JP2011139539A - Complex bidirectional relay amplifier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a complex relay amplifier to which an optical fiber can be connected easily, and a network system employing the same. <P>SOLUTION: In a conventional bidirectional relay amplifier, a terminal T is provided in which a photoelectric conversion unit 59 can be mounted. When connecting input/output of amplifiers 45a, 45b to a coaxial cable system, only an automatic amplification factor controller (AGC) is connected to the terminal T. When connecting the input/output to an optical fiber 25, on the other hand, the AGC is demounted, the photoelectric conversion unit 59 is mounted, and its input/output is connected to the amplifiers 45a, 45b. Furthermore, at the same time, an attenuator of the coaxial cable system is demounted, and termination resistors r<SB>a</SB>, r<SB>b</SB>are provided in the disconnected upstream-side terminal T. This is used as a complex relay amplifier. Consumers subsequent to the complex relay amplifier are directly connected with a central unit by the optical fiber 25. Namely, the consumers of a network system are bisected. Since the consumers are bisected, communication efficiency is improved. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a relay amplifier that amplifies and transmits a signal of a network system. In particular, the present invention relates to a composite relay amplifier that can switch upstream input / output or upstream output from a coaxial cable system to an optical fiber system simply by mounting an optical fiber photoelectric converter on the coaxial cable relay amplifier. The present invention can be applied to a CATV system that performs bidirectional data communication.

  Conventionally, there are CATV systems that transmit terrestrial broadcasts and satellite broadcasts. In recent years, data communication such as the Internet has been added to the network system, which has improved convenience. FIG. 13 shows a CATV network system. The CATV network system includes a central device 10 provided in a CATV station, an optical fiber (main line) 20 extended from the central device 10, a photoelectric conversion type relay device A that photoelectrically converts and relays the input and output of the optical fiber, It comprises a relay device B that relays signals, a branch device 21 that branches from the relay device A, and a customer (premises network) 30 that is connected to the branch line 21.

  The consumer 30 includes, for example, distributors 31 and 34 that distribute signals from the branch line 21, a TV device 32 that is connected to the distributor 34, and a computer device 33. The consumer performs terrestrial broadcasting, satellite broadcasting reception, and data communication such as the Internet using the terminal device. At this time, the TV signal and the downstream data signal from the central apparatus 10 are transmitted in a broadband manner, for example, in the downstream band of 70 MHz to 770 MHz, and the upstream data signal is transmitted in the upstream band of 10 to 55 MHz. Data communication such as the Internet is performed using a predetermined band among the above bands.

Problems to be solved by the invention

  However, with the spread of the Internet in recent years, there has been a problem that the use of the predetermined band increases, and when many users use it simultaneously, the waiting time for using the band increases, resulting in a decrease in communication efficiency.

The present invention has been made to solve this problem, and an object of the present invention is to make any relay amplifier of a conventional network system a composite relay amplifier to which an optical fiber is connected, and thereby a conventional network system. (Customer) is divided, and as a result, the standby time is reduced to improve the communication efficiency.
Another object of the present invention is to provide a composite relay amplifier in which a photoelectric converter can be easily attached.
Further, even if a conventional network system is divided by introducing a compound relay amplifier, the quality of the divided upstream data communication is maintained.
It should be noted that the above object is an object that each invention achieves individually, and that each invention should not be construed as achieving all the above objects.

Means and actions / effects for solving the problems

  The present invention is arranged in a coaxial transmission line of a CATV network system in which a signal is transmitted from a central device of a CATV station in the downstream direction of each consumer at the end, and a signal is transmitted from each customer in the upstream direction of the central device. A bi-directional relay amplifier provided, a first demultiplexing filter provided on the central device side, a second demultiplexing filter provided on the customer side, a first demultiplexing filter, and a second demultiplexing filter A first attenuator connected to the downstream terminal of the first demultiplexing filter, a first equalizer connected to the first attenuator, a downstream amplifier that amplifies the downstream signal, An upstream amplifier that amplifies the upstream signal, a second equalizer that equalizes the output signal of the upstream amplifier, a first terminal to which the second equalizer is connected, and a second terminal, which are provided between the wave filter and the second branching filter Pair with the upstream terminal of the 1st demultiplexing filter In the bidirectional repeater amplifier comprising the detachable second attenuator, the second attenuator is detached from the first terminal and the upstream terminal, and a terminating resistor is attached to the upstream terminal and the ground terminal, and the second equalizer A photoelectric conversion unit for inputting an output signal and converting the output signal into an optical signal is disposed in an empty space of the bidirectional relay amplifier housing, and the optical signal converted by the photoelectric conversion unit is transmitted to the central device side. A composite bidirectional relay characterized in that the output end of the photoelectric conversion unit is connected to an optical fiber, the downstream signal is an electrical signal, the upstream output signal is an optical signal, and the electrical signal and the optical signal are combined. It is an amplifier.

[Invention of original application]
The following is a description of the invention of the original application. The housing is provided with a space and a terminal for mounting a photoelectric converter or a photoelectric conversion unit to which a bidirectional coaxial amplifier and an optical fiber are connected. When the photoelectric converter or the photoelectric conversion unit is attached to the terminal, that is, a space provided in advance, the input / output of the bidirectional coaxial amplifier is switched to the optical fiber system by changing the connection of the terminal, for example. On the contrary, when the photoelectric converter or the photoelectric conversion unit is removed, the coaxial cable system is switched by changing the terminal connection, for example. That is, the input / output of the bidirectional coaxial amplifier is switched between the optical fiber system and the coaxial cable system in accordance with the attachment / detachment of the photoelectric converter or the photoelectric conversion unit. That is, it becomes a composite repeater amplifier that can immediately respond to the demand for optical fiber service.

In addition, the input / output switching of the bidirectional coaxial amplifier is performed by a switch device linked to the attachment / detachment of the photoelectric converter or the photoelectric conversion unit. At this time, the changeover switch device is, for example, a mechanical press switch.
In other words, when the operator attaches the photoelectric converter or the photoelectric conversion unit, the optical fiber system is automatically switched, for example, by the pressing force at the time of attachment. Conversely, if the photoelectric converter is removed, it can be switched to the coaxial cable system again. That is, the operator does not need to perform various wiring operations by removing the coaxial cable amplifier and attaching an optical fiber amplifier including a photoelectric converter. That is, the composite relay amplifier is excellent in workability.

The bidirectional coaxial amplifier is a bidirectional coaxial amplifier having an automatic gain control device, and the space where the photoelectric converter or photoelectric conversion unit is mounted is the space after the automatic gain control device is removed. It is characterized by.
When the bidirectional coaxial amplifier is an automatic gain control amplifier, a so-called AGC amplifier, an automatic gain control device is usually added to the bidirectional amplifier. Therefore, if this is removed and manual gain control is performed, a space in which the photoelectric converter or the photoelectric conversion unit is mounted is generated. Therefore, if a photoelectric converter or a photoelectric conversion unit can be mounted in the space, it is not necessary to newly provide a space for mounting the photoelectric converter. That is, it is possible to reduce the size while having an advanced function that can be switched between an optical fiber system and a coaxial cable system.

The terminal to which the photoelectric converter or the photoelectric conversion unit is attached is exposed to a space after the automatic gain control device is removed.
That is, a terminal for mounting the photoelectric converter or the photoelectric conversion unit appears in the space after the automatic gain control device is removed from the bidirectional coaxial amplifier. That is, the operator only needs to remove the automatic gain control device from the bidirectional coaxial amplifier and then attach the photoelectric converter or photoelectric conversion unit. Furthermore, the composite relay amplifier is reduced in size.

In addition, a photoelectric converter or a photoelectric conversion unit having an optical fiber connected to a space for mounting the photoelectric converter or the photoelectric conversion unit is mounted.
In a composite relay amplifier equipped with a photoelectric converter or a photoelectric conversion unit, the transmission path upstream from it is an optical fiber, and the transmission path downstream from it is a conventional coaxial cable. That is, a conventional one-system network system can be divided into a plurality of parallel network systems. If this composite relay amplifier is used, the network system is divided into a plurality of parallel systems, so that the transmission efficiency of data communication can be improved.

In addition, a termination resistor is connected to the end of the coaxial cable system that is disconnected by switching input / output.
When the photoelectric converter or the photoelectric conversion unit is attached, the input / output is switched, whereby the input / output of the coaxial cable system is disconnected and the end is opened. If the end is open, reflection occurs there, and the quality of data communication deteriorates in the network system upstream of the composite relay amplifier. Therefore, when the photoelectric converter or the photoelectric conversion unit is attached, a terminal resistor is provided at the end of the disconnected coaxial cable system. Thereby, the quality of the network system upstream from the composite relay amplifier, that is, the divided conventional network system can be maintained.

Further, the termination resistor is connected in conjunction with the mounting of the photoelectric converter or the photoelectric conversion unit.
For example, the interlocking means that it is automatically performed with the mounting of the photoelectric converter or the photoelectric conversion unit. For example, a photoelectric converter or a photoelectric conversion unit and a termination resistor are provided on the same substrate, and the substrate is connected to a predetermined terminal. Thereby, a termination resistor is provided at a predetermined location simultaneously with the mounting of the photoelectric converter or the photoelectric conversion unit. That is, the input / output switching and the termination processing of the separated termination are completed with one installation.
Alternatively, for example, the configuration is such that the mounting of the photoelectric converter or the photoelectric conversion unit and the input / output changeover switch device are interlocked. The changeover switch device is, for example, a push-type mechanical switch. When the operator attaches the photoelectric converter or photoelectric conversion unit, the changeover switch device is pressed, the input / output is switched, and the end of the coaxial cable system is automatically connected to the termination resistor by the switch device in conjunction with this. To. That is, it is not necessary for the operator to manually connect the termination resistor each time the photoelectric converter or the photoelectric conversion unit is mounted. Therefore, the composite relay amplifier is more convenient.

  In addition, the photoelectric converter or the photoelectric conversion unit is bidirectional. As a result, both the upstream and downstream directions are connected to the central apparatus by new optical fibers. That is, the communication efficiency is improved in both the uplink direction and the downlink direction.

In addition, a power pass filter that passes power between the input terminal and the output terminal is provided.
Thereby, even if the network system is divided by the photoelectric converter, the power system is not divided. Power is supplied as before and the relay amplifier functions as before. In addition, a relay amplifier or the like can be newly added. That is, it is not necessary to newly provide a power supply line. Therefore, the composite relay amplifier according to any one of claims 1 to 8 can be realized efficiently at low cost.

The network system using the composite relay amplifier is a network system including a central device, a plurality of relay devices, and a plurality of terminal devices, and any one of the relay devices is defined in any one of claims 1 to 9. The composite repeater amplifier according to Item 1 is characterized in that a single network system extended from the central device is a multiple network system extended in parallel from the central device via an optical fiber.
If one of the relay amplifiers of the conventional network system is replaced with a composite relay amplifier equipped with a photoelectric converter, the conventional one network system can be divided into a plurality of network systems. The network system divided into a plurality is connected in parallel to the central device by direct optical fiber. That is, since the consumer is divided into a plurality of parts, the waiting time is reduced as compared with the conventional case even if the access of the consumer is concentrated. That is, customers of each network system can perform data communication efficiently.

A network system using a composite relay amplifier is a network system composed of a central device, a plurality of relay devices, and a plurality of terminal devices. The network system includes a composite relay amplifier at a predetermined location of the network system, It is characterized by preparing for the expansion of a new network system.
Currently, the number of customers who use network systems continues to increase, and there is no sign that the trend will decline in the future. In other words, although it is appropriate now, there is a possibility that the data communication efficiency will decrease with an increase in consumers in the future.
Therefore, the composite relay amplifier according to any one of claims 1 to 9 is provided in advance in a place where communication efficiency may be lowered in the future. However, at present, the service is performed using a coaxial cable system. As a result, even if the number of customers increases in the future, it is possible to immediately switch to an optical fiber service. Therefore, it becomes an efficient network system which prepares for future increase of consumers and maintains the current network system.
In the future, the portion where the communication efficiency may be lowered includes the relay amplifier at the final stage of the current network system. That is, it includes the case where the current network system is extended in the future. If the composite relay amplifier of the present invention is provided at the final stage, it can cope with future extensions.

The network system is a CATV network system using a composite relay amplifier.
The CATV network system is now an important network system that can be used not only for TV reception but also for high-speed Internet. In the future, with the increase in data capacity, the number of users will increase rapidly, and the communication efficiency is expected to decline. Therefore, if the network system of claim 10 or 11 is applied to a CATV network system, high-speed communication can be guaranteed for many customers in the future. In other words, not only TV reception but also an excellent network system that can cope with the future increase in data capacity and the increase in consumers can be achieved.

1 is a configuration diagram of a CATV network system to which a composite relay amplifier according to a first embodiment of the present invention is applied. 1 is a circuit diagram of a bidirectional relay amplifier according to a first embodiment of the present invention. 1 is a circuit diagram of a composite relay amplifier according to a first embodiment of the present invention. FIG. 6 is a circuit diagram of a composite relay amplifier according to a second embodiment of the present invention. FIG. 5 is a circuit diagram of a composite relay amplifier according to a third embodiment of the present invention. FIG. 6 is a circuit diagram of a composite relay amplifier according to a fourth embodiment of the present invention. The circuit diagram of the bidirectional relay amplifier which made AGC a substrate concerning the modification of the 1st example of the present invention. FIG. 6 is a circuit diagram of a composite relay amplifier according to a modification of the first embodiment of the present invention. FIG. 6 is a circuit diagram of a composite relay amplifier according to a modification of the first embodiment of the present invention. The circuit diagram of the bidirectional | two-way relay amplifier which made the branching filter and AGC based on the modification of 1st Example of this invention into a board | substrate. FIG. 6 is a circuit diagram of a composite relay amplifier according to a modification of the first embodiment of the present invention. The circuit diagram of the compound relay amplifier which concerns on the modification of 3rd Example of this invention. The block diagram of the CATV network system using the conventional bidirectional | two-way relay amplifier.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following Example.
(First embodiment)
FIG. 1 shows a CATV network system to which the composite relay amplifier of the present invention is applied. The figure is a system configuration diagram. CATV network system of this embodiment, the central unit 10 provided on the CATV station, an optical fiber 20, 25, the photoelectric type bidirectional repeater amplifier 40A, a coaxial cable 22, two-way relaying amplifier 40B _n, 40B _m, composite It comprises a relay amplifier 50, a branching coaxial cable 21, and a customer 30 connected to the branching coaxial cable 21. In addition, the structure of the consumer 30 is equivalent to a prior art example.
The photoelectric bidirectional relay amplifier 40A is a relay amplifier having a photoelectric converter (not shown), and is a relay amplifier that relays an optical signal in the upstream direction and an electrical signal in the downstream direction. The bidirectional relay amplifiers 40B _n and 40B _m are relay amplifiers that amplify and send electric signals bidirectionally. Note that n and m are integers representing indexes. Examples of the bidirectional relay amplifiers 40B _n and 40B _m include a main line amplifier, an extension amplifier, a distribution amplifier, a main line distribution amplifier, a branch amplifier, and a main line branch amplifier.

In the above configuration, the central unit 10, the photoelectric type bidirectional repeater amplifier 40A, two-way relaying amplifier 40B _n, branches path to the bidirectional repeater amplifier 40B _m coaxial cable 21, and so-called multi-drop type with customer 30 This network system is a conventional network system. In the conventional example, about 200 households are covered by this network system. This example, from the data communication increase in demand for Internet, for example, the next stage of the two-way relaying amplifier 40B _n replaced by composite relay amplifier 50 as shown, it to the central unit 10 with a new optical fiber 25 It is a connected configuration. That is, the feature of this embodiment is that the conventional network system is divided into two systems covering about 100 consumers.
Specifically, the photoelectric type from the central unit 10 via the optical fiber 20 two-way relaying amplifier 40A, the network system up to the two-way relaying amplifier 40B _n a single network system. In addition, another network system formed by the central apparatus 10, the optical fiber 25, the composite relay amplifier 50, and the subsequent customers 30 becomes a new network system. That is, as shown in the figure, the conventional network system is divided into two at the point A, upstream and downstream.

The reason why the conventional network system is divided into two when the composite relay amplifier 50 is used as shown in the figure will be described using the bidirectional relay amplifier 40B _n and the composite relay amplifier 50. Composite relay amplifier 50 is configured using a two-way relaying amplifier 40B _n. First, a two-way relaying amplifier 40B _n in FIG. The figure is a circuit diagram.
Way relaying amplifier 40B _n is demultiplexed filter 42 of RF connector 41,1 to-pair is an input terminal and an output terminal, the attenuator (ATT) 43a, 43b, an equalizer (EQ) 44a, 44b, an amplifier (Amp ) 45a, 45b, gain control (GC) 46, branching device 47, automatic gain control device (AGC) 49, (TILT) 48, and power pass filter 100, electrical communication chip 105, and predetermined components can be attached and detached. Terminal T (◎) and a housing 110. The amplifiers (Amp) 45a and 45b form a bidirectional coaxial amplifier.
With this configuration, for example, a downstream signal of 70 MHz to 770 MHz is amplified on the path a and transmitted downstream, and an upstream signal of 10 MHz to 55 MHz is amplified on the path b and transmitted upstream. Further, since the bidirectional relay amplifier 40B _n includes the power pass filter 100 and the electrical communication chip 105, the power from the power supply device 90 is energized upstream or downstream.

A composite relay amplifier 50 used in the present embodiment is shown in FIG. Attenuator (ATT) 43a of the features of the composite relay amplifier 50 is bi-directional repeater amplifier 40B _n, 43b, remove the automatic gain controller (AGC) 49, an automatic gain control system for a small (AGC) 49a and the photoelectric conversion A photoelectric converter unit 59 composed of a device (O / E) 51. Also, the attenuator (ATT) 43a, terminating resistors r _a to the terminal T by removing the 43 b, is that having a r _b.
Thereby, for example, the downstream signal transmitted from the central device through the optical fiber 25 is converted into an electrical signal by the photoelectric converter (O / E) 51 of the photoelectric conversion unit 59, and the equalizer (EQ) 44a, the amplifier 45a, It is transmitted to each customer on route a.
Also, there is no reflection at the point that is switched to the terminating resistor r _a. That is, the quality of the downstream signal of the network system divided upstream is maintained.

  The upstream signal from the customer is input from the path b, and is input to the photoelectric converter (O / E) 51 through the amplifier (Amp) 45b and the equalizer (EQ) 44b. Then, it is converted into an optical signal by the photoelectric converter (O / E) 51 and transmitted to the central device through the optical fiber 25. That is, customers after the composite repeater amplifier 50 are directly connected to the central device through the optical fiber 25. That is, the conventional network system is divided into two to form a new network system. Each divided network system reduces the waiting time because the number of consumers is halved. In that sense, communication efficiency is improved.

Although upstream network system is divided by removing the attenuator (ATT) 43 b, and a 75Ω termination hands resistor r _b on its location. Therefore, there is no reflection there. Therefore, the quality of the upstream signal of the network system divided upstream is also maintained. Needless to say, if the photoelectric conversion unit 59 is removed and a conventional automatic gain control device (AGC) 49 and attenuators 43a and 43b are installed, a conventional system is obtained.
Further, since the composite relay amplifier 50 also has the power pass filter 100, the power from the power supply device 90 can be sent to the outside. That can be handled equally well with conventional bidirectional relay amplifier 40B _n with respect to current.
In other words, in preparation for the future increase in consumers, if a composite relay amplifier 50 to which such an optical fiber can be easily connected is provided in advance in the network system, the network system can be instantly converted into an optical fiber when the demand increases. can do. That is, it becomes a useful relay device that is extremely convenient in industry.

(Second embodiment)
The first embodiment is an example in which the conventional network system is divided by the photoelectric converter unit 59 in both the upstream and downstream directions. However, the down direction uses a wide band of 70 MHz to 770 MHz. Therefore, for example, even if access is concentrated, the communication efficiency in the downlink direction does not greatly decrease. On the contrary, the upstream direction is a band of 10 MHz to 55 MHz, and the unused band is further used. Therefore, when access is concentrated, the communication efficiency may decrease. The present embodiment is an example for dealing with the above problem. In other words, this is an example in which the downstream direction is a conventional coaxial cable system and only the upstream direction is an optical fiber system. That is, this is an example in which a new network system divided only in the upstream direction is formed.

  FIG. 4 shows a composite relay amplifier 60 that divides only in the upstream direction. In this configuration, the terminal connection of the attenuator (ATT) 43a and the equalizer (EQ) 44a on the path a side of the composite relay amplifier 50 (FIG. 3) of the first embodiment is omitted. With this configuration, for example, the downstream signal from the central device is demultiplexed into the path a by the demultiplexer filter 42 as before, and passes through the attenuator (ATT) 43a, equalizer (EQ) 44a, amplifier 45a, etc. Sent. On the other hand, the upstream signal from the consumer after the photoelectric conversion unit 59 is demultiplexed into the path b by the downstream demultiplexing filter 42 and input to the photoelectric converter 51 through the amplifier 45b and the equalizer (EQ) 44b. Then, it is converted into an optical signal by the photoelectric converter 51 and transmitted to the central device via the optical fiber 25. That is, only the upstream signal is divided into two systems. Therefore, even if data access is concentrated in the upstream direction, there is no waiting as in the prior art. That is, upstream communication efficiency can be improved.

(Third embodiment)
The first and second embodiments are examples in which the input / output of the bidirectional coaxial amplifier is switched from the coaxial cable system to the optical fiber system only by attaching the photoelectric conversion unit to a predetermined terminal. The present embodiment is an example in which a changeover switch device is provided, and the changeover switch is operated by mounting a photoelectric converter to switch from a coaxial cable system to an optical fiber system. This embodiment is an example in which only a photoelectric converter is newly connected to a terminal using a conventional automatic gain control device (AGC). With this configuration, the number of terminals T can be reduced.

A composite relay amplifier 50 used in this embodiment is shown in FIG. The composite relay amplifier 50 of this embodiment is characterized by a bidirectional relay amplifier 40B _n (FIG. 2), a photoelectric converter (O / E) 51 connected to the optical fiber 25, a terminal T, and changeover switch devices 52 and 53. And termination resistors r _a and r _b .
The change-over switch devices 52 and 53 are, for example, push-type mechanical switches, and both switch the switch to the terminal p side when the photoelectric converter (O / E) 51 is attached to the terminal T. is there. Thereby, for example, the downstream signal transmitted from the central device through the optical fiber 25 is converted into an electric signal by the photoelectric converter (O / E) 51 and is sent to each consumer by the changeover switch device 52 and the amplifier 45a, that is, the path a. Sent. Incidentally, at this time, the upstream side of the switch of the switch device 52 is likewise switched switched to the terminal p side 75Ω termination resistors r _a. That is, there is no reflection there. Therefore, the quality of the downstream signal of the network system divided upstream is maintained.

  The upstream signal from the customer is input from the path b, and input to the photoelectric converter (O / E) 51 through the amplifier 45b, the terminal q of the changeover switch device 53, and the terminal T. Then, it is converted into an optical signal by the photoelectric converter (O / E) 51 and transmitted to the central device through the optical fiber 25. That is, customers after the composite repeater amplifier 50 are directly connected to the central device through the optical fiber 25. That is, the conventional network system is divided into two to form a new network system. Each divided network system reduces the waiting time because the number of consumers is halved. In that sense, communication efficiency is improved.

Note that, in the switching of the changeover switch device 53, the terminal p side has a 75Ω termination hands resistor r _b. Therefore, even if the changeover switch device 53 is switched to the p side, there is no reflection there. Therefore, the quality of the upstream signal of the network system divided upstream is also maintained. Needless to say, if the photoelectric converter 51 is removed, the changeover switch devices 52 and 53 are both switched to the terminal q side, resulting in a conventional system. Further, since the composite relay amplifier 50 also has the power pass filter 100, the power from the power supply device 90 can be sent to the outside. That can be handled equally well with conventional bidirectional relay amplifier 40B _n with respect to current.
That is, if the composite repeater amplifier 50 to which such an optical fiber can be easily connected is provided in advance in the network system, the network system can be rapidly converted into an optical fiber in response to an increase in demand.

(Fourth embodiment)
In the third embodiment, the conventional network system is divided by the photoelectric converter (E / O) 51 in both the upstream direction and the downstream direction. The present embodiment is an example in which optical fiber connection is performed only in the upstream direction, as in the second embodiment. That is, in this example, a photoelectric converter (E / O) 61 is employed instead of the photoelectric converter (E / O) 51, and a new network system in which only the upstream direction is divided is formed.

FIG. 6 shows a composite relay amplifier 60 that divides only in the upstream direction. In this configuration, the changeover switch device 52 of the composite relay amplifier 50 of the third embodiment is omitted, and a photoelectric converter (E / O) 61 that converts only in the upstream direction is used instead of the photoelectric converter (E / O) 51. This is the configuration adopted. Note that the housing 110 is omitted in the composite relay amplifier 60 of FIG.
With this configuration, for example, the downstream signal from the central device is demultiplexed to the path a by the demultiplexer filter 42 as before, and passes through the attenuator (ATT) 43 _a , the equalizer (EQ) 44 _a , the amplifier 45 a and the like. Sent to home. On the other hand, the upstream signal from the consumer after the photoelectric converter 61 is demultiplexed into the path b by the downstream demultiplexing filter 42, and the amplifier 45b, the attenuator 43b, the changeover switch device 53 (terminal q), and the terminal T are connected. Then, it is input to the photoelectric converter 61. Then, it is converted into an optical signal by the photoelectric converter 61 and transmitted to the central device via the optical fiber 25. That is, only the upstream signal is divided into two systems. Therefore, even if data access is concentrated in the upstream direction, there is no waiting as in the prior art. That is, upstream communication efficiency can be improved.

  When the photoelectric converter 61 is mounted, the changeover switch device 53 is switched to the terminal p side in conjunction with it. Since a terminal resistance r of 75Ω is provided on the terminal p side, there is no reflection there. Therefore, the quality of the upstream signal of the network system divided upstream is maintained. Further, if the photoelectric converter 61 is removed, the changeover switch device 53 is switched to the terminal q side, which is equivalent to the conventional system. That is, if such a composite relay amplifier 60 is provided in the network system in advance, it is possible to quickly respond to an increase in demand in the upstream direction. In other words, it is possible to quickly make an optical fiber only in the upstream direction.

(Modification)
Although one embodiment representing the present invention has been described above, various other modifications are conceivable. For example, in the first embodiment, when switching to the optical fiber system, the automatic gain control device (AGC) 49 and the attenuators (ATT) 43a and 43b are removed, and the photoelectric converter unit 59 and the terminating resistors r _a and r _b are removed. The terminal was connected. However, as shown in FIG. 7, an automatic gain control device (AGC) 49 may be provided on a substrate 59, and the substrate 59 may be connected to a conventional circuit by a terminal T. Incidentally, 59 means a unit containing a circuit together with a circuit board. Therefore, the unit 59 is detached from the amplifier housing. When the optical fiber connection is used, the substrate 59 (unit 59) is removed, and the substrate 59A is mounted as shown in FIG. The substrate 59A is also a unit incorporating a substrate and a circuit mounted thereon. Substrate 59A is previously provided substrate photoelectric converter 51, an automatic gain controller (AGC) 49a and the terminating resistor r _a, a r _b, as shown. If this substrate 59A (unit) is mounted, it can be easily switched between the coaxial cable system and the optical fiber system by one attachment / detachment. The operation and effect are equivalent to those of the first embodiment. It can also be configured in this way. In the following description, the board is also used as a unit.

Further, the terminal connection of the photoelectric converter unit 59A of FIG. 8 may be modified as shown in FIG. That is, the photoelectric converter 51 and the amplifiers 45a and 45b may be directly connected without using the attenuators 43a and 43b and the equalizers (EQ) 44a and 44b.
Furthermore, it can be modified as shown in FIG. That is, as shown in FIG. 10, the upstream side demultiplexing filter 42 and the automatic gain control device (AGC) 49 are provided on one board 59B, and the board can be removed by a plurality of terminals T. In the case of optical fiber connection, the photoelectric conversion unit 59C may be terminal-connected as shown in FIG. Similar effects can be achieved.

  Further, for example, in the third embodiment, the photoelectric converter (E / O) 51 is provided adjacent to the automatic gain control device (AGC) 49. However, as shown in FIG. 12, the automatic gain control device (AGC) ) A photoelectric converter (O / E) 51 may be provided in the space 55 after 49 is removed. That is, the photoelectric converter 51 may be attached to the terminal T exposed in the space 55 after the automatic gain control device (AGC) 49 is removed. Since space is saved, the composite relay amplifier 50 can be reduced in size. At this time, the amplifier manually controls the amplification factor. It can also be configured in this way.

  In the third embodiment, the change-over switch devices 52 and 53 are switched to the terminal p side in conjunction with the mounting of the photoelectric converter (E / O) 51. An operator may manually switch the changeover switch. Has the same effect. Similarly to the other examples, the terminals may be switched by simply attaching or detaching the board (unit) to / from the terminals.

  In the first embodiment, the CATV network system has been described in the form of a multidrop network, but other forms may be used. For example, a tree-type network system may be used. If various kinds of bidirectional relay amplifiers used there are replaced with the composite relay amplifier 50 of the present invention, the subsequent customers are connected to the central apparatus by new optical fibers. The form of the network does not matter.

  In the first embodiment, the network system is divided by replacing any of the relay amplifiers in the network system with a composite relay amplifier. However, the composite relay amplifier may be used to extend the network system. Good. When extending the system, the composite relay amplifier of the present invention may be provided at the end of the coaxial cable of the network system. In general, if the network system is extended, the number of consumers increases and the communication efficiency decreases. However, if the composite repeater amplifier of the present invention is provided at the final stage of the coaxial cable, newer optical fibers will be used by the subsequent customers. Connected directly to the device. That is, there is no increase in waiting time due to an increase in consumers. Therefore, a network system that does not reduce communication efficiency can be obtained.

10 ... central unit 20 and 25 ... optical fiber 30 ... customer 40A ... photoelectric bidirectional repeater amplifier 40B _n, B _m ... way relaying amplifier 45a, 45b ... amplifiers 49, 49a ... automatic gain control device 50 ... composite relay amplifier 51 ... photoelectric converter 55 ... space 59,59A, 59C ... photoelectric conversion unit 60 ... composite relay amplifier 61 ... photoelectric converter 52, 53 ... changeover switch 100 ... power pass filter T ... terminal r, r _a, r _b ... terminating resistor

Claims (1)

A signal is transmitted from the central device of the CATV station in the downstream direction of each consumer at the end, and the signal is transmitted from each customer in the upstream direction of the central device. A bidirectional relay amplifier,
A first demultiplexing filter provided on the central device side;
A second demultiplexing filter provided on the customer side;
A first attenuator provided between the first demultiplexing filter and the second demultiplexing filter, connected to the downstream terminal of the first demultiplexing filter, and a first equalizer connected to the first attenuator And a downstream amplifier that amplifies the downstream signal,
An upstream amplifier that amplifies an upstream signal, a second equalizer that equalizes an output signal of the upstream amplifier, and a second equalizer are provided between the first branching filter and the second branching filter. A bidirectional repeater amplifier comprising a first attenuator and a second attenuator detachably attached to the upstream terminal of the first demultiplexing filter,
The second attenuator is detached from the first terminal and the upstream terminal, a termination resistor is attached to the upstream terminal and the ground terminal, an output signal of the second equalizer is input, and this output signal is converted into an optical signal. A photoelectric conversion unit for converting to a free space in the bidirectional relay amplifier housing;
An optical fiber that transmits an optical signal converted by the photoelectric conversion unit to the central device side is connected to an output end of the photoelectric conversion,
A composite bidirectional relay amplifier characterized in that a downstream signal is an electrical signal, an upstream output signal is an optical signal, and the electrical signal and the optical signal are composited.

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