JP2585838B2 - High frequency relay amplifier with transmission frequency band switching function - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency relay amplifier suitable for a high-frequency electric signal transmission device using a coaxial cable.

[Conventional technology]

Conventionally, as a high-frequency electric signal transmission line using a coaxial cable, a coaxial transmission line in CATV is best known (for example, Ohm's "New Media Technology Series CA").
TV ”edited by the Institute of Electronics and Communication Engineers, supervised by Hiroshi Miyagawa).

FIG. 2 shows a configuration example of a coaxial transmission line in a general CATV. In the figure, high-frequency signals such as video and data transmitted from the head-end device 21 are transmitted to a plurality of terminals 25 via a coaxial cable 22, a main line distributor 23, a high-frequency relay amplifier 1, a drop-in branching device 24, and the like. Transmitted.

The high-frequency relay amplifier 1 has a main line output terminal 12 for amplifying and outputting an input signal from the main line input terminal 11 toward the next-stage high-frequency relay amplifier 1 and a branch terminal 13 for amplifying and outputting the signal toward the terminal 25. This is the most important transmission line device having a function of compensating for a high-frequency signal transmission loss of a coaxial cable.

The transmission frequency band of the conventional coaxial transmission line is determined by the transmission frequency performance of the high-frequency relay amplifier 1.

[Problems to be solved by the invention]

A conventional device of this type is configured as shown in FIG. 3, and the transmission frequency band of the high-frequency relay amplifier 1 is determined by the transmission frequency performance of the downstream amplifier circuits 2-3 and the upstream amplifier circuit 4, and When trying to change the transmission frequency band of the transmission line, there is a problem that the high-frequency relay amplifier 1 itself must be replaced.

On the other hand, the transmission frequency band in the CATV coaxial transmission line is the fourth
As shown in the example of the figure, there are various types. FIG.
FIG. 3D shows an example of narrowband one-way use, and FIG. 4D shows an example of limited-bandwidth bidirectional use exclusively used for data communication and the like.

Here, if only the narrow-band type shown in FIGS. 4 (b) to (d) is to be used for the time being, it is uneconomical to construct a wide-band type coaxial transmission line shown in FIG. 4 (a). Once a narrow-band coaxial transmission line has been constructed, there has been a demand for a method of transmitting a broadband-type high-frequency signal without remodeling the transmission line.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a high-frequency relay amplifier with a transmission frequency band switching function configured to easily change a transmission frequency band in view of the above points.

[Means for Solving the Problems] To achieve the above object, the present invention provides a wideband signal (for example, a signal of 10 to 450 MHz shown in FIG. 4A) or a narrowband signal (for example, 30 to 30 shown in Fig. 4 (b)
0 MHz signal), a bidirectional transmission type high frequency relay amplifier (1: see FIG. 7), wherein a first line is connected between a main line input terminal (11) and a main line output terminal (12). The switching means (14), the downstream trunk direction amplification means (2) having narrow band amplification characteristics, and the second switching means (8, 15) are connected in cascade, and are inputted to the trunk line input terminal (11). Connection means for supplying the downstream trunk signal from the first switching means (14) directly to the second switching means (8, 15) without passing through the downstream trunk direction amplifying means (2). A first signal transmission unit, the main line output terminal (12) and the main line input terminal (11)
And an upstream amplifying means (4) having a narrow band amplification characteristic is connected between them and an upstream signal to be inputted to the upstream amplifying means (4) is directly transmitted without passing through the upstream amplifying means (4). The second signal transmission unit including the third switching means (16) for supplying the signal to the main line input terminal (11) on the upstream side, and the downstream signal supplied from the plurality of branch terminals (13) to the outside are Output from the down-branch direction amplifying means (3) for amplifying a narrow-band signal obtained via the down-trunk direction amplifying means (2) and the second switching means (8, 15); The signal transmitted in the upstream direction from the branch terminal (13) is input to the upstream amplification unit (4) via the mixing unit (9) provided on the input side of the upstream amplification unit (4). 3 signal transmission unit.

[Action]

In the present invention, by providing the switching circuit as described above, the transmission frequency band in the trunk direction can be switched.

〔Example〕

 Hereinafter, the present invention will be described in detail based on examples.

FIG. 1 is a block diagram showing one embodiment of the present invention.
An example of application to a bidirectional transmission type high frequency relay amplifier will be described. In the figure, the downstream high-frequency signal from the main line input terminal 11 passes through the demultiplexer 5, the switching circuit 14, the downstream main direction amplifying circuit 2, the branching device 8, the switching circuit 15, and the demultiplexer 6, The downstream high-frequency signal output to the main line output terminal 12 and branched by the branch unit 8 is output to the branch terminal 13 via the switching circuit 15, the downstream branch direction amplification circuit 3, the duplexer 7, and the distributor 10. Is done. The upstream high-frequency signals from the trunk output terminal 12 and the branch terminal 13 are similarly output to the trunk input terminal 11 via the upstream amplifier circuit 4 and the like.

As shown in FIGS. 4 (b) to 4 (d), an arbitrary narrow band frequency signal transmission performance is assigned to the downstream trunk direction amplifier circuit 2, the downstream branch direction amplifier circuit 3, and the upward direction amplifier circuit 4. ~ 16, main line input terminal 11 and main line output terminal 12
A function of transmitting the narrow-band frequency signal in both directions of a trunk line between the trunk line and a branch direction between the trunk line input terminal 11 and the branch terminal 13;
In the main line direction, the function of transmitting a wideband frequency signal as shown in the example of FIG. 4A can be switched.

With the switching circuit of the high-frequency relay amplifier configured as described above, the transmission frequency band in the trunk line direction can be switched as shown in FIG. Here, FIG. 3A shows a case where a narrowband frequency signal is transmitted in both directions of a trunk line and a branching direction, and FIG. 3B shows a case where a wideband frequency signal is transmitted in a trunk line direction and narrowband in a branching direction. This is a case where a band frequency signal is transmitted.

FIG. 6 shows an example in which a wideband frequency signal can be transmitted to a narrowband frequency signal transmission coaxial transmission line constructed using the high-frequency relay amplifier 1 with a switching function. In the figure, the high-frequency relay amplifier with switching function is shown in FIG.
Since the broadband frequency signal passes in the trunk direction, the coaxial cable 22 is placed at an appropriate position.
By inserting a wide-band high-frequency relay amplifier for transmitting a wide-band frequency signal, transmission of a wide-band frequency signal from the amplifier to the wide-band terminal 32 becomes possible. Further, since the transmission frequency band to the narrowband terminal 25 connected to the branch terminal side of the high-frequency relay amplifier 1 with the switching function is invariable, the wiring to the terminal does not need to be changed.

The switching circuits 14 to 16 shown in FIG. 1 can be easily realized by using a high-frequency switch or a plug-in connector.

Further, the simplest configuration in which a specific narrow-band frequency transmission performance is assigned to the downstream main-line amplifier circuit 2, the downstream branch-direction amplifier circuit 3, and the upstream amplifier circuit 4 in FIG. The transmission frequency band of the high-frequency relay amplifier itself can be made selectable by switching a plurality of amplification circuits mounted inside the high-frequency relay amplifier, or by replacing the unit. Effective for strategic progress.

FIG. 7 is a block diagram more specifically showing the high-frequency relay amplifier shown in FIG. In the figure, the switching circuit 14
The high-frequency changeover switches SW1 to SW3 are used as the changers within the range of ~ 16. When the changeover switches SW1 to SW3 are connected to J1, the state is as shown in FIG. 5A, and when the switches are connected to J2, the state is as shown in FIG. 5B.

That is, in the state shown in FIG. 5 (a), the signal input to the main line input terminal passes through the amplifier circuit regardless of whether it is output to the main line output terminal or the branch terminal, so that both of them are narrow band type. Transmission path.

In the state shown in FIG. 5 (b), when the signal input to the main line input terminal is output to the main line output terminal, the signal does not pass through the amplifier circuit, so that even if the amplifier circuit is assigned the narrow band frequency transmission performance. A wideband signal can be transmitted to the main line output terminal and transmitted to the next high-frequency relay amplifier as shown in FIG.

On the other hand, when the signal is output to the branch terminal, it passes through the amplifier circuit, so that it becomes a narrow-band transmission line as in the case of FIG. In other words, switching can be performed depending on whether it is necessary to transmit a broadband frequency signal to the next high-frequency relay amplifier in the trunk line direction.

Also, the band-pass filters 17 to 18 are shown in FIG.
When switching to the state, the broadband frequency signal passing in the trunk direction is inserted so as not to affect the branching direction, and the branching devices 19 to 20 input and output signals in the branching direction at the time of switching. It is inserted so that the level does not change significantly.

〔The invention's effect〕

As described above, the high-frequency relay amplifier according to the present invention is capable of switching the transmission frequency band in the main line direction. Therefore, in the field of a high-frequency signal transmission line using a coaxial cable such as a CATV, transmission of the transmission line is performed. This is effective when the frequency band is expanded stepwise.

Further, the high-frequency relay amplifier according to the present invention can be applied to a one-way transmission type high-frequency relay amplifier having no upstream amplification circuit. Further, the high-frequency relay amplifier according to the present invention has an advantage in that it does not need to be replaced or removed at the time of transition to wideband frequency signal transmission only by switching the switching circuit according to the application.

As a specific application example of the present invention, a transmission path of a limited transmission frequency band for data communication or the like is initially constructed, and a case where a video transmission or the like is added in the future, or a TV community reception facility in a difficult-to-sight area. The present invention can be applied to a case where a new video transmission is added using a narrow band transmission path (multi-channel transmission).

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a high-frequency relay amplifier to which the present invention is applied, FIG. 2 is a block diagram showing a configuration example of a coaxial transmission line in a general CATV, and FIG. FIG. 4 is a frequency array diagram showing an example of use of a transmission frequency band in a coaxial transmission line, and FIG. 5 is a switching state of a switching circuit included in a high-frequency relay amplifier to which the present invention is applied. FIG. 6 is a block diagram showing a configuration example of a coaxial transmission line at the time of wideband frequency signal transmission, and FIG. 7 is a block diagram showing a more specific configuration of the high-frequency relay amplifier shown in FIG. is there. DESCRIPTION OF SYMBOLS 1 ... High frequency relay amplifier, 2 ... Downstream trunk direction amplifier circuit 3, ... Downstream branch direction amplifier circuit, 4 ... Upstream amplifier circuit, 5 ... Divider, 6 ... Divider, 7 ... Duplexer, 8
…… Branch device, 9 …… Mixer, 10 …… Distributor, 11 …… Main line input terminal, 12 …… Main line output terminal, 13 …… Branch terminal, 14…
... Switching circuit, 15 ... Switching circuit, 16 ... Switching circuit.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshiaki Sakamoto, Inventor 1 Tayacho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Inside the Yokohama Works, Sumitomo Electric Industries, Ltd. (72) Inventor Hiroyuki Fudo 3-chome Nakanoshima, Kita-ku, Osaka-shi, Osaka No. 22 Kansai Electric Power Co., Inc. (72) Noboru Fukae, Inventor No. 3-3-3 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture (72) Inventor Tadashi Nishiyama, 3-chome Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture No. 22 Kansai Electric Power Co., Inc. (72) Inventor Shunichi Nakamura 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd. (56) References Jiyo Sho 62-151244 (JP, U)

Claims (3)

(57) [Claims] 1. A high-frequency relay amplifier of a bidirectional transmission type for selectively relaying a wideband signal or a narrowband signal, comprising: first switching means between a main line input terminal and a main line output terminal; Downstream main direction amplification means having characteristics,
The second switching means is connected in cascade with the second switching means, and the downstream switching signal input to the trunk input terminal is directly transmitted from the first switching means to the second switching means without passing through the downstream main direction amplifying means. A first signal transmission unit having connection means for supplying the signal to the upstream amplification means having narrow band amplification characteristics between the trunk output terminal and the trunk input terminal. A second signal transmission unit having third switching means for directly supplying an upstream signal to be input to the upstream main line input terminal without passing through the upstream amplification means; Is output from the downstream branch direction amplifying means for amplifying a narrow band signal obtained via the downstream trunk direction amplifying means and the second switching means, and from the plurality of branch terminals. Upward direction And a third signal transmission unit for inputting the signal to be transmitted to the upstream amplification unit via a mixing unit provided on the input side of the upstream amplification unit. With high frequency relay amplifier. 2. A high-frequency relay amplifier with a transmission frequency band switching function according to claim 1, wherein said switching means has a switching switch structure or a plug-in connector structure. 3. The switching of the transmission frequency bands of the downstream trunk direction amplifying means, the downstream branch direction amplifying means and the upstream direction amplifying means to a plurality of amplifying circuits mounted inside the high-frequency relay amplifier, or a unit. 2. The high-frequency relay amplifier with transmission frequency band switching function according to claim 1, wherein the high-frequency relay amplifier can be selected by a method such as exchange.