KR20030082016A - Line terminator for very high-speed digital subscriber line - Google Patents

Abstract

PURPOSE: A line terminator for a VDSL(Very high-speed Digital Subscriber Line) is provided to terminate a line, for preventing phenomenon in which an RF(Radio Frequency) signal is reflected in a termination portion of the line when the RF signal is transmitted through the line. CONSTITUTION: An impedance matching unit(10) identically matches the impedance of the termination of a bridge line with the impedance of a line, for preventing phenomenon that the performance of a VDSL modem and a high-speed DSL using 10MHz or more frequency bands is degraded by the bridge line. A line terminator is embodied as one-pole type HPF(High Pass Filter), for using an HPF type line termination method which does not have an influence on a telephone used in the same line and for minimizing the change of an input and output impedance of a VDSL system.

Description

Line terminator for very high-speed digital subscriber line}

The present invention belongs to a technique for terminating a line in order to eliminate the phenomenon that the high frequency signal is reflected at the end of the line when the signal is transmitted through the line in the field of signal transmission technology. RF Terminator is mainly used to reduce the reflected wave generated at the end when high frequency signal is transmitted through coaxial cable. It is used to terminate the line terminator with the same value as the impedance of the line. Systems that transmit signals using coaxial cable have high frequency and do not contain DC components. Therefore, the conventional RF terminator has an impedance value of 50 ohms or 75 ohms and has only a resistance component.

With the activation of high speed internet, VDSL technology, which can transmit data of several tens of Mbps, is being developed, starting with ADSL technology that can transmit data of several Mbps through a telephone line. Increasing the data rate requires increasing the frequency band of the signal used. Currently, VDSL's frequency band uses more than 10MHz and many models use higher frequencies.

Since telephone plugs must be installed in each room in the home, the home telephone network is inevitably connected in a bridge form, and in most homes, bridge lines of several meters or more are connected in parallel. VDSL equipment using the 10MHz band or more bands can be significantly degraded by bridge lines of several meters to several tens of meters with open line ends. At this time, termination of the bridge line, which causes the line termination to be problematic, can be greatly assisted in the transmission performance of the VDSL system. However, the termination of the resistive component, as in the conventional RF terminator, can improve the performance of the VDSL system, but it cannot be used on the line.

The telephone line in the home requires the installation of telephone plugs in each room, so that several strands of bridge lines are connected to the same telephone line, and the specific frequency is reflected by the bridge with the open end. The transmission capacity is greatly degraded. VDSL modems with broadband over 10 MHz can be greatly affected by bridge lines with open ends of several meters to tens of meters. In this case, it is intended to provide a means for terminating bridge terminations with the same impedance as the line. . In addition, since the existing RF terminator has only a resistive component, this method has the side effect of being unable to use the telephone on the same line. Therefore, the present invention is intended to implement a terminator that can also improve the performance of the VDSL without affecting the telephone usage.

Most homes are equipped with two-line (four-line) telephone lines, of which any can be used for VDSL, allowing for the optional termination of the required lines, as well as regular telephone jacks and RJ-11 telephones. It wanted to use all jacks, and to have plug and jack functions at the line terminator at the same time so that the phone can be connected to the port using the line terminator, and to be used anywhere regardless of the type of telephone plug installed in the home. In addition, the present invention was implemented in a high-pass filter method so that the line terminator does not interfere with the use of the telephone in the same line, at this time to minimize the effect of the high-pass filter terminator on the input and output characteristic impedance of the VDSL system.

1 is a circuit diagram of the present invention, 30 represents a telephone jack, 40 represents a telephone plug, and 50 and 60 represent RJ-11 connectors.

Figure 2 is a diagram showing the appearance (Case) for the present invention 100 is the top, 200 is the bottom, 300 is the bottom side.

3 is a diagram illustrating a state in which a VDSL (VDSL) modem and a Digital Subscriber Line Access Multiplexor (DSLAM) are connected to a telephone line, and a line terminator is connected to the bridge line end.

The present invention, the impedance matching unit 10, the line selector 20, the jack 30 for a general telephone, the plug 40 for a telephone, RJ-11 connectors (50, 60), the case (100, 200, 300) It consists of

Impedance matching unit 10 serves to terminate the line termination of the high-speed digital subscriber line using the VDSL or more (10MHz or more) frequency band according to the characteristic impedance of the line. When data is transmitted by connecting VDSL modem and Digital Subscriber Line Access Multiplexor (DSLAM) across two strands of telephone line, both ends of line are impedance matched to the line impedance, so no reflected wave occurs at the end of the line. Within the maximum allowable distance, most of the performances such as link connection and transmission speed appear normally. However, almost all home telephone lines are wired with the same line in each room so that there is always a bridge as shown in Fig. 4, so if the VDSL system is connected to both ends as shown in Figs. There remains a telephone line bridge (4 in FIG. 3) that remains open. In FIG. 3, 1 is a DSLAM, 2 is a VDSL modem, 4 is a telephone line bridge, and 3 is a line terminator. When the termination is open, that is, when there is no line terminator 3, a specific frequency is reflected depending on the length of the bridge line, and this reflected wave causes a significant degradation of transmission loss between the VDSL modem and the DSLAM for that frequency. Among the VDSL methods, the Discrete Multi-Tone (DMT) modulation method automatically disables the frequency corresponding to the band when the loss characteristic of a specific frequency is bad, but is less affected by the bridge. Most VDSL systems adopt Quadrature Amplitude Modulation (QAM), which is a single-carrier modulation method that is considered to have excellent overall performance. In the case of the QAM scheme, the transmission performance is greatly affected when the transmission loss of a specific frequency is severely degraded. Therefore, the application of the line terminator 3 which terminates the bridge whose terminal is open with the same impedance as the characteristic impedance of the line as shown in FIG. 3 greatly improves the performance of the VDSL system in the case where the performance is degraded due to the bridge problem. do. However, simply terminating the telephone line impedance at the bridge end with a resistive component is very helpful for the VDSL system, but it is not possible to use the telephone on the same line. Therefore, the line terminator 10 invented in the present invention has an impedance for the frequency band used in the telephone in order to terminate the line termination with the characteristic impedance of the line for the VDSL system while having little effect on the telephone usage. In the frequency band of the VDSL system, a high-pass filter is implemented so that the characteristic impedance of the line matches the line impedance value. At this time, the high-pass filter was implemented as a 1-pole type to minimize the effect on the input and output impedance of the VDSL system.

The telephone line that enters the home is generally 4 wires, and the upper 1, 2 lines and the lower 3, 4 lines are used as a pair of four telephone plugs. When you install a VDSL modem, you will use lines 1, 2, or 3, 4 of your home telephone line, if necessary. Therefore, it is necessary to be able to terminate the termination of the line used by the VDSL system among the 1st, 2nd and 3rd and 4th lines. Accordingly, the line selectors 20 and 202 provide a means for selectively terminating the telephone lines 1, 2 and 3, 4 as necessary.

Desk phone jacks (30, 201) provide a means to connect directly to a telephone plug installed on the wall of your home, and telephone plugs (40, 101) allow you to connect telephone jacks directly to This prevents the inconvenience of connecting the phone from that port. RJ-11 (50, 301, 60, 302) also provides a means to easily adapt to RJ-11 type telephone plugs installed in modern buildings.

Cases 100, 200, and 300 are equipped with an impedance matching unit 10, a line selector 20, a jack for a general telephone 30, a plug for a regular telephone 40, and an RJ-11 connector (50, 60). It provides a means for the appearance (Case) is shown in FIG. In FIG. 2, 100 is a top surface, 200 is a bottom surface, and 300 is a bottom side surface.

Therefore, the present invention can be applied to both old and new telephone plugs, and can selectively terminate one of the four-prong telephone lines, and can improve the performance of the VDSL system without affecting the telephone use on the same line. It provides a means to terminate the termination of a bridge line.

When a high-speed data transmission system using a wideband frequency such as VDSL attempts to transmit data to a domestic telephone network, a transmission loss characteristic at a specific frequency is greatly deteriorated due to bridged wiring of the domestic telephone network. Application of the present invention when the performance is not improved significantly improves the transmission characteristics of the VDSL system by improving the transmission characteristics for the frequency.

In addition, the present invention can be applied to the case where the VDSL modem and the telephone are used on the same telephone line because the termination of the bridge line has little effect on the telephone use on the same line. It also allows the VDSL system to be selectively terminated regardless of which one, two or three or four lines of telephone lines are used, and includes both standard telephone jacks and RJ-11 connectors to accommodate all types of telephone plugs. In addition, the jack and plug function are combined so that there is no inconvenience in using the telephone even when the line terminator is applied.

In addition, the present invention will greatly help to solve the performance degradation problem caused by the bridge in the case of other high-speed data subscriber line using a frequency band in addition to the VDSL system.

Claims (2)

In order to improve this phenomenon, high speed digital subscriber lines using VDSL modems and higher frequency bands have the same impedance matching as the end of the bridge line. Implementing a one-pole high-pass filter to minimize changes in the input / output impedance of the VDSL system during this process, including the high-pass filter termination method that does not affect the telephone. In the method of claim 1, in the implementation of the line terminator, the switch can be used to selectively terminate any one of the two telephone lines in the home, and the ordinary telephone plug and jack are put together so as not to interfere with the telephone jack connection. , 2 RJ-11 connectors built-in to accommodate all telephone outlets.