KR100272765B1 - Return path controllable tap off - Google Patents

Abstract

The present invention relates to a signal branch that can control an uplink signal. The uplink signal control branch according to the present invention is a signal branch for branching a downward signal in the channel direction of the field from the head end and focusing the upstream signal from the channel of the field to the head end according to the state of the upstream signal. A data communication unit for receiving information, a control unit for outputting a signal for controlling the channel of the field according to the output signal of the data communication unit, and the input and output unit for controlling the channel of the field in accordance with the output signal of the control unit.

Description

Upward signal control tap-off

The present invention relates to a diverter for branching signals installed in a transmission network constituting a cable broadcasting (CATV) facility, and in particular, by incorporating a module capable of preventing the occurrence of upward noise, which can block the generation of uplink signal noise in the entire transmission network. It relates to an upward signal control branch.

CATV, which is currently used, is a multi-channel broadcast that transmits video, audio, and sound to subscribers using wired information and communication facilities. In addition, as an information channel for the viewer to arbitrarily select a variety of information is a professional local information broadcast for viewers in a certain area.

CATV consists of transmission system, cable and relay amplifier of wired broadcasting station equipped with transmission equipment such as head end where all signals are transmitted to transmission path and all signals are concentrated in bidirectional system. It consists of a transmission system that constitutes a facility and a subscriber system that includes indoor facilities such as a distributor and a converter. The difference between CATV and other broadcasting communication facilities is the facility up to the transmission line and the subscriber line. That is, the basic network configuration constituting the transmission system to the transmission system and the subscriber is a tree and branch network, in which the transmission line is branched like a branch. This is because the transmission system of the head end is extremely efficient when transmitting the same signal to multiple subscribers.

Similarly in the bidirectional CATV system, the downlink signal is transmitted from the head end side to the subscriber side and the uplink signal is transmitted from the subscriber side to the head end through the network structure of the resin network. The transmission of the uplink signal and the downlink signal, of course, goes through a distribution module, and the distribution module is configured with a branch to perform a function of branching a signal.

1 illustrates an example of a conceptual diagram of upward noise generation.

The branching device in the uplink noise generating conceptual diagram shown in FIG. 1 is composed of an input terminal, an output terminal, and a plurality of branch tap offs. This conventional tap-off is a passive device that only branches the input signal to the subscriber, and does not have any blocking function against external noise.

For example, in the downlink signal from the head end side to the subscriber side, one signal is branched and transmitted to the subscriber side, so that the signal reaches the same level of signal-to-noise ratio (S / N) even at the final stage, thereby greatly affecting the noise. Do not receive. On the other hand, in the case of the upstream signal from the subscriber side to the head end side, the noise due to the electromagnetic waves generated from the terminal equipment such as the subscriber-side bidirectional converter and the surrounding home appliances, etc. increases toward the head end side, and the effect of the noise is repeated. It becomes bigger. That is, since the severe noise in a particular branch affects the entire network together with the signal from the other subscriber side through combining into the next stage, there is a problem that the entire system becomes unstable as a result.

Therefore, measures are required to cut off the upstream signal in advance or to attenuate the noise.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the above-described conventional branching system, and by adding a module for monitoring and controlling the upstream signal to the conventional branching system, it is possible to immediately prevent the occurrence of the upstream noise and improve the transmission quality of the transmission network. To provide a turn-off.

In addition to the function of branching a signal, the branching apparatus of the present invention receives a control information of a channel in the form of dual tone multi frequency (DTMF) and decodes the data communication unit, and determines a state of a corresponding channel according to the decoded command to control the control signal. And an input / output unit for performing an operation on a corresponding channel according to the control signal output from the controller.

Preferably, the input / output unit is further provided with an input terminal for a test signal so as to confirm the normal operation of the control unit at the head end side, and to perform the switch switching operation to block, attenuate, and short-circuit the respective channels according to the control signal. It is composed.

1 is a conceptual diagram of upward noise generation;

2 is a block diagram of a tap off transponder including an uplink signal control module according to an embodiment of the present invention;

3 is a flowchart illustrating an operation of an uplink signal control branch according to an embodiment of the present invention.

4A and 4B are diagrams illustrating channel states and corresponding switch states of each state of a corresponding channel under control of the controller 50 according to an embodiment of the present invention, as examples (channels 1 and 2). drawing.

5a to 5c show examples of tap-offs each having a different number of taps.

<Explanation of symbols for the main parts of the drawings>

10: return path controller

20: return path analyzer

30: return path switch

40: data communication unit

50: control unit

60: input / output unit

70: RF switch module

80: coupling module

90: diplexer

Embodiments of the present invention will be described below with reference to the drawings.

2 illustrates a configuration of a tap-off transponder including an uplink signal control module according to an embodiment of the present invention. The tap off responder shown in FIG. 2 is divided into a head end and a field, and the head end has a return path controller 10, a return path analyzer 20, and a return path switch 30. The signal diverter configured between the head end and the site includes a data communication unit 40, a control unit 50, an input / output unit 60, and the like that receive DTMF signals from the return path controller. In addition, the input / output unit 60 includes an RF switch module 70, a coupling module 80, a diplexer 90, and the like.

3 is a flowchart illustrating an operation of an uplink signal control branch according to an embodiment of the present invention. An operation of the uplink signal control branch according to the flowchart shown in FIG. 3 will be described below.

The uplink signal channel in the CATV system according to the present embodiment is monitored, tracked, and controlled through the return path controller 10 and the return path analyzer 20. Through steps a1 to a4, a signal for a noisy channel is received and the channel is checked for a case where it is determined that the switching operation for the received channel is appropriate. At this time, if it is determined that the switching operation for the channel is not suitable, the flow advances to step a5 to wait for a command.

Then, in step a6, the return path controller 10 sends a switching command for the corresponding channel, that is, a DTMF signal, to the data communication unit 40. Here, the data communication unit 40 is a one-way DTMF decoder which decodes the received signal and outputs it to the control unit 50.

Then, in step a7, the controller 50 controls the corresponding channel according to the input signal. Control of the corresponding channel performed by the controller 50 may include a short circuit if the influence of noise is negligible, attenuation circuit if the noise affects the signal but not large, and the influence of noise is too large. If the corresponding channel as well as other channels have a high impact, it includes switching to the blocking circuit.

4A and 4B are diagrams illustrating channel states and corresponding switch states of each state of a corresponding channel under control of the controller 50 according to an embodiment of the present invention as an example (channels 1 and 2). . As shown in Figs. 4A and 4B, for example, in the case where the state of channel 1 is in the cutoff state, the switch 1 (SW1) is connected to b, and the switch 5 (SW5), switch 6 (SW6) and switch 7 (SW7) are off, and switch 2 (SW2) is connected to the b contact as in line 1 of FIG. 4B.

In addition, the process of confirming the normal operation of the RF switch module 70 by the return path controller 10 may transmit a frequency signal, for example, a signal of 6 MHz, that is not used by other equipment of the CATV system to the RF switch module 70. It is substantially performed by detecting the output signal with the return path analyzer 20 after inputting as a test signal.

In the embodiment according to the present invention, the RF switch module 70 typically uses a frequency band of 5 to 50 MHz, but in case of using a double diffused MOS (DMOS) as the switching element to perform high-speed switching. Up to MHz.

5A to 5C respectively show diverters with different numbers of taps. In FIG. 5A, the number of taps is two, four in FIG. 5B, and eight in FIG. 5C. In all three cases, an input port to which an AC / RF signal is input and an AC / RF signal are output. The output port is provided.

In addition to the function of branching a signal, the uplink signal control branch in the CATV system according to the present invention tracks and monitors the state and noise of a channel to provide an alarm state and a corresponding action command for the corresponding channel. By additionally providing a data communication unit for decoding, a control unit for controlling the RF switch in accordance with the output signal of the data communication unit, and an input / output unit 60 for performing a switching function of the corresponding channel according to a command from the control unit. The stability of the CATV system can be improved.

In addition, since the uplink control signal diverter according to the present invention uses the DTMF scheme, it is possible not only to use the components used in the general technical field as it is, and also because it does not require a separate encoder for switching the corresponding channel, The volume can be reduced.

Claims (5)

In a signal diverter for branching a downward signal in the field channel direction from the head end, and focusing the upward signal from the channel in the field to the head end, A data communication unit for receiving information about the uplink signal; A control unit which outputs a signal for controlling the channel according to an output signal of the data communication unit; An input / output unit for controlling the channel according to an output signal of the controller Signal diverter comprising a. The method of claim 1, wherein the head end, A return path analyzer for checking the normal operation of the input / output unit, and A return path controller connected to the return path analyzer for sending an output signal according to the check to the data communication unit Signal diverter comprising a. The signal diverter of claim 1, wherein the data communication unit is a unidirectional decoder using a dual tone multi frequency (DTMF) scheme. 2. The apparatus of claim 1, wherein the input / output unit receives a test signal having a frequency band different from that of the uplink signal and the downlink signal so as to check whether the input / output unit is normally operated at the head end side. Signal diverter further comprises a test signal input. 2. The signal diverter according to claim 1, wherein the control of the subscriber-side channel of the input / output unit includes switching control to a short state, attenuation state, and a cutoff state.