amplifier electrically coupled to said apparatus, said isolation amplifier being adapted to selectively control at least portions of a transmission spectrum of said apparatus, said spectrum providing for transmission in both of said first and second directions.

18. The reflector apparatus of claim 16, wherein said fourth signals comprise alternating current (AC) power signals, and said third band comprises frequencies at or below 120 Hz.

19. The reflector apparatus of claim 18, wherein said network comprises at least a subscriber-side network in signal communication with said reflector apparatus, and said reflector apparatus further comprises a splitter circuit adapted to provide a low impedance path between two nodes of said subscriber-side network.

20. The reflector apparatus of claim 16, wherein said apparatus comprises a plurality of capacitors arranged in a substantially series disposition so as to form a plurality of nodes therebetween, and a plurality of inductors electrically coupled to respective ones of said nodes.

21. The reflector apparatus of claim 16, wherein said network comprises a CATV network, and said first band comprises frequencies from approximately 5 MHz down to the top portion of said third band, and said second band comprises frequencies above approximately 7 MHz.

22. The reflector apparatus of claim 21, wherein said fourth signals comprise AC or DC power signals, and said top of said fourth band comprises a frequency of approximately 120 Hz.

23. The reflector apparatus of claim 16, wherein said apparatus is further adapted to pass signals above 50 MHz with a positive gain in said second direction, yet substantially attenuate signals above 50 MHz in said first direction.

24. Interface apparatus for use in a content-based network comprising:

an input port for coupling to a public portion of said network;

an output port for coupling to a subscriber portion of said network; and

a circuit including an isolation amplifier disposed electrically between said input and output ports;

wherein said circuit is adapted to;

(i) strongly reflect signals traveling from said output port toward said input port falling within a first frequency band;

(ii) pass substantial portions of signals traveling from said output port toward said input port falling within a second frequency band; and

(iii) attenuate signals traveling from said output port toward said input port falling within a third frequency band.

25. The apparatus of claim 24, wherein said second frequency band comprises a band encompassing DC through 120 Hz, and said first band is higher in frequency than 120 Hz at all frequencies therein.

26. The apparatus of claim 25, wherein said amplifier provides a transmission profile which provides a positive gain to signals falling within said third frequency band and traveling from said input port to said output port.

27. The apparatus of claim 25, wherein said amplifier provides a transmission profile which provides a substantially zero gain for at least some signals with frequencies falling below said third band, irrespective of their direction of travel.

28. Reflector circuit apparatus adapted for use in a content-based network, comprising:

a plurality of capacitive elements placed in series between a first terminal and a second terminal, said capacitive elements forming a plurality of individual nodes, each of said nodes being located electrically between two of said capacitive elements; and

a plurality of inductive elements, wherein a first end of each one of said plurality of inductive elements is electrically coupled to at least one of said nodes, and a second end of each of said plurality of inductive elements is electrically coupled, directly or indirectly, to ground potential.

29. The apparatus of claim 28, wherein said apparatus is adapted to provide power-passing capability, and further comprises at least one amplifier in signal communication with said reflector circuit, said amplifier providing for substantially gain-less transmission of signals in either direction through said circuit within a first frequency band, and transmission of signals with either a positive or negative gain, depending on direction of travel, within a second frequency band, said second frequency band having upper and lower frequencies which are higher than both the upper and lower frequencies of said first band.

30. The apparatus of claim 29, wherein said positive gain transmission is provided in a downstream direction of signal travel, and said negative gain transmission is provided in an upstream or reverse direction of signal travel.

31. The apparatus of claim 28, wherein at least a portion of said capacitive and inductive elements form a filter circuit selected from the group consisting of:

(i) a band-stop filter, and (ii) a low-pass filter; and

wherein the frequency band utilized by the apparatus is selected to be other than that of the pass-band of the content-based network.

32. In a cable network comprising a public portion and a subscriber portion, a method of doing business, comprising:

providing interface apparatus adapted to be installed at a demarcation point between said public portion and said subscriber portion, said circuit being adapted to selectively control the available frequency spectrum in both of upstream and downstream directions;

providing first services to said subscriber portion with said interface apparatus operating in a first mode;

selectively causing said interface apparatus-to operate in a second mode; and

providing second services to said subscriber portion with said interface apparatus operating in said second mode;

wherein said first and second services are not identical.

33. The method of claim 32, wherein said act of selectively causing comprises:

receiving indication that said subscriber is eligible for said second services; and

transmitting at least one signal to said interface apparatus to cause said operation in said second mode.

34. The method of claim 32, wherein said first mode comprises one providing a first available frequency spectrum, and said second mode comprises one providing a second available spectrum, said second spectrum being greater in size than said first spectrum.

35. A method for providing subscriber-side networking capability within a cable network having a public portion, subscriber-side network, and a demarcation point, comprising:

substantially reflecting first signals within a first frequency band and traveling towards said demarcation point within said subscriber-side network;

passing second signals within a second frequency band, said second signals also traveling towards said demarcation point within said subscriber-side network; and

passing third signals within both said first and second frequency bands, said third signals traveling away from said demarcation point within said subscriber-side network;

wherein said first signals are utilized at least in part to provide communications between individual nodes within said subscriber-side network.

36. Reflector circuit apparatus adapted for use in a content-based network, comprising:

a first plurality of capacitive elements placed in series between a first terminal and a second terminal, said first plurality of capacitive elements forming a plurality of individual nodes, each of said nodes being located electrically between two of said capacitive elements;

a first plurality of inductive elements disposed in electrical parallel with respective ones of said first plurality of capacitive elements; and

a second plurality of inductive elements, wherein a first end of each one of said second plurality of inductive elements is electrically coupled to at least one of said nodes, and a second end of each of said plurality of inductive elements is electrically coupled to at least one of a second plurality of capacitive elements, said at least one capacitive element also being electrically coupled to ground potential.