WO2008002056A1

WO2008002056A1 - Trunk bridge amplifier using multi channel diplexer

Info

Publication number: WO2008002056A1
Application number: PCT/KR2007/003087
Authority: WO
Inventors: Jun Ho Kim; Jung Beom Park; Moon Sung Jung
Original assignee: Hannet Telecom Co., Ltd.
Priority date: 2006-06-27
Filing date: 2007-06-26
Publication date: 2008-01-03
Also published as: KR100678662B1

Abstract

A trunk bridge amplifier according to the present invention does not require that a structure in which an existing trunk bridge amplifier transmits and receives network signals only via an upstream transmission band and a downstream transmission band be changed, thereby maintaining compatibility with existing trunk bridge amplifiers, and employing a new frequency band for the transmission of network signals through an existing wired broadcasting network. For this, the present invention provides a trunk bridge amplifier, the trunk bridge amplifier having a plurality of diplexers each for performing division into at least two frequency bands, and at least one amplifier for amplifying the resulting frequency bands, including a bidirectional amplifier, the diplexer performs division into an upstream frequency band, a downstream frequency band, and a first frequency band, and includes a high frequency band connection terminal for separately performing division on the first frequency band, and the first frequency band is provided to the bidirectional amplifier, and an input/output (I/O) terminal of the bidi-rectional amplifier is connected to the high frequency band connection terminal of the diplexer and is then driven, so that a structure of a trunk bridge amplifier for the upstream frequency band and the downstream frequency band is not changed.

Description

TRUNK BRIDGE AMPLIFIER USING MULTICHANNEL

DIPLEXER

Technical Field

[1] The present invention relates to a trunk bridge amplifier that uses a multichannel diplexer and, more particularly, to a trunk bridge amplifier that can cover at least three transmission bands transmitted between an optical network device and subscriber terminals. Background Art

[2] Currently, broadcast signals are chiefly provided from a local wired broadcasting company to respective homes through a cable network. If the price of optical cable decreases in the future, there is a strong possibility that the cable network will be replaced with optical cables. Local wired broadcasting companies have been using coaxial cables, which are inexpensive and have a wide transmission band, to transmit broadcast signals. A coaxial cable is formed of a signal line, through which broadcast signals are transmitted, and a shield, which surrounds the signal line. Further, a coaxial cable is highly resistant to external noise and has a frequency bandwidth of 5 GHz. However, broadcast signals, which are transmitted by a local wired broadcasting company to respective subscriber terminals, do not exceed a frequency band of 900 MHz. Furthermore, not all of the frequency band is used. Therefore, most local wired broadcasting companies assign frequency bands that remain after the transmission of the broadcast signals to respective subscriber terminals through a cable network for Internet access service. Generally, a frequency band from 450 MHz to 550 MHz (downstream transmission band) is assigned for Internet access service.

[3] FIG. 1 is a diagram showing an example of a conventional network provision system for providing Internet access service and wire broadcast signals in a local wired broadcasting company.

[4] In the network provision system shown, an optical network device 10 is connected to a Cable Modem Termination System (CMTS), a reference signal generator, a Video On Demand (VOD) signal converter, and a head-end device through an Optical Transmitter (OTX) and an Optical Receiver (ORX). The head-end device and the VOD signal converter are devices that convert broadcast content, provided through a Program Provider (P.P.) or a VOD server, into optical signals and transmit the optical signals to the optical network device 10. The reference signal generator generates a reference signal for synchronization among the CMTS, the optical network device, and subscriber terminals. The CMTS assigns the optical network device 10 a frequency band for Internet access, and authenticates respective subscriber terminals. A device, such as a Trunk Bridge Amplifier (TBA) 60, is necessary between the optical network device 10 and tap-off units 50a to 50c in a hybrid network in which network signals and wire broadcast signals are provided through coaxial cables. When the cable network, through which broadcast signals are transmitted, branches off, and thus a plurality of trunk lines is formed, the TBA 60 compensates for the loss of branched broadcast signals, the loss of the network signals, and tap-off losses. In the system configured as described above, the optical network device 10 uses frequency bands for upstream transmission and downstream transmission, which are different from frequency bands that subscriber terminals use. Generally, the subscriber terminal transmits network signals to the optical network device 10 (referred to as "upstream transmission") through a frequency band from 4 MHz to 520 MHz. Further, the optical network device 10 transmits network signals to respective subscriber terminals (referred to as "downstream transmission") through a frequency band from 450 MHz to 550 MHz. Since the frequency bands of the network signals used for the upstream transmission and the downstream transmission between the optical network device 10 and the respective subscriber terminals are different from each other, the TBA 60 needs separate amplifiers for the upstream transmission and the downstream transmission between the optical network device 10 and the respective subscriber terminals. In FIG. 1, the TBA 60 includes an upstream amplifier 6OH for amplifying the upstream transmission band and a downstream amplifier 6OL for amplifying the downstream transmission band. However, the conventional network system using cable networks divides the downstream transmission band (for example, 450 MHz to 550 MHz) supplied from the optical network device 10 to the TBA 60 on the basis of the number of subscriber terminals and provides divided downstream transmission bands to respective subscriber terminals. Therefore, as the number of subscriber terminals that access the optical network device 10 increases, the frequency band that is assigned to each subscriber terminal is reduced, thereby causing a reduction in transmission speed. This is because the optical network device 10 divides the frequency band assigned thereto on the basis of the number of subscriber terminals and provides the divided frequency bands to respective subscriber terminals. Therefore, the available frequency band is limited in proportion to the number of wire broadcast signals that are transmitted. Accordingly, the conventional TBA 60 is configured to amplify and relay only the frequency bands assigned for upstream transmission and downstream transmission between the optical network device 10 and a user terminal. According to the above-descried configuration, the conventional TBA 60 uses a diplexer having the structure shown in FIG. 2 so as to correspond two frequency bands to a single port. The shown diplexer includes an I/O port connected to the optical network device 10, a High Pass Filter (HPF) for upstream transmission with subscriber terminals, and a Low Pass Filter (LPF) for downstream transmission with the subscriber terminals. The HPF and the LPF divide a frequency band into an upstream transmission band and a downstream transmission band, and amplify the divided upstream transmission band and downstream transmission band. Here, as shown in FIG. 2, if a diplexer having a structure for dividing a frequency band into two frequency bands mediates between the optical network device 10 and the subscriber terminal, only two bands, namely, the upstream transmission band and the downstream transmission band, can be amplified through cable networks. Therefore, there is a problem in that it is difficult to change the structure of a network system that uses the existing wired network. Accordingly, the present invention provides a trunk bridge amplifier that enables three or more frequency bands to correspond to a single I/O port while being compatible with an existing trunk bridge amplifier, thereby being able to assign a new frequency band for network communication. Disclosure of Invention Technical Problem

[5] Accordingly, an object of the present invention is to provide a trunk bridge amplifier that enables three or more frequency bands to correspond to a single I/O port while being compatible with an existing trunk bridge amplifier, thereby being able to assign a new frequency band for network communication. Technical Solution

[6] In order to accomplish the above object, the present invention provides a trunk bridge amplifier, the trunk bridge amplifier having a plurality of diplexers each for performing division into at least two frequency bands, and at least one amplifier for amplifying the resulting frequency bands, including: a bidirectional amplifier; the diplexer performs division into an upstream frequency band, a downstream frequency band, and a first frequency band, and includes a high frequency band connection terminal for separately performing division on the first frequency band; and the first frequency band is provided to the bidirectional amplifier, and an input/output (I/O) terminal of the bidirectional amplifier is connected to the high frequency band connection terminal of the diplexer and is then driven, so that a structure of a trunk bridge amplifier for the upstream frequency band and the downstream frequency band is not changed.

[7] Preferably, the bidirectional amplifier includes a filter for passing any one of the frequency bands therethrough, and an amplifier for amplifying the frequency band selected by the filter.

[8] The diplexer may be configured such that a low pass filter, a medium band pass filter, and a high pass filter respectively correspond to the downstream transmission band, the upstream transmission band, and the first transmission band.

[9] The diplexer may include a first diplexer connected to the optical network device, and a second diplexer connected to the tap-off units. Further, the second diplexer may be one or more in number.

[10] The diplexer includes filters configured to correspond respectively to the upstream transmission band and the downstream transmission band, and to pass only corresponding frequency bands therethrough; a housing for accommodating the filters; and a connection terminal provided on one side of the housing, and connected to the high pass amplifier.

[11] Preferably, the housing further includes a filter corresponding to the first transmission band.

[12] The connection terminal may be inserted into the housing.

[13] The connection terminal may be formed to protrude from the housing.

Advantageous Effects

[14] The trunk bridge amplifier according to the present invention does not change its structure, in which an existing trunk bridge amplifier transmits and receives network signals only via an upstream transmission band and a downstream transmission band, thereby maintaining compatibility with the existing trunk bridge amplifier, and employing a new frequency band for the transmission of network signals through an existing wired broadcasting network.

Brief Description of the Drawings [15] FIG. 1 is a diagram showing an example of a network provision system for providing Internet access service and broadcast signals in a local wired broadcasting company;

[16] FIG. 2 is a conceptual view showing a conventional diplexer;

[17] FIG. 3 is a diagram showing an example in which a trunk bridge amplifier according to the present invention is combined with an optical network device and is used in conjunction with the optical network device; [18] FIG. 4 is a diagram conceptually showing a method of forming a multichannel using an optical network device; [19] FIG. 5 is a conceptual diagram showing a trunk bridge amplifier according to an embodiment of the present invention; [20] FIG. 6 is a diagram showing an example of a high pass amplifier connected to a port CP_1 shown in FIG. 5; [21] FIGS. 7 to 9 are diagrams conceptually showing a compensation method of a first equalizer, shown in FIG. 5; and [22] FIG. 10 is a view showing the appearance of an example of a first diplexer, shown in FIG. 5.

[23] * Description of reference numerals of principal elements in the drawings *

[24] 100: optical network device

[25] 200: trunk bridge amplifier

[26] 210 to 240: first to fourth diplexers

Mode for the Invention

[27] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[28] FIG. 3 is a diagram showing an example in which a trunk bridge amplifier according to the present invention is combined with an optical network device and is used in conjunction with the optical network device.

[29] A trunk bridge amplifier 200 according to the present invention may be connected to an optical network device 100, capable of forming a multichannel for one frequency band, and may be used in conjunction with the optical network device. Alternatively, the trunk bridge amplifier 200 may be connected to a general Optical Node Unit (ONU) and a separate optical network device capable of forming a multichannel and may be used in conjunction with the ONU and the optical network device. Here, the term "multichannel" means that a single frequency band is repeatedly used by providing a frequency band, assigned to the optical network device 100 for network access service, to respective sectors, which are independent from each other, in the same manner. This will be described with reference to FIG. 4.

[30] FIG. 4 is a diagram conceptually showing a method of forming a multichannel using an optical network device.

[31] The method of forming a multichannel described in conjunction with the present invention employs a network characteristic of a general wired cable network, that is, the characteristic in which the optical network device 100 provides the same frequency band to respective sectors, so that a single frequency band can be repeatedly used, thereby increasing the the frequency band assigned to the optical network device 100 by the number of times it is reused. That is, the method assigns the same frequency band to respective independent sectors (sectors 1 to 4) in accordance with the characteristic of a wired broadcasting network, and allows each of the sectors to divide the same frequency band and to use resulting frequency bands, thereby increasing the frequency band to be provided to each of the sectors (sector 1 to sector 4), rather than dividing and providing a frequency band, assigned by the optical network device 100, via a tap-off unit 20 disposed in a sector (for example, sector 1) to which a plurality of subscriber terminals belongs. This uses the characteristic of an existing wired broadcasting network, which is different from a network constructed to access the Internet. That is, in the general wired broadcasting network, a set of a predetermined number of subscriber terminals is assigned to a sector, which is not connected to another sector. This is the characteristic of a cable network, which is different from that of a general network having a ring topology to improve network reliability. According to the present invention, a multichannel is formed for a frequency band that can be assigned by the optical network device 100, so that the sectors connected to the optical network device 100 use the same frequency band. This will be described in detail below.

[32] In the drawing, a Multi Dwelling Unit (MDU) 101 is disposed at the location where the sectors 1 to 4 first branch off, and the disposed MDU 101 supplies the same frequency band to the respective sectors 1 to 4. Generally, since a cable network is constructed to divide one frequency band and provides resulting frequency bands to the respective sectors, the frequency band to be assigned to each of the subscriber terminals (for example, reference numbers 1 to 4) should be decreased when the number of subscribers increases, which results in a decrease in the data transmission path for each of the subscriber terminals. According to the present invention, in order to solve the above-described problem, channel cards 111 to 114, which use the frequency band assigned by the wired broadcasting company, are corresponded to the respective sectors 1 to 4, and each of the channel cards 111 to 114 establishes a communication channel with each of the sectors 1 to 4 through the same frequency band. For example, if the channel card 111 uses a frequency band from 975 MHz to 1525 MHz, the channel cards 112, 113, and 114 also use the same frequency band from 975 MHz to 1525 MHz as the channel card 111. Each of the channel cards 111 to 114 has the form of an Ethernet card, which may be attachable/detachable to/from a motherboard 110 having a bus structure, and has a function of performing Radio Frequency (RF) communication with each of the sectors 1 to 4. The shown MDU corresponds to the sectors 1 to 4, and includes the channel cards 111 to 114 for dividing the same frequency band and providing communication channels to the subscriber terminals (for example, 1 to 4), an Optical Transmitter (OXT) connected to a wired broadcasting company through an optical cable and configured to convert data, received from the channel cards 111 to 114, into optical signals and transmit the optical signals to the wired broadcasting company, an Optical Receiver (ORX) for converting optical data, received from the wired broadcasting company, into electronic signals, and a motherboard 110 configured to have a bus structure and connected to the channel cards 111 to 114.

[33] In the drawing, the channel cards 111 to 114 use the same frequency band A, B, C, and D. The channel card 111 provides the frequency band, composed of sections A, B, C, and D, to the tap-off unit 20, which is positioned in the sector sector 1. The tap-off unit 20 divides the frequency band into four frequency sections A, B, C, and D, and distributes the frequency sections to the respective subscriber terminals 1 to 4. In the case where the subscriber terminals are four in number, each of the subscriber terminals 1 to 4 may perform data communication via a frequency section that is obtained by dividing the frequency band, assigned by the channel card 111, into four equal frequency sections. In this case, as shown in the drawing, when the optical network device 100 forms a multichannel, the trunk bridge amplifier 200, which extends the network from the optical network device 100 to the tap-off units or sectors, should be capable of corresponding to three or more frequency bands. This is required in order for the trunk bridge amplifier 200 according to the present invention to be compatible with the deployed existing wired broadcasting network. For a network using the existing wired broadcasting network, an optical network device is designed to process a frequency band for upstream transmission and a frequency band for downstream transmission (that is, the optical network device is constructed to process two frequency bands). That is, the existing network uses a frequency band from 4 MHz to 52 MHz for upstream transmission, and a frequency band from 450 MHz to 550 MHz for downstream transmission. The multichannel described in the present invention is intended to additionally assign a frequency band from 975 MHz to 1525 MHz to the cable network, so that a wider frequency band is assigned to each of the subscriber terminals belonging to each sector, thereby increasing the network transmission rate between each subscriber terminal and the optical network. Therefore, the trunk bridge amplifier according to the present invention should be constructed to be capable of processing the existing upstream transmission frequency band, the existing downstream transmission frequency band, and the frequency band from 975 MHz to 1525 MHz. This will be described in detail with reference to FIG. 5.

[34] FIG. 5 is a conceptual block diagram showing a trunk bridge amplifier according to an embodiment of the present invention.

[35] The shown trunk bridge amplifier 200 includes a first port Pl, connected to the optical network device 100, and second to fourth ports P2 to P4 connected to respective sectors or tap-off units directed toward respective sectors. In the direction from the first port Pl to the second port P2, a first diplexer 210, a first equalizer 211, a first attenuator 212, a first amplifier 213, a second attenuator 214, a gain control unit 215, a second amplifier 216, and a second diplexer 220 are connected to each other, and, in the direction from the second port P2 to the first port Pl, a third attenuator 221, a low pass filter LPF, a third amplifier 223, a fourth attenuator 224, and a second equalizer 225 are connected to each other. Furthermore, a third diplexer 230, a fifth attenuator 231, a sixth attenuator 241, a fourth amplifier 233, a seventh attenuator 232, an eighth attenuator 242, and a fifth amplifier 243 are connected to each other between the third port P3 and the fourth port P4. Moreover, a third equalizer 226 and a high pass filter 227 are connected to each other between the node where the seventh attenuator 232 is connected to the eighth attenuator 242 and a second diplexer 220.

[36] The first diplexer 210 is connected to the first port Pl, and is connected to the optical network device 100, which forms the multichannel, through the first port Pl. The first diplexer 210 includes a low pass filter L for passing a downstream transmission band from 4 MHz to 52 MHz therethrough, a medium band pass filter M for passing a frequency band from 450 MHz to 550 MHz, assigned in the general cable network for downstream transmission, and a high pass filter H for passing a frequency band from 975 MHz to 1525 MHz, in which the multichannel according to the present invention is formed. Each of the low pass filter, the medium band pass filter, and the high pass filter is connected to the optical network device 100 through the first port Pl, and selectively passes a frequency band used for upstream transmission, downstream transmission, or high frequency band transmission between a subscriber terminal and the optical network device 100. In this case, the first diplexer 210 provides a medium band frequency to the first equalizer 211, a low band frequency to the second equalizer 225, and a high band frequency to a port CP_1, which will be described later. Thereby, the first diplexer 210 allows frequencies in different frequency bands (low, medium, and high frequency bands) to communicate with the optical network device 100 through one port Pl.

[37] Meanwhile, in order for the first diplexer 210 to be compatible with the existing trunk bridge amplifier, it is preferable that the first diplexer 210 be implemented in the form shown in FIG. 10. A general diplexer is manufactured in the form of a socket and is designed to be attachable/detachable to/from the body of the trunk bridge amplifier so as to handle the occurrence of failure and to adjust frequency bands.

[38] FIG. 10 is a view showing the appearance of an example of the first diplexer 210 shown in FIG. 5.

[39] As shown in the drawing, the first diplexer 210 includes LC filters (not shown) respectively corresponding to a low frequency band, a medium frequency band and a high frequency band, a housing 250 for accommodating the LC filters, and a high frequency band connection terminal 251 provided on one side of the housing 250. Although the high frequency band connection terminal 251 is illustrated as being inserted into the housing in the drawing, the high frequency band connection terminal 251 may be formed to protrude from the housing 250, or the high frequency band (for example, a band from 975 MHz to 1525 MHz) connection terminal may be formed to be positioned outside the housing 250 using a separate connector. Here, the example shown in FIG. 10 may be applied to the second to fourth diplexers 210 to 240 as well as the first diplexer 210 in the same manner.

[40] The first equalizer 211 compensates for the loss of the downstream frequency band among frequency bands transmitted from the optical network device 100. RF signals are transmitted and received between the optical network device 100 and the trunk bridge amplifier 200. Since the optical network device 100 and the trunk bridge amplifier 200 are connected to each other through a coaxial cable, RF signals experience signal attenuation. At this time, the signals in the high frequency band are obviously attenuated compared to the signals in the low frequency band. Therefore, the first equalizer 211 performs compensation so that the intensities of the signals in the low and high frequency bands become uniform. This will be described in detail with reference to FIGS. 7 to 9.

[41] FIGS. 7 to 9 conceptually show the compensation method of the first equalizer 211 shown in FIG. 5.

[42] First, FIG. 7 shows the signal characteristics of a frequency band that passes through the coaxial cable. As shown in the drawing, in the case of a coaxial cable, it can be seen that signals are obviously attenuated in the high frequency band compared to those in the low frequency band. FIG. 8 shows gains for respective frequency bands, which are obtained by the first equalizer 211. The gain of the first equalizer 211 is set to a low value for the low frequency band, but to a high value for the high frequency band. FIG. 9 shows frequency characteristics compensated for by the first equalizer 211. As shown in the drawing, the frequency bands output from the first equalizer 211 are level with each other over a range from the low frequency band to the high frequency band due to the gain adjustment of the first equalizer 211. Here, the compensation method described in conjunction with FIGS. 7 to 9 is also applied to the second equalizer 225 and the third equalizer 226 as well as the first equalizer 211, so that redundant descriptions of the equalizers (second equalizer 225 and the third equalizer 226) will be omitted below.

[43] The first attenuator 212 decreases the size of the output signal of the first equalizer

211 to a desired signal size that is required by an input terminal of the first amplifier 213. The first amplifier 213 amplifies the output signal of the first attenuator 212, and provides the amplified signal to the second attenuator 214. The second attenuator 214 decreases the size of the output signal of the first amplifier 213 to a desired signal size that is required by the gain control unit 215. The gain control unit 215 provides the signal having the reduced size to the second amplifier 216. At this moment, the gain control unit 215 receives an output from the output terminal of the second amplifier 216 as an input, and performs control so that the output of the second amplifier 216 is driven by a constant gain. If the output of the second amplifier 216 exceeds a predetermined reference value, the gain control unit 215 reduces the size of the signal to be applied to the second amplifier 216. Otherwise, the gain control unit 215 increases the size of a signal to be applied to the second amplifier 216. The output of the second amplifier 216 is supplied to the second diplexer 220 and the third equalizer 226. The output terminal of the second amplifier 216 is connected to the medium band pass filter of the second diplexer 220, and supplies the downstream transmission band of the optical network device through the second port P2.

[44] The third attenuator 221 is connected to the low pass filter L of the second diplexer

220, and decreases the size of the signal in the upstream transmission band, which is received through the second diplexer 220, to a desired size that is required by the third amplifier 223. At this time, the low pass filter 222 is provided between the third attenuator 221 and the third amplifier 223. The low pass filter 222 passes a downstream frequency band that remains in signals in an upstream transmission band supplied through the diplexer 220. The fourth attenuator 224 decreases the output of the third amplifier 223 to a desired signal size that is required by the second equalizer

225. The second equalizer 225 obtains gains for the output of the fourth attenuator 224 and supplies the output of the third attenuator 221 to the first diplexer 210. The first diplexer 210 transmits signals in the upstream transmission band, which are output from the second equalizer 225, to the optical network device 100 through the first port Pl. Here, in the embodiment according to the present invention, the relationship between the optical network device 100 and the trunk bridge amplifier 200 has been mainly explained. However, the trunk bridge amplifier 200 according to the present embodiment may be connected to a separate trunk bridge amplifier, other than the optical network device 100. At this moment, the first port Pl may be connected to the port of the separate trunk bridge amplifier (a port other than the first port of the separate trunk bridge amplifier). The fifth attenuator 231 and the sixth attenuator 241 are connected to a node connected between the third attenuator 221 and the low pass filter 222. The fifth attenuator 231 and the sixth attenuator 241 have the same function as the above-described third attenuator 221, and supply an upstream transmission band signal, which is applied from the third and fourth ports P3 and P4, to the low pass filter 222. The output terminal of the second amplifier 216 is connected to the third equalizer

226. The third equalizer 226 obtains gains of the output signal of the second amplifier 216 and supplies the output signal of the second amplifier 216 to the high pass filter

227. Here, the high pass filter 227 passes a stopped frequency band, which is not necessarily the high frequency band (for example, a frequency band from 975 MHz to 1525MHz) described in the present invention. The high pass filter 227 supplies an upstream transmission band (frequencies in the medium band) to the seventh attenuator 232 and the eighth attenuator 242. Each of the seventh attenuator 232 and the eighth attenuator 242 changes the upstream transmission band to a desired signal size that is required by respective input terminals of the fourth amplifier 233 and the fifth amplifier 243, and provides the signals having a changed size to the third diplexer 230 and the fourth diplexer 240. That is, the first diplexer 210, connected to the first port Pl, provides an upstream transmission frequency to the optical network device 100 (or the separate trunk bridge amplifier to be connected to the trunk bridge amplifier described in the present embodiment, which will be omitted below), receives signals in a downstream frequency band from the optical network device 100, or transmits the signals through the second to fourth diplexers 220 to 240 connected to the second to fourth ports P2 to P4, respectively. At this moment, each of the second to fourth ports P2 to P4 provides the signals in the upstream transmission band, which is transmitted from a tap-off unit (not shown, called a "tap-off), to the first diplexer 210 so that the first diplexer 210 provides the signal in the upstream transmission band to the optical network device 100.

[45] FIG. 6 is a diagram showing an example of a high pass amplifier connected to the port CP_1 shown in FIG. 5.

[46] The shown high pass amplifier is provided between ports CP_1 and CP_2 and is configured to have channel-based amplifiers CHl to CH4 and filters 201 to 208 which are connected to the channel-based amplifiers CHl to CH4. As described in conjunction with FIG. 4, the trunk bridge amplifier 200 according to the present invention employs a multichannel to use a high band frequency (from 975 MHz to 1525 MHz) for network signal transmission and causes each of the channel cards 111 to 114 to divide the high band frequency (from 975 MHz to 1525 MHz) into four sections so as to correspond to the respective sectors. Therefore, the filters 201 to 208 for passing respective frequency bands of the channel cards 111 to 114 and bidirectional amplifiers CHl to CH4 are necessary. In the drawing, the number of bidirectional amplifiers CHl to CH4 is determined according to the number of channel cards. For example, in the case where the channel cards 111 to 114 are four in number, the number of bidirectional amplifiers CHl to CH4 may be set to four. The filters 201 to 208 are provided on both sides of the corresponding bidirectional amplifiers CHl to CH4, and are configured to pass only desired frequency bands to be amplified by the bidirectional amplifiers CHl to CH4. Here, two filters are provided for the respective bidirectional amplifiers CHl to CH4 so as to amplify frequencies transmitted upstream in the direction from the port CP2 to the port CPl while amplifying frequencies transmitted downstream in the direction from the port CPl to the port CP2. At this moment, each of the bidirectional amplifiers CHl to CH4 is connected with two filters. For example, the bidirectional amplifier CHl is connected with the filters 201 and 208 and the bidirectional amplifier CH2 is connected with the filters 202 and 207. This structure is configured to amplify network signals transmitted in the direction from the port CP_1 to the port CP_2 and network signals transmitted in the direction from the port CP_2 to the port CP_1. Therefore, for example, the filters 201 and 208 connected to the bidirectional amplifier CHl have the same frequency characteristic. Accordingly, the trunk bridge amplifier 200 according to the present invention may add a new frequency band for a cable network deployed by a wired broadcasting company and form a new communication network via the added frequency bands without changing the structure of an existing trunk bridge amplifier. Industrial Applicability

[47] As described above, a trunk bridge amplifier according to the present invention does not change a structure in which an existing trunk bridge amplifier transmits and receives network signals only via an upstream transmission band and a downstream transmission band, thereby maintaining compatibility with the existing trunk bridge amplifier, and employing a new frequency band for the transmission of network signals through an existing wired broadcasting network.

[48]

Claims

[1] A trunk bridge amplifier, the trunk bridge amplifier including a plurality of diplexers each for performing division into at least two frequency bands, and at least one amplifier for amplifying the resulting frequency bands, comprising: a bidirectional amplifier; wherein the diplexer performs division into an upstream frequency band, a downstream frequency band, and a first frequency band, and includes a high frequency band connection terminal for separately performing division on the first frequency band; and wherein the first frequency band is provided to the bidirectional amplifier, and an input/output (I/O) terminal of the bidirectional amplifier is connected to the high frequency band connection terminal of the diplexer and is then driven, so that a structure of a trunk bridge amplifier for the upstream frequency band and the downstream frequency band is not changed.

[2] The trunk bridge amplifier using a multichannel diplexer according to claim 1, wherein the bidirectional amplifier comprises: a filter for passing any one of the frequency bands therethrough; and an amplifier for amplifying the frequency band selected by the filter.

[3] The trunk bridge amplifier using a multichannel diplexer according to claim 1, wherein the diplexer is configured such that a low pass filter, a medium band pass filter, and a high pass filter respectively correspond to the downstream transmission band, the upstream transmission band, and the first transmission band.

[4] The trunk bridge amplifier using a multichannel diplexer according to claim 1, wherein the diplexer comprises: a first diplexer connected to the optical network device; and a second diplexer connected to the tap-off units, wherein the second diplexer is one or more in number.

[5] The trunk bridge amplifier using a multichannel diplexer according to claim 1, wherein the diplexer comprises: filters configured to respectively correspond to the upstream transmission band and the downstream transmission band, and to pass only corresponding frequency bands therethrough; a housing for accommodating the filters; and a connection highpass terminal provided on one side of the housing, and connected to the high pass amplifier.

[6] The trunk bridge amplifier using a multichannel diplexer according to claim 5, wherein the housing further comprises a filter corresponding to the first transmission band. [7] The trunk bridge amplifier using a multichannel diplexer according to claim 5, wherein the connection high pass terminal is inserted into the housing. [8] The trunk bridge amplifier using a multichannel diplexer according to claim 5, wherein the connection high pass terminal is formed to protrude from the housing.