MXPA00007057A - Catv power inserter - Google Patents

Abstract

A CATV power inserter is presented allowing multiple powersourcing configurations while providing isolation between the RF signal and alternating current insertion ports. The power inserter achieves the variety of configurations by using a four point terminal block having uniform dimensions allowing simple connecting bars and fusing or current limiting options to be interchanged thereby increasing economy and performance.

Description

CATV ENERGY INSERTER BACKGROUND OF THE INVENTION Field of the Invention This invention relates in general to the distribution components of a cable television communication system. More particularly, the invention relates to an energy inserter having double energy supply inputs or gates, which can be internally configured to the source energy directionally, or to the use of independent main power supplies for dedicated addresses in a CATV distribution system.

Description of the prior art Cable television services (CATV) are provided to customers through a transmission network that typically includes a trunk system that transports the plurality of CATV services from a cable RF section to smaller branches and then over branches of individual subscribers. The transmission medium for the subscriber branch and branches is usually coaxial cable. To provide transmission of CATV services, the transmission network includes cable branches, cable splitters, line amplifiers and other miscellaneous equipment to distribute CATV services. A typical CATV cable plant is designed with unit gain from the RF section to each subscriber terminal. Signal losses and gains along the trunk line, branch lines, and subscriber branches are annotated and adjusted to maintain unit gain throughout. However, many of the aforementioned devices that distribute cable services overload the system. As the CATV signal proceeds throughout the entire distribution system, attenuation of the coaxial cable and loss of insertion of the passive devices reduce the signal to less than one unit, which requires periodic amplification. In-line amplifiers are installed and adjusted accordingly to maintain unity gain.

The line amplifiers are usually suspended by the coaxial cable support line carrying the signal, and are energized from the coaxial cable carrying the signal. The usual method of distributing the mainline power supply to each in-line amplifier is by printing or inserting the alternating current over the coaxial cable via a power CA.TV. An energy inserter consists of a low pass filter designated for 60 cycles, 60 Vac and a band rejection filter for the RF signal components present on the coaxial cable. The power inserter is housed in an RFI-proof housing or housing and environmental conditions, and is also suspended on the rope end. In a line amplifier, the filters separate the CATV RF signal from the 60 Vac printed. The RF signal is amplified with the ac component that provides the power source. The energy is usually supplied to an energy inserter by a ferroresonant transformer located on a nearby telephone pole. The main side of the ferroresonant transformer is connected to a single phase power supply from the local installation. Ferroresonant transformers provide insulation, regulation and, if necessary, reduction from the mainline power supply. The power inserter can provide power for several line amplifiers. In Figure 1 a simplified branch 15 of a CATV distribution system is shown. The power inserter 17 of the prior art is shown serving four line amplifiers 19 on either side of the power inserter 17. A ferroresonant transformer 21 is shown providing energy to the power inserter 17. The flow of energy and signals are bidirectional within the coaxial cable 23. A schematic for the prior art power inserter 17 is shown in Figure 2. The power inserter 17 has a simple energy linker 25, and first 27 and second 29 RF conjunctor or accesses. The direct alternating current 31 is filtered using a first two-pole low-pass filter (second order) comprised of a first inductor 33 coupled to a first 35 and a second 37 parallel capacitors.

The current flow for both directions of the coaxial cable is limited to the first 39 and the second 41 fuses to their respective first 27 and second 29 RF sets. The energy insertion can be directional depending on whether one or both fuses are installed. The output from the first fuse 39 is filtered in low pass through a second low-pass filter 2-pole, and coupled to the signal conductor of the first RF-junction 27. The output from the second fuse 31 is filtered in step low through a third low-pass filter, two-pole and coupled to the signal conductor of the second RF-connector 29. To allow the RF signal to pass freely between the first 27 and the second RF-sets, a sixth capacitor 51 forms a high pass filter between the RF terminals that block the low frequency current, thereby giving direction to the energy flow. A variation of the single-source power inserter 19 is shown in Figures 3 and 4. An inserter 53 of the direct or double alternating current source is shown having two isolated ac terminals (depending on the configuration of a bridge). of internal connection 54) each providing power to a dedicated RF terminal. However, the prior art dual-power power inserter 53 has limitations when the power inserter 53 is configured with respect to the insulation between the RF terminals and the power accesses. In order to increase the number of available source options in a cable television power inserter, it is desirable to have a low cost device that can provide insertion or distribution of directional energy, common or isolated.

BRIEF DESCRIPTION OF THE INVENTION A CATV power inserter is presented, which allows a plurality of power source options while providing superior isolation between the RF signal and the power supply insertion points. The energy inserter achieves the variety of configurations through the use of a four-point terminal block that has compatible, uniform dimensions, which allow simple connection bars, fusion and current limiting options to be quickly exchanged, with which the economy increases. Accordingly, an object of the present invention is to provide a CATV power inserter having dual power supply accesses. A further objective of the present invention is to provide an energy inserter that allows multiple configurations for single or double power supplies and the ability to easily add current limiting functions. Other objects and advantages of the energy inserter will become apparent to those skilled in the art after reading the detailed description of the preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram of a CATV distribution branch of the prior art with a simple ac / dc access power inserter and line amplifiers.

Figure 2 is a prior art scheme of the simple ac / dc access power inserter. Figure 3 is a block diagram of a CATV distribution branch of the prior art, with a dual ac / dc access power inserter and in-line amplifiers. Figure 4 is a schematic prior art diagram of the dual ac / dc access power inserter. Figure 5 is a CATV power inserter embodying the present invention. Figure 6 is an alternative configuration of the present invention, having a common, high current ac / dc access. Figure 7 is an alternative configuration of the present invention having a simple, directional ac / dc access. Figure 8 is an alternative configuration of the present invention having a simple, directional ac / dc access. Figure 9 is an alternative configuration of the present invention having isolated, double directional ac / dc accesses.

Figure 10 is an alternative configuration of the present invention having directional, isolated, double ac / dc accesses with current limitation. Figure 11 is an alternative configuration. of the present invention having isolated, double directional ac / dc accesses with the set of current active overload suppression circuits.

DESCRIPTION OF THE PREFERRED MODALITIES The preferred embodiment will be described with reference to the figures of the drawings where similar numbers represent similar elements throughout the description. With reference to Figure 5, an energy inserter 55 exemplifying the present invention is shown. The power inserter 55 includes four external connections; first 57 and second 59 ac / dc sets or accesses and first 61 and second 63 sets or accesses of RF signals. The individual components of the power inserter 55 are assembled on a printed circuit board (PCB) which is housed in a cast, lightweight die-cast aluminum alloy housing with a rotating face plate that provides mounting cape or pedestal and the protection or shielding of RFI. The power inserter 55 includes dual ac / dc access, distribution, and coupling to the RF signal setters. The first ac / dc 57 junctor is derived with a first capacitor Cl that forms the node a. The node a is also coupled to a first terminal 67 of a configurable terminal block 69. The second ac / dc conjunctor is derived with a second capacitor C2 that forms the node b. The node b is coupled to a second terminal 73 of the configurable terminal block 69. The configurable terminal block 69 includes third 75 and fourth 77 terminals forming the nodes c and d respectively. The node c is coupled to a first low-pass, four-pole filter 79 that includes third C3 and fourth C4 capacitors and first Ll and second L2 inductors. The second inductor L2 is coupled to the signal-carrying conductor of the first RF conjunctor 61 that forms the node e. The node d is coupled to a second 4-pole low pass filter 89 that includes fifth C5 and sixth C6 capacitors and third L3 and fourth L4 inductors. The fourth inductor L4 is coupled to the conductor carrying signals of the second RF linker 63 forming the node f. Coupled between the conductors carrying signals from the first 61 and the second 63 RF sets (Nodes e and f) is a seventh capacitor C7 to pass high frequencies. The values of the individual components for the preferred embodiment are shown in Table 1.

TABLE 1 A discussion of passive filters using inductors and capacitors of various orders (poles) is beyond the scope of this specification and is well understood by those skilled in the art of electronics. With reference to the schematic representation shown in Figure 5, it can be observed by the coupling of individual connection bars 101 between the terminals 67, 73, 75 and 77 of the configurable terminal block 69, various combinations of the power supply dictating the direction , can easily be achieved by the present invention. The energy can be directed through the various nodes (nodes af) to any signal junctor 61, 63. As will be realized by a person skilled in this art, the present invention can also act as a source of energy or bifurcation since The current flow is bidirectional. With reference to Figures 6, 7 and 8, configurations of the configurable terminal block 69 are shown which allows either the first 57 or the second 59 ac / dc assemblies to apply energy to the power inserter 55, in the directions dedicated in the physical position where the power inserter 55 is placed on the coaxial cable 23. Figures 7 and 8 show configurations where the energy insertion is directional for the configuration of the terminal block 69 and if power is applied to the first 57 or the second 59 ac / dc assemblies. The uncoupled ac / dc junction is open circuit. Figure 9 shows the connecting rod 101 positioned to allow current to flow from the first ac / dc conjuctor 57 to the first RF accessor 61. Figure 8 shows the connecting rod 101 positioned to allow current to flow from the second ac / dc junctor 59 to the second RF accessor 63. The configuration shown in Figure 9 allows independent mainline power, be applied in dedicated, separate cable directions, at the site of the power inserter 55. In this configuration, two connection bars 101 are used, isolating the first 57 and second 59 ac / dc assemblies from each other, and allowing separate, directional, energy insertion paths with different current requirements through their respective sets. of RF.

Figures 10 and 11 show the optional circuit boards 107, 109 having four terminals aligned to mate with the configurable terminal block 69. Figure 10 shows a simple melting arrangement that includes first Fl and second F2 fuses that provide protection to the wiring of the power supply of the main line for the first 57 and the second 59 ac / dc assemblies. The first fuse Fl couples the first 67 and fourth 77 terminals of the configurable terminal block 69 (not shown). The second fuse F2 couples the second 73 and the third 75 terminals of the configurable terminal block 69 (not shown). As can be appreciated by a person skilled in the art, the values of the fuse may vary in consideration of the power capacity of the main line, upstream, and the capacity of the cable. The present invention can be configured for various numbers of in-line amplifiers located on either side of the energy insertion point. A similar function is shown in Figure 11 with the suppression of momentary, active, double overloads. The first current limiting circuit Illa couples the first 67 and fourth 77 terminals of the configurable terminal block 69 (not shown). The second current limiting circuit 111b couples the second 73 and third 75 terminals of the configurable terminal block 69 (not shown). In this configuration, periodic verification of active current is used for each energy insertion path. This configuration limits the range of the current draw to a predetermined value. While the present invention has been described in terms of the preferred embodiment, other variations that are within the scope of the invention will be apparent to those skilled in the art, as described in the following claims.

Claims (13)

1. A passive component, configurable by the user to supply an alternating or direct current on or from a coaxial cable having first and second signal accesses, and first and second current accesses; the component has: a terminal block configured having four terminals; the first current access is coupled to a first terminal of the configurable terminal block forming a node a; the second current access is coupled to a second terminal of the terminal block forming a node b; a third terminal of the configurable terminal block defining a node c, the first signal access defines a node e; and a terminal letter of the configurable terminal block defines a node d, the second signal access defines a node f; the component is characterized by: a first low frequency step circuit, coupled between the nodes e and e, a second low frequency step circuit coupled between the nodes d and f; and a high-frequency step circuit coupled to the first and second signal accesses between the nodes e and f; whereby each terminal of the configurable terminal block is selectively connectable to the other terminals.

2. The passive component according to claim 1, further characterized in that the first and second low frequency pass circuits are low pass filters having predetermined responses, determined by various orders.

3. The passive component according to claim 1, further characterized in that the high-frequency step circuit is a high-pass filter having a predetermined response, determined by various orders.

4. The passive component according to claim 1, further characterized in that the insertion or removal of energy can be performed in the current accesses.

5. The passive component according to claim 1, further characterized in that at least one connecting rod is coupled to at least two of the terminals of the configurable terminal block, whereby the terminals of the configurable terminal block are selectively configured to allow the plurality of component configurations.

6. The passive component according to claim 5, further characterized in that the connecting rod is coupled to the first, second, third and fourth terminals of the configurable biocable terminal.

7. The passive component according to claim 5, further characterized in that the connecting rod is coupled to the second and fourth terminals of the configurable terminal block, and a second connection bar is coupled to the first and third terminals of the configurable terminal block.

8. The passive component according to claim 5, further characterized in that the connecting rod is coupled to the first and fourth terminals of the configurable terminal block, and a second connection bar is coupled to the third and fourth terminals of the configurable terminal block.

9. The passive component according to claim 5, further characterized in that the connecting rod is coupled to the first and third terminals of the configurable terminal block.

10. The passive component according to claim 5, further characterized in that the connecting rod is coupled to the second and fourth terminals of the configurable terminal block.

11. The passive component according to claim 5, further characterized in that the connecting rod is coupled to the first and third terminals of the configurable terminal block and a second connection bar is coupled to the second and fourth terminals of the configurable terminal block.

12. The passive component according to claim 1, further characterized by: a fuse board having first and second fuses and four terminals; the first fuse is coupled between a first and a second terminal of the terminals of the fuse board, and the second fuse is coupled between a third and a fourth terminal of the terminals of the fuse board; the terminals of the fuse board are aligned with the configurable terminal block, allowing precise coupling, whereby the first fuse is coupled to the first and third terminals of the configurable terminal block, and the second fuse is coupled to the second and fourth terminals of the configurable terminal block.

13. The passive component according to claim 1, further characterized by: a momentary overload suppression board, having first and second circuits for suppression of momentary overloads and four terminals; the first momentary surge suppression circuit is coupled between a first and a second terminal of the suppression board terminals and the second circuit of suppression of momentary overloads is coupled between a third and a fourth terminal of the suppression board terminals; the terminals of the suppression board align with the configurable terminal block, allowing precise coupling whereby the first momentary overload suppression circuit is coupled to the first and third terminals of the configurable terminal block, and the second circuit of suppression of momentary overloads are coupled to the second and fourth terminals of the configurable terminal block.