JP3281501B2 - Amplifying device for adjusting main line amplifier of CATV system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adjusting amplifying apparatus used for adjusting a main amplifier inserted in a transmission line of a CATV system. In particular, the present invention is an amplification device that can be used in an adjustment method that can replace an equalization unit of a main line amplifier, a transmission characteristic unit such as a pseudo line unit, an amplification unit, and a power supply unit without stopping a wave.

[0002]

2. Description of the Related Art Conventionally, CAT has been used as a device for preventing a wave interruption.
2. Description of the Related Art In V relay amplifiers, there is known a device in which a unit incorporating an amplifier can be detached without stopping transmission of a high-frequency signal to a downstream side of a transmission line. This device switches the contacts of the relay in conjunction with the attachment and detachment of the unit, so that when the unit is disconnected from the transmission line, the input terminal and the output terminal are connected by a bypass circuit by the operation of the relay. is there.

[0003]

However, in this type of device, when the unit is mounted, the drive current flowing to the relay coil is bypassed to ground, and when the unit is detached, the bypass circuit to ground is cut off. As a result, a high-frequency signal is bypassed from an input terminal to an output terminal by driving current flowing through the relay coil and switching the relay contact. As a result of using such mechanical contacts, there is a problem that the durability of the device is not good. In addition, there is also a problem that the video is stopped only for a moment because the switching speed is slow because of mechanical switching of the contacts. Further, such a device has a problem that the manufacturing cost is high.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a unit constituting a main line amplifier inserted into a transmission line of a CATV system, that is, an equalizing unit and a pseudo line unit. And the like, so that the transmission characteristic unit, the main amplification unit, the branch amplification unit, and the power supply unit can be replaced without interruption.

[0005]

According to a first aspect of the present invention, there is provided a trunk amplifier to be inserted in a transmission path of a CATV system, wherein the first amplifier is inserted in a main path. A branching device and an information signal transmitting terminal connected to a branch end of the first branching device for transmitting an information signal to a transmission line ;
Pair and , if there is a first switch, the downstream side
Te, min of the second splitter and its second splitter that is inserted into the main passage
Of the set of input monitor terminal connected to 岐端 monitor the RF input signal input from the transmission path, at least one
A set of one branch unit and one terminal, and a downstream side when there is a second branch unit on the main road, and a case where there is no second branch unit
A main amplifying unit that is inserted downstream of the first branch unit and amplifies the high-frequency signal of the main path, a third branch unit that is inserted into the main path downstream of the main amplifier unit, and a third branch unit. Branch
An output monitor terminal connected to the end for monitoring a high-frequency output signal output to the transmission line, a fourth branch unit inserted downstream of the main amplifying unit on the main path, and connected to a branch end of the fourth branch unit; For adjusting a trunk amplifier for a CATV system having a branch amplification unit, a fifth branch unit connected to an output terminal of the branch amplification unit, and a branch monitor terminal connected to a branch end of the fifth branch unit. In the adjusting amplifying device used, an input terminal connected to an information signal sending terminal or an input monitor terminal, an adjusting amplifying unit for amplifying a high frequency signal input from the input terminal, and a high frequency signal amplified by the adjusting amplifying unit. branched and branched divider for branching distribution, a first output terminal for outputting one of the signals branched distributed by the branch distributor to the output monitor terminal, by the branch distributor The arranged the other signal, characterized in that a second output terminal for outputting the branch monitor terminal.

The level of the two signals output from the adjusting amplifier is adjusted so that the signal level at the output terminal or the branch terminal of the main amplifier does not change between when the signal is bypassed and when the signal is not bypassed. Has been adjusted. That is, it is desirable to insert an attenuator between the branch distributor and the output monitor terminal and between the branch distributor and the branch monitor terminal to adjust each signal level. Further, an amplifier capable of variably setting the level of its two outputs may be used as an amplifier capable of branching and distributing the adjustment amplification unit. Further, a transmission characteristic adjusting unit having transmission characteristics substantially equal to characteristics of a transmission characteristic unit such as an equalizing unit and a pseudo line unit inserted in the main path of the main amplifier may be provided. In this case, even during the adjustment, the signal transmission characteristics are equalized on the downstream side of the main amplifier, and the image quality can be improved without the signal level being saturated.

[0007]

[Operation and Effect of the Invention] 1. The input terminal of the replacement amplifying device of the main amplifying unit is connected to the information signal sending terminal or the input monitor terminal, and one output signal of the adjusting amplifying device is connected to the branch monitor terminal and the other. Is input to the output monitor terminal. In this state, the branch amplification unit is removed, a switch is provided at the output of the branch amplification unit and the switch is opened, or if the switch is held in the closed state by power supply, the branch amplification unit is connected to the branch amplification unit. power through or to stop, entry of the fifth divider
An operation of setting the impedance viewed from the force end to the upstream side to be substantially infinite (hereinafter referred to as infinity) is performed. This operation is not output signals from the branch amplifier unit, a high-frequency signal amplified by the adjustment amplifier branch monitor terminal, a fifth splitter branch end, the fifth splitter, the output of the fifth divider The data is transmitted to the branch road via the end . As a result,
Wave interruption to the branch road due to the above operation is prevented.

On the other hand, on the main path, the high-frequency signal amplified by the main amplification unit passes through the fourth branch unit and the third branch unit,
The signal is output downstream from the output terminal of the trunk relay amplifier. At this time, since the third coupler has a large reverse coupling loss from the branch terminal to the output terminal , the signal amplified by the adjusting amplifier is not transmitted to the output terminal of the trunk relay amplifier. Next, when the main amplifying unit is removed, no signal is output from the main amplifying unit. However, the reverse coupling loss of the third branch unit is reduced, and the high-frequency signal amplified by the adjustment amplifying device becomes the third amplifying device.
Through the output end of the splitter from the branch end, it is transmitted to the output terminal of the trunk line amplifier. Therefore, the high-frequency signal is transmitted to the downstream side of the main trunk relay amplifier, so that the interruption does not occur. In this state, the main relay augmentation unit is replaced, and then, if the branching amplification unit is attached to the original, or if there is a switch at the output of the branching amplification unit, the switch is closed or the switch is opened and closed. If it is linked to power supply, supply power to the branch amplification unit,
The impedance when the upstream side of the transmission line is viewed from the input end of the fifth branch is used as the original line impedance, so that the transmission state is normal. That is, the signal amplified by the main amplification unit is branched, further amplified by the branch amplification unit, and output to the branch road side. Next, the adjustment amplifying device is removed, and the adjustment ends. Since the process is executed in such a procedure, a wave stop on the downstream side of the main road and the branch road is prevented.

2. The input terminal of the replacement amplifying device of the power supply unit is connected to the information signal transmitting terminal or the input monitor terminal, one output signal of the adjusting amplifying device is output to the branch monitor terminal, and the other output signal is output. Input to the monitor terminal.

In this state, the branch amplification unit is removed, a switch is provided at the output of the branch amplification unit and the switch is opened, or if the switch is kept closed by power supply, the branch amplification unit is used. An operation of stopping the power supply to the unit or making the impedance looking upstream from the input end of the fifth branching device infinite is performed. This operation is not output signals from the branch amplifier unit, a high-frequency signal amplified by the adjustment amplifier branch monitor terminal, a fifth splitter branch end, the fifth splitter, the output of the fifth divider The data is transmitted to the branch road via the end . As a result, the interruption of the branch road due to the above operation is prevented.

On the main path, the high-frequency signal amplified by the main amplifying unit passes through the fourth branch unit and the third branch unit, and is output from the output terminal of the trunk relay amplifier to the downstream side. At this time, since the third coupler has a large reverse coupling loss from the branch terminal to the output terminal , the signal amplified by the adjusting amplifier is not transmitted to the output terminal of the trunk relay amplifier. Next, the main amplifier unit is removed, or a switch is provided at the output of the main amplifier unit and the switch is opened, or if the switch is kept closed by power supply, power is supplied to the main amplifier unit. Is stopped, or the operation of setting the impedance as viewed upstream from the input end of the third branch unit to infinity is performed. By this operation, no signal is output from the main amplification unit, but from the branch end of the third branch unit.
Since the reverse coupling loss to the output terminal is reduced to about the branch loss, the high-frequency signal amplified by the branch amplification unit is output from the output monitor terminal, the branch terminal of the third branch device, the third branch device, and the output terminal of the third branch device. To the downstream side of the main path.

Therefore, even if the main amplifying unit and the branch amplifying unit are removed, the high-frequency signal is transmitted to the downstream side of the main transmission line and the branch transmission line of the main trunk relay amplifier, so that no wave stop occurs. In this state, the power supply unit is replaced. At this time, when the power supply unit is removed, power is supplied to the adjustment amplification device by using another power supply or by using power superimposed on the transmission path.

The operation of setting the impedance looking upstream from the input end of the fifth branch unit to infinity is performed by the input of the third branch unit.
Prior to the operation of setting the impedance at the upstream side from the end to infinity, the signal from the output monitor terminal is prevented from sneaking into the branch road side, so that the image quality at the time of adjustment is improved. However, the operation of setting the impedance to infinity may be performed in the reverse order unless a slight decrease in image quality is considered.

Next, when the main amplifying unit is originally attached, or when there is a switch on the output of the main amplifying unit, the switch is closed, and when the opening and closing of the switch is linked to power supply, By feeding power to the main amplifying unit, the impedance seen from the input end of the third branch to the upstream side of the transmission line is used as the original line impedance, so that the main amplifying unit amplifies the downstream side of the main line. The transmitted signal is transmitted.

The switch is closed when the branching amplification unit is originally attached or when there is a switch at the output of the branching amplification unit. For example, power is supplied to the amplification unit, and the impedance when the upstream side of the transmission path is viewed from the input end of the fifth branch is used as the original line impedance, so that the transmission state is normal. That is, the signal amplified by the main amplification unit is branched, further amplified by the branch amplification unit, and output to the branch road side. Next, the adjustment amplifying device is removed, and the adjustment ends. Since the process is executed in such a procedure, a wave stop on the downstream side of the main road and the branch road is prevented.

The operation of returning the impedance seen from the input end of the third branch unit to the line impedance to the line impedance is the fifth operation.
If prior to the operation of returning the impedance seen from the input end of the branching unit to the line impedance to the line impedance, the branching amplification unit is ready to receive the signal amplified and branched by the main amplification unit. Desirable because waves are prevented. However, the order of the above-mentioned return may be reversed if the temporary stop of the branch road is not a problem. Of course, the main road does not cause a wave stop in either procedure.

3. Replacement of Transmission Characteristics Unit The input terminal of the amplifying device for adjustment is connected to the information signal transmission terminal, and a transmission characteristics unit such as an equalization unit and a pseudo line unit is provided between the first branch unit and the main amplifier. It is intended for inserted mains amplifiers. The procedure for replacing the transmission characteristic unit, the detour route of the signal, and the reason why the interruption does not occur are described in 2.
Is exactly the same as the replacement of the power supply unit.

4. Replacement of Branch Amplification Unit In the replacement procedure of the main amplification unit in 1., the branch amplification unit may be replaced. Of course, if the replacement of the main amplification unit is not necessary, there is no replacement procedure. Also, the first output
There is no need to connect the terminal to the output monitor terminal.

5. Others When an attenuator is inserted between the branch distributor and the output monitor terminal or between the branch distributor and the branch monitor terminal, the output of the amplifying device for adjustment is 2 It is easy to keep the signal levels at the output terminal or the branch terminal of the main amplifier from changing when the signal is detoured and when the signal is not detoured. Also, the level can be easily adjusted by using an amplifier that can variably set the level of its two outputs as the amplifier that can branch and distribute the adjustment amplification unit. Further, a transmission characteristic adjusting unit having transmission characteristics substantially equal to characteristics of a transmission characteristic unit such as an equalizing unit and a pseudo line unit inserted in the main path of the main amplifier may be provided. In this case, even during the adjustment, the signal transmission characteristics are equalized on the downstream side of the main amplifier, and the image quality can be improved without the signal level being saturated.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on specific embodiments.
I will tell. FIG. 1 is a block diagram showing the configuration of a bidirectional mains amplifier.
FIG. Input terminal 2 of mains amplifier,Output terminal 39
Are connected to the transmission lines 1a and 1b, respectively. High
The main path through which the high-frequency signal flows
Along the direction, input terminal 2, first splitter 3, splitter 4, etc.
Unit 5, pseudo line unit 6, second branch unit 7,
Width unit 8,4th branch9, third branching device 10, duplexer
11,Output terminal 39Is provided. In this embodiment,
Means that the equalization unit 5 and the pseudo line unit 6 have transmission characteristics
Corresponds to a knit. In general, the transmission characteristic unit is
Arbitrary circuit unit for adjusting transmission characteristics such as frequency characteristics
In addition, a filter, a duplexer, and the like correspond. or,
The transmission characteristic unit is an input side and an output side of the amplification unit 8.
All circuits that adjust the transmission characteristics inserted in all
Including.

Next, as a branch path of the high-frequency signal, the first
The status signal transmission terminal 21 which is an information signal transmission terminal to the branching device 3, the input monitor terminal 22 to the second branching device 7, the fourth
The branch relay unit 40 is connected to the branch device 9, and the output monitor terminal 23 is connected to the third branch device 10, respectively.

On the other hand, in the direction in which the upstream high-frequency signal flows,
Branching filter 11, branching device 51, branching device 52, amplification unit 5
3, a pseudo line unit 54, an equalization unit 55, a splitter 56, and a duplexer 4 are provided. And the branching device 52
Are connected to the input monitor terminal 61, the branch unit 56 is connected to the output monitor terminal 63, and the branch unit 51 is connected to the branch relay unit 40.

The branch relay unit 40 includes a branch amplification unit 41 for amplifying a downstream high-frequency signal, a branch amplification unit 42 for amplifying an upstream high-frequency signal, and a duplexer 43. The output signal of the demultiplexer 43 is sequentially transmitted to the fifth branching device 4
4. The signal propagated to the distributor 45 and divided into two by the distributor 45 is further divided into two by the distributors 46 and 47, respectively. As a result, signals branched from the branch terminals BR1 to BR4 are transmitted. The fifth branch unit 44 is connected to the branch monitor terminal 24.

A power supply unit 12 for supplying power to the amplification units 8 and 53 and the branch amplification units 41 and 42 is provided. The main line amplifier is configured as described above. In repairing the main amplifier, a problem mainly arises that the downstream high-frequency signal stops. Therefore, in this embodiment, when the equalizing unit 5, the pseudo line unit 6, and the amplifying unit 8 inserted in the downstream main path are replaced, the downstream high-frequency signal is not stopped.

1. As shown in FIGS. 1 and 3, the replacement amplifying device 31 of the main amplifying unit includes an input terminal E1, an adjusting amplifying unit 311, a splitter 33, a first
Attenuator 101, second attenuator 102, first output terminal O1,
And a second output terminal O2. When replacing the main amplifying unit, as shown in FIG. 1, the input terminal E1 of the adjusting amplifying device 31 is connected to the input monitor terminal 22, the first output terminal O1 is connected to the output monitor terminal 23,
The second output terminal O2 is connected to the branch monitor terminal 24. The gain of the adjustment amplification unit 311, the first attenuator 101, the second
The amount of attenuation of the attenuator 102 depends on whether the signal is not bypassed or the signal is bypassed.
4 and the output terminal 39 are set to values that do not cause fluctuations in the signal level.

As described above, when the adjustment amplifying device 31 is connected, the downstream high-frequency signal input from the transmission line 1 a is partially branched by the second branching unit 7. Then, the branched high-frequency signal is amplified by the adjustment / amplification unit 311, and is then branched by the branch unit 33 into two. Then, one of the signals is output via the first attenuator 101 and the first output terminal O1, the output monitor terminal 23, the third splitter 10, the duplexer 11, and the output terminal 3.
9 is output to the second attenuator 102 and the second signal.
Via the output terminal O2, the branch monitor terminal 24, the fifth branch unit 44, the distributors 45, 46, 47, the branch terminals BR1 to BR
Output to R4 .

However, the transmission loss from the branch end of the fifth branch unit 44 to the output end is as large as the reverse coupling loss of 40 dB.
Further, the transmission loss from the branch end to the output end of the third branch unit 10 is as large as the reverse coupling loss of 40 dB. Therefore, the branch high-frequency signal amplified by the adjustment amplification device 31 is not substantially output to the branch path side and the transmission path 1b side. In this state, the high-frequency signal is amplified by the main amplifying unit 8 and transmitted to the transmission line 1b, and a part of the high-frequency signal is branched by the fourth splitter 9, and the branched signal is separated by the branching and amplifying unit 41. The signal is amplified, divided into four by the distributor 45 and the distributors 46 and 47, and transmitted to the branch. Therefore, the suspension of the downstream high-frequency signal does not occur on the main road and the branch road.

Next, in the above state, the branch amplification unit 41 is removed. At the moment of removal, the fifth branch 4
Since the impedance when the branch amplification unit 41 side is viewed from the input terminal of the fourth branch unit 4 becomes infinite, the transmission loss from the branch terminal of the fifth branch unit 44 to the output terminal is approximately 20 dB, which is approximately the same as the branch loss. . Accordingly, in this state, the downstream high-frequency signal is transmitted to the output terminal of the fifth branch unit 44 via the adjusting amplifier 31. Therefore, the downstream high-frequency signal can propagate to the downstream side of the branch path, and no wave stop occurs. The operation of setting the impedance to infinity is performed by opening the switch when the output circuit of the branching amplification unit 41 is provided with a switch, and by closing the switch when power is supplied. Can also be achieved by stopping the power supply to the branching amplification unit 41.

Next, the main amplification unit 8 is removed. At the moment of removal, the impedance from the input end of the third splitter 10 to the main amplifying unit 8 side becomes infinite, so that the transmission loss from the split end of the third splitter 10 to the output end is substantially equal to the branch loss. Of 20 dB. Therefore, in this state, the downstream high-frequency signal is supplied to the third branch 10
To the output end . Therefore, the downstream high-frequency signal can propagate to the downstream side of the main path, and no wave stop occurs.

Next, a new main amplification unit 8 is installed. At this moment, the reverse coupling loss of the third branching device 10 becomes large, the signal does not detour to the main path side, and the signal transmitted to the downstream side of the main path becomes a signal amplified by the main amplification unit 8. Further, the output signal of the main amplification unit 8 is partially branched, and the branch signal is ready to be input to the branch amplification unit 41. This state is the same as the state before the main amplifying unit 8 is removed with respect to the main path, so that the interruption of the down signal on the main path does not occur. Similarly, since the output of the amplifying device for adjustment 31 is given to the branch path, the interruption of the branch path does not occur.

Next, the branching amplification unit 41 is attached as before, and power is supplied to this unit. At that moment the fifth
The reverse coupling loss of the branching device 44 increases, and the signal does not detour to the branch road side.
The signal amplified by 1 is output. In this way, the signal transmission route is in a normal state on both the main road side and the branch road side. Next, the adjustment amplifying device 31 is removed from the input monitor terminal 22, the branch monitor terminal 24, and the output monitor terminal 23. In this way, the downstream high-frequency signal can be returned to the initial state without stopping the main road and the branch road.

The above operation of setting the impedance to the original line impedance is performed by closing the switch when a switch is provided in the output circuit of the branching amplifying unit 41. If it is held, it can also be achieved by starting power supply to the branching amplification unit 41.

2. Replacement of Branch Amplification Unit When replacing a branch amplification unit, only the branch amplification unit 41 is removed and only the unit is replaced in the connection of FIG. With the branching amplification unit 41 removed, the high-frequency signal is sent to the branching path to the adjustment amplification device 31.
Is supplied via The main path is supplied via a main amplification unit 8. Note that it is not necessary to connect the first output terminal O1 of the adjusting amplifying device 31 to the output monitor terminal 23 because it is not necessary to return the signal to the main path.

Also, as shown in FIG. 2, the input terminal of the adjusting amplifier 31 is connected to the status signal transmitting terminal 21 so that the adjusting amplifier 31 has an overall characteristic of the equalizing unit 5 and the pseudo line unit 6. The main amplification unit 8 can be replaced by the same procedure as described above, except that the transmission characteristic adjustment unit 312 having the same characteristics is provided and the other components are the same as those in FIG. In this case, even when the signal is bypassed during the adjustment, the signal is equalized, so that it is possible to prevent a decrease in video quality during the adjustment.

3. Replacement of Power Supply Unit The power supply unit 12 can be replaced by connecting as shown in FIG. As described in 2., the input of the fifth branch 44
An operation of setting the impedance when viewing the branch amplification unit 41 side from the power end to infinity is performed. Next, the third branch 1
The operation of setting the impedance when viewing the main amplification unit 8 from the input terminal of 0 to infinity is executed. This operation is performed in the same manner as in the case of the branch amplification unit 41, except that the main amplification unit 8 is removed, and when a switch is provided in the output circuit of the main amplification unit 8, this switch is opened, and the switch is closed. When the state is maintained by power supply, it can also be achieved by stopping power supply to the main amplification unit 8.

As described above, at the moment when the operation of setting the impedance when viewing the main amplification unit 8 from the input end of the third branch unit 10 to infinity is performed, the reverse coupling loss of the third branch unit 10 becomes substantially equal to the branch loss. Is about 20 dB, so the adjusting amplifier 3
The signal amplified by 1 is output to the downstream side of the main path via the output monitor terminal 23 and the third branch 10. Therefore, in this state, there is no wave stop on the downstream side of the branch road and the main road.

Next, the power supply unit 12 is replaced. Then, in the reverse order of the above, that is, in the order of the third branch unit 10 and the fifth branch unit 44, an operation of returning the impedance viewed from the input end to the transmission line side to the original line impedance is executed. This operation is performed by attaching the main amplifying unit 8 and closing the switch when the output circuit of the main amplifying unit 8 is provided with a switch, and when the closed state of the switch is maintained by power supply. Can also be achieved by starting power supply to the main amplification unit 8. 2.
As described in the above, at the moment when the impedance when the transmission path side is viewed from the input end of the third splitter 10 is restored to the line impedance, the signal detour to the main path is stopped, and the signal amplified by the main amplification unit 8 is stopped. Is transmitted downstream of the main path. After the impedance as seen from the input end of the fifth branch 44 to the transmission line side is restored to the line impedance,
As described in 2., the signal transmission route is in the original state.

In this manner, the power supply unit 12 can be replaced without stopping the main road and the branch road.

The fifth branch unit 44 and the third branch unit 10
As described above, the operation of setting the impedance on the upstream side of the transmission line from the output end to infinity and the operation of returning the line impedance to the original line impedance are not necessarily performed in the above order.

Further, as shown in FIG.
By connecting the input terminal 2 to the status signal sending terminal 21, the power supply unit 12 can be replaced in accordance with the above procedure.

4. Replacement of Transmission Characteristic Unit As shown in FIG. 2, by connecting the amplifying device 32 for adjustment, the transmission characteristic units such as the equivalent unit 5 and the pseudo line unit 6 can be exchanged. That is, the adjusting amplifying device 32
Is connected to the status signal sending terminal 21, and the first output terminal O1 and the second output terminal O2 of the adjusting amplifying device 32 are the same as those in FIG.

The operation procedure is the same as that of the power supply unit 12 described in 3.
Is exactly the same as the exchange. That is, instead of the power supply unit 12, the equivalent unit 5 or the pseudo line unit 6 may be replaced. The detour route of the signal and the reason why the wave does not stop are as described in 3.

The adjusting amplifying device excluding the transmission characteristic adjusting unit 312 can be configured as shown in FIGS. 4 and 5 in addition to the configuration shown in FIG. As shown in FIG. 4, the splitter 33 of FIG.
The same configuration can be obtained by using a distributor 34 instead of Further, as shown in FIG. 5, the above-described level adjustment may be performed by separating the input signal into two, amplifying the input signal with an amplifier having an independent gain, and outputting two signals. .

The adjusting amplifying device configured as described above outputs two signals each having a predetermined signal level, and outputs one output signal to the branch monitor terminal 24 and the other output signal to the output monitor terminal 23. As you type
The output terminal 39 is switched between a signal detour state and a signal detour state.
In addition, the level can be adjusted so as not to change the signal levels of the branch terminals BR1 to BR4.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main amplifier used in an adjustment amplifying device and an adjustment method using the device according to a specific embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a main amplifier used in an adjustment amplifying apparatus and an adjustment method using the same according to another specific embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of an adjustment amplifying device according to a specific embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of an adjustment amplifying device according to another specific embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of an adjustment amplifying device according to another specific example of the present invention.

[Explanation of symbols]

 1a, 1b: Transmission path 3: First branch unit 5: Equivalent unit 6: Pseudo-line unit 7: Second branch unit 8: Main amplification unit 9: Fourth branch unit 10: Third branch unit 21: Status signal sending terminal Reference numeral 22: input monitor terminal 23: output monitor terminal 24: branch monitor terminal 31, 32: amplifying device for adjustment 33: branch device 311, 312: adjusting and amplifying unit 321, 322: transmission characteristic adjusting unit

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/00 H04N 7/10 H04N ^7/ 14-7/173 H04N ^7/ 20-7/22

Claims (4)

(57) [Claims] 1. A main line amplifier inserted into a transmission line of a CATV system, wherein the main line amplifier is connected to a first branch unit inserted into a main line and a branch end of the first branch unit, and transmits an information signal to the transmission line. A pair with an information signal transmitting terminal for performing
In the case where there is a branching device, an input monitor connected downstream of the second branching device and a branch end of the second branching device and monitoring a high-frequency input signal input from the transmission line , as a downstream side of the branching device. of the set of terminals, a set of the one of the terminals at least one splitter, the second splitter in the main path
If there is, the downstream side , if there is no second branching device
A main amplifying unit that is inserted downstream of the first branch unit and amplifies the high-frequency signal of the main path; a third branch unit that is inserted into a main path downstream of the main amplification unit;
An output monitor terminal connected to the branch end of the branch unit for monitoring a high-frequency output signal output to the transmission line; a fourth branch unit inserted downstream of the main amplification unit in the main path; CATV system having a branch amplification unit connected to a branch end of a branch unit, a fifth branch unit connected to an output terminal of the branch amplification unit, and a branch monitor terminal connected to a branch end of the fifth branch unit. An adjustment amplifying device used for adjusting the main trunk amplifier, an input terminal connected to the information signal transmission terminal or the input monitor terminal, an adjustment amplification unit that amplifies a high-frequency signal input from the input terminal, A branch distributor for branching and distributing the high-frequency signal amplified by the adjusting and amplifying unit, and outputting one of the signals branched and distributed by the branch distributor to the output monitor terminal; And a second output terminal for outputting the other signal branched and distributed by the branch distributor to the branch monitor terminal. 2. The adjustment amplification unit of the adjustment amplification device has an attenuator between the branch distributor and the first output terminal and between the branch distributor and the second output terminal. The adjustment amplifying device according to claim 1, wherein: 3. The adjusting amplifying device according to claim 1, wherein the adjusting amplifying unit of the adjusting amplifying device is an amplifier having a branch distribution function capable of changing a signal level. 4. The transmission characteristic of an equalizing unit, a pseudo line unit, or the like inserted in the main path of the main line amplifier when the input terminal is connected to the information signal transmitting terminal. 2. The transmission characteristic adjusting unit according to claim 1, further comprising a transmission characteristic adjusting unit having a transmission characteristic substantially equal to a total characteristic of the transmission characteristic unit for adjusting the transmission characteristic.
3. The adjusting amplifying device according to claim 1.