JP3175402B2 - CATV repeater amplifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CATV repeater amplifier used in a CATV system.

[0002]

2. Description of the Related Art In recent years, a CATV system has a unit structure in which a circuit having one function is easily housed in a case so that a circuit having one function can be easily replaced. Further, a CATV repeater amplifier, which is mounted on one pedestal and has a structure in which units are connected to each other inside the pedestal, has become mainstream.
At the same time, in order to facilitate the work of adjusting the input / output characteristics of the CATV relay amplifier, a signal obtained by superimposing a plurality of different frequencies input / output via a coaxial cable is input to the input side of the amplifier composed of each unit or A monitor circuit for extracting the signal on the output side and outputting the same to a monitor, and a switch circuit for separating an intrusion point of the ingress noise superimposed in the upstream band have been provided.

Hereinafter, a conventional CAT will be described with reference to the drawings.
The V relay amplifier will be described. First, FIG. 2 shows a structural diagram of a relay amplifier. In FIG. 2, 33,
Reference numerals 34, 35 and 36 denote amplifier units, reference numerals 37 and 39 denote coaxial connectors, reference numeral 38 denotes a projection connection terminal.
Coaxial connectors 37 and 39 serving as input / output terminals for signals and a convex connection terminal 38 serving as a supply terminal for a power supply and the like are provided on the bottom surfaces of 3, 34, 35 and 36, respectively. Here, the amplifier unit 33 has a built-in circuit having one function of a relay amplifier, for example, an up-branch amplifier unit,
The signal is input from the coaxial connector 37 and the amplified signal is output from the coaxial connector 39.
8.

Reference numeral 40 denotes a pedestal, reference numerals 41 and 43 denote coaxial connector seats, and reference numeral 42 denotes a concave connection terminal. Coaxial connector seats 41 and 43 and a concave connection terminal 42 are provided above the pedestal 40 on the amplifier units 33, 34, 35 and 36. Each is provided in an opposing manner. Reference numeral 44 denotes an aluminum die-cast case. The amplifier units 33, 34, 35, 36 and the pedestal 40 are connected to each other via coaxial connectors 37, 39, the protruding connection terminals 38, the coaxial connector seats 41, 43, and the concave connection connector 42. It is built.

Next, FIG. 3 shows an upstream branch input monitor circuit of a CATV repeater amplifier, comprising the pedestal 40 and a upstream branch amplifier unit 33 having a function of detecting ingress noise.

In FIG. 3, reference numeral 1 denotes a first branch terminal, 2 denotes a third branch terminal, 3 denotes a first mixer, and a first branch terminal 1
The third branch terminal 2 is connected to the first mixer 3. Reference numeral 4 denotes a first branching filter, which comprises a first low-pass reactor 5 and a first high-pass reactor 6;
The common terminal of the mixer 3 is connected to the middle point of the first low-pass reactor 5 and the first high-pass reactor 6.

Reference numeral 7 denotes a second branch terminal, 8 denotes a fourth branch terminal, 9 denotes a second mixer , and the second branch terminal 7 and the fourth branch terminal 8 are connected to the second mixer 9 respectively. It is connected. Reference numeral 10 denotes a second branching filter, which is a second low-pass reactor 1
1, the second high-frequency reactor 12 and the second hybrid
The common terminal of the mixer 9 is connected to the middle point of the second low-pass reactor 11 and the second high-pass reactor 12.

Reference numeral 14 denotes a first coaxial connector seat, to which the first low-pass reactor 5 of the first branching filter 4 is connected.

Reference numeral 16 denotes a second coaxial connector seat to which the second low-pass reactor 11 of the second branch filter 10 is connected.

Next, reference numeral 20 denotes a first coaxial connector, reference numeral 21 denotes a second coaxial connector, and reference numeral 22 denotes a first switch for cutting off inflow noise from the first and third branch terminals 1 and 2. , 23 are second switches for blocking the ingress noise from the second and fourth branch terminals 7, 8, and 24 is a fourth switch.
In the mixer , the first coaxial connector 20 is connected to the first switch 2
2 to the fourth mixer 24 via a likewise the second coaxial connector 21 to the fourth mixer via a second switch 23 2
4 is connected.

29 is a directional coupler, 25 is an upstream amplifier,
26 is a variable attenuator, 27 is a third coaxial connector, and the common terminal of the fourth mixer 24 is connected to an upstream amplifier 25 via a directional coupler 29 and further to a fourth coaxial connector via a variable attenuator 26. 3 coaxial connector 27. Reference numeral 30 denotes a fixed attenuator, and 31 denotes a fourth coaxial connector. The branch terminal of the directional coupler 29 is connected to the fourth coaxial connector 31 via the fixed attenuator 30. 33. Reference numeral 28 denotes a third coaxial connector seat.

Reference numeral 32 denotes a fourth coaxial connector seat, and 19 denotes a monitor terminal.
Are configured in the base 40.

The operation of the upstream branch input monitor circuit configured as described above will be described below. First, the first
The signals input from the first branch terminal 1 and the third branch terminal 2 are mixed by a first mixer 3 and then applied to a first branching filter 4 to obtain a first low-pass reactor 5. Only the upstream band is extracted and supplied to the first coaxial connector seat 14. Similarly, the signals input from the second branch terminal 7 and the fourth branch terminal 8 are mixed by the second mixer 9 and then added to the second branching filter 10, and the second low-pass filter 10 Only the upstream band is extracted by the zone furnace wave 11 and supplied to the second coaxial connector seat 16.

Next, the pedestal 40 and the upstream branching amplifier unit 33 are connected to the first, second, third and fourth coaxial connector seats 14, 16, 28 and 32 and the first, second, third and third coaxial connector seats. 4, the upstream signal supplied to the first coaxial connector seat 14 is transmitted through the first coaxial connector 20 and the first switch 22 to the fourth coaxial connector 20, 21, 27, 31. The upstream signal supplied to the second mixer 24 and similarly to the second coaxial connector seat 16 is transmitted through the second coaxial connector 21 and the second switch 23 to the fourth mixer 2.
4 are mixed by a fourth mixer 24 and amplified by an upstream amplifier 25 via a directional coupler 29 and adjusted to a specified level by a variable attenuator 26. Is supplied to the third coaxial connector seat 28 through the coaxial connector 27 of the first embodiment.

The signal from the branch terminal of the directional coupler 29 is supplied to the fixed attenuator 30 by, for example,
The level is set so as to be 20 ± 1 dB, and output to the monitor terminal 19 via the fourth coaxial connector 31 and the fourth coaxial connector seat 32.

Here, for example, when the upstream data signal is disturbed by the inflow noise at the CATV center and communication becomes impossible, the cascaded relay amplifiers 33 provided in the upstream branch amplifier units 33 of the respective relay amplifiers. By shutting off the first or second switch 22, 23, it is possible to search for a noise entry path.

As described above, the ingress noise included in the upstream signals input from the first or third branch terminals 1 and 2 and the second or fourth branch terminals 7 and 8 is reflected in the upstream branch amplifier unit. 33, provided on each input side.
By shutting off the first and second switches 22 and 23, respectively, the intrusion route can be confirmed, and the upstream signal supplied via the first and second switches 22 and 23 can be mixed in the fourth mixing mode. after mixing in vessel 24 branches a part of the signal by the directional coupler 29, further fixed attenuator 3
By setting the level at 0, an upstream branch input signal can be output to the monitor terminal 19.

[0018]

However, in the above-described configuration, in order to confirm the operation of the upstream branch input monitor circuit, it is necessary to check the amount of monitor coupling after assembling the upstream branch amplifier unit on the base. No, in other words, the characteristics depend on both the upstream branching amplifier unit and the pedestal, so the confirmation work at the time of production / adjustment becomes very complicated, or the connection by the coaxial connector is required to connect the upstream branching amplifier unit and the pedestal. Four fittings and one fitting by the concavo-convex portion connection terminals are required, and there has been a problem that workability and mechanical reliability at the time of unit insertion and removal are deteriorated.

The present invention has been made in view of the above problems, and has as its object to provide an upstream branch input monitor circuit including a switch for blocking upstream inflow noise with a simple circuit configuration.

[0020]

In order to solve the above-mentioned problems, a CATV repeater amplifier according to the present invention transmits signals from two branch terminals provided on the left and right end faces of the repeater amplifier in the pedestal. After mixing using the first and second mixers on each side and extracting the upstream branch input signal in the first and second low-pass reactors, the first and second directional couplers are used. , A part of the signals from the first and second low-pass reactors is extracted, and the extracted up-branch input signals are mixed using a third mixer, and the level is adjusted by an attenuator. Thus, a configuration is provided in which the upstream branch input signal is output to the monitor terminal.

[0021]

According to the present invention, each of the signals input from the left and right end faces of the CATV repeater amplifier can be partially converted by using the directional coupler without the incorporation of the up-branch amplifier unit into the base. By taking out and further mixing with a mixer, it is possible to check the amount of coupling of the upstream branch monitor with only the pedestal alone irrespective of the ingress noise detection function, to improve workability during production and adjustment and to connect terminals The workability and mechanical reliability at the time of unit insertion / extraction can be improved by reducing the number.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An up-branch input monitor circuit of a CATV repeater amplifier according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an upstream branch input monitor circuit of a CATV repeater amplifier according to the present invention.
The first branch terminal 2 and the third branch terminals, 3 a first mixed
A coupler , 4 is a first branching filter, 5 is a first low-pass reactor, 6 is a first high-pass reactor, 7 is a second branch terminal, 8 is a fourth branch terminal, 9 is a second mixer , 10 is a second demultiplexing filter, 11 is a second low-pass reactor, 12 is a second high-pass reactor, 14 is a first coaxial connector seat, and 16 is a second coaxial connector seat. The second coaxial connector seat, 20 is the first coaxial connector, 21 is the second coaxial connector.
, 22 is a first switch, 23 is a second switch, 24 is a fourth mixer , 25 is an upstream amplifier, 2
6, a variable attenuator; 27, a third coaxial connector; 28, a third coaxial connector seat; 19, a monitor terminal;
The configuration is the same as that described above.

Reference numeral 13 denotes a first directional coupler, 15 denotes a second directional coupler, 17 denotes a third mixer, and 18 denotes a fixed attenuator. The output of the band reactor 5 is supplied to the first coaxial connector seat 14 via the first directional coupler 13, and the output of the second low band reactor 11 of the second branching filter 10 is also supplied to the first coaxial connector seat 14. It is connected to a second coaxial connector seat 16 via a second directional coupler 15. The branch terminal of the first directional coupler 13 and the branch terminal of the second directional coupler 15 are connected to a third mixer 17, and the common terminal is connected to a monitor terminal 19 via a fixed attenuator 18. Are connected, and the above is configured in the pedestal 40.

The operation of the upstream branch input monitor circuit configured as described above will be described below. First, the first
The signals input from the first branch terminal 1 and the third branch terminal 2 are mixed by a first mixer 3 and then applied to a first branching filter 4 to obtain a first low-pass reactor 5. , Only the upstream band is extracted, and the first band is extracted via the first directional coupler 13.
Is supplied to the coaxial connector seat 14. Similarly, signals input from the second branch terminal 7 and the fourth branch terminal 8 are:
After being mixed in the second mixer 9, it is added to the second branching filter 10, only the upstream band is extracted in the second low-pass reactor 11, and the second directional coupler 15 is removed. Through the second
Is supplied to the coaxial connector seat 16.

Next, the base 40 and the upstream branching amplifier unit 33 are connected to the first, second and third coaxial connector seats 14,
16, 28 and the first, second and third coaxial connectors 20,
21 and 27, the upstream signal supplied to the first coaxial connector seat 14 is transmitted to the first coaxial connector 2.
0, via a first switch 22 to a fourth mixer 24,
Similarly, the upstream signal supplied to the second coaxial connector seat 16 is transmitted to the second coaxial connector 21 and the second switch 2.
3 to the fourth mixer 24, respectively.
The signal mixed by the fourth mixer 24 is supplied to the upstream amplifier 2
After being amplified at 5 and adjusted to a prescribed level by the variable attenuator 26, it is supplied to the third coaxial connector seat 28 via the third coaxial connector 27.

The respective signals from the branch terminal of the first directional coupler 13 and the branch terminal of the second directional coupler 15 are mixed by a third mixer 17 and fixed attenuator 18 At, for example, the level is set so as to be −20 ± 1 dB with respect to the input, and the level is output to the monitor terminal 19.

Here, for example, when the upstream data signal is disturbed by the inflow noise at the CATV center and communication becomes impossible, the cascaded relay amplifiers 33 provided in the upstream branch amplifier units 33 of the respective relay amplifiers. By shutting off the first or second switch 22 or 23, it is possible to search for a noise entry path.

As described above, according to the present invention, each signal input from the left and right end faces of the CATV repeater amplifier can be converted into a signal using the directional coupler without incorporating the upstream branch amplifier unit in the base. By taking out a part and further mixing by a mixer, the amount of uplink branch monitor coupling can be confirmed only by the pedestal alone irrespective of the ingress noise detection function.

[0030]

As described above, according to the present invention, there is provided a CATV relay amplifier including an amplifier unit having a unit structure and a pedestal for mounting the amplifier unit.
Signals from two branch terminals provided on each of the left and right end surfaces of the CATV repeater amplifier are mixed on the respective sides in the pedestal using first and second mixers, and the first and second mixers are mixed. After extracting the up-branch input signal with the low-pass reactor described above, a part of the signal from the first and second low-pass reactors is extracted via the first and second directional couplers. Further, by adopting a configuration in which the upstream branch input signal extracted using the third mixer is mixed and the level is adjusted by the attenuator, the upstream branch input signal can be monitored without using the amplifier unit in the base. Output, and the characteristics of the amount of monitor connection of the device do not depend on the unit, so that it is possible to check the circuit operation of the pedestal alone, and to improve the workability during production and adjustment. Can be. Moreover, compared to a method in which signals from each branch terminal are mixed in the upstream branch amplifier unit and then output to the monitor terminal, the number of connection terminals between the unit and the pedestal can be reduced. The mechanical reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an upstream branch input monitor circuit of a CATV relay amplifier according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the structure of a CATV relay amplifier.

FIG. 3 is a circuit diagram of an upstream branch input monitor circuit of a conventional CATV repeater amplifier.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 1st branch terminal 2 3rd branch terminal 3 1st mixer 5 1st low-pass reactor 7 2nd branch terminal 8 4th branch terminal 9 2nd mixer 11 2nd low Lower furnace wave device 12 Second higher furnace wave device 13 First directional coupler 14 First coaxial connector seat 15 Second directional coupler 16 Second coaxial connector seat 17 Third mixer 18 Fixed attenuator 19 Monitor terminal 20 First coaxial connector 21 Second coaxial connector 22 First switch 23 Second switch 24 Fourth mixer 25 Up amplifier 26 Variable attenuator 27 Third coaxial connector 28 Third Coaxial connector seat

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04B 3/36 H04N 7/10

Claims (1)

(57) [Claims] An amplifier unit having a unit structure,
And a pedestal mounting the amplifier unit, the pedestal, and the first and second mixer for mixing the signal from the branch terminal arranged two by two, than the signal from the first and second mixer 1st and 2nd which take out an upstream branch input signal
And the low frequency furnace filter, and a third mixer for mixing After withdrawn part of the first and second signals from the low-frequency furnace filter through the first and second directional coupler And a monitor terminal to which an up-branch input signal from the third mixer is supplied after its level is adjusted by an attenuator.