KR100311150B1 - Apparatus for testing bit error of a telecommunication line - Google Patents

Abstract

The present invention relates to an apparatus for predictive testing of bit errors in digital subscriber lines. In the prior art, only the inductive noise caused by the power line is measured by using a phosometric filter. There is no noise measuring method and a use filter suitable for an actual integrated information network service or system characteristics. Therefore, there is a problem in evaluating the noise of the digital subscriber line, and the 'E filter' applied in foreign countries expresses the total noise sum included in the frequency band, and measures the spectral distribution of the noise to determine the influence of the noise size according to each frequency. Can't evaluate Accordingly, in the present invention, the noise spectrum of the digital subscriber line 14 can be measured to determine the allowable limit of noise corresponding to each frequency. Therefore, whenever various types of network termination apparatuses are used, referring to FIGS. 3 and 4, it is possible to easily determine whether a current digital subscriber network causes a bit error.

Description

Bit error test device for telecommunication line {APPARATUS FOR TESTING BIT ERROR OF A TELECOMMUNICATION LINE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to apparatus for testing bit errors of telecommunication lines, and more particularly, to apparatus for predicting and testing bit errors of digital subscriber lines.

1 is a block diagram showing a general connection between an Integrated Services Digital Network (ISDN) switch and an Integrated Services Digital Network telephone, wherein the Integrated Services Digital Network (2) and Integrated Services Digital telephone (6) are connected through a digital subscriber line. do. At this time, the comprehensive information network switch 2 is provided with a line terminator (LT) 4 and the integrated information network telephone 6 has a network terminator (NT) 8.

In the figure, the integrated information network service is provided through a metallic digital subscriber line consisting of two wire pairs. In other words, the line terminator 4 on the side of the integrated information network switch 2 and the network terminator 8 on the side of the integrated information network telephone 6 are directly connected through a digital subscriber line.

At this time, the line terminator 4 is defined as a functional group including transmission and reception functions for terminating one end of the line as an exchange facility. In addition, the network termination device 8 is defined as a functional group including a transmission and reception function for terminating one end of a line at the subscriber side.

In addition, the basic rate interface (BRI) of the integrated information communication network is composed of two B (information) channels having a transmission rate of 64 Kbps and one D (control) channel having a transmission rate of 16 Kbps.

In the case of evaluating noise in a conventional voice-grade analog subscriber line, noise generated mainly on a power line flows into a communication line, and such low frequency noise affects the human ear. Therefore, either a phosometric filter or a C-message filter is used.

Afterwards, as digital services such as general information and communication networks increased in the 1990s, the effects of noise began to appear as serious aspects such as bit error, speed drop, and communication interruption depending on the performance of the system.

Among these, the quality of service may vary depending on the performance of the network termination apparatus applied to the subscriber terminal. Therefore, electrical characteristics and performance tests are to be performed according to international standards or domestic standards. In addition, it is necessary to measure the noise generated in the digital subscriber line to determine whether the digital subscriber line can be applied to such a system. In this case, the response of the network termination device may vary depending on the frequency.

In this regard, when measuring the noise of the subscriber line, '50 kbit filter ', which was applied to data service in foreign countries, was used, but recently, the' E filter 'with a 3 dB frequency range of 1 kHz and 50 kHz was extended by slightly extending the frequency range. It is recommended to measure the noise of subscriber line of integrated telecommunication network service.

In Korea, it is only to measure the induced noise by the power line by using the phosometric filter, there is no noise measuring method and filter used for the actual integrated information network service or system characteristics. Therefore, there is a problem in evaluating the noise of the digital subscriber line, and the 'E filter' applied in foreign countries expresses the total noise sum included in the frequency band, and measures the spectral distribution of the noise to determine the influence of the noise size according to each frequency. Can't evaluate

The present invention has been made to solve the drawbacks of the prior art, which measures the noise spectrum of the subscriber line of the integrated information network to obtain a tolerance mask of noise corresponding to each frequency. It is an object of the present invention to provide a bit error test apparatus for a telecommunication line.

In order to achieve the above object, the present invention provides a bit error test apparatus for a telecommunication line including a network termination device connected to a digital subscriber line, comprising: a noise providing unit for providing noise to the digital subscriber line; As the reference signal is transmitted to the network termination device through the digital subscriber line, the network signal is reflected by the network termination device and returned through the digital subscriber line. The reference signal is received by mixing the noise provided from the noise provider. And a bit error display unit for detecting the bit error of the digital subscriber line and displaying the bit error.

1 is a block diagram showing a general connection of an integrated telecommunication network switch and an integrated telecommunication telephone.

2 is a block diagram showing an embodiment of a bit error test apparatus for a telecommunication line according to the present invention;

3 is a view illustrating noise generated by the noise provider of FIG. 2 in relation to frequency and level;

FIG. 4 is a diagram illustrating a noise limit corresponding to the noise frequency of FIG. 3. FIG.

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

12: network termination device 14: digital subscriber line

16: noise providing unit 18: noise frequency adjusting unit

20: noise level controller 22: noise generator

24: bit error display unit 26: reference signal generator

28: transceiver unit 30: bit error detection unit

32: display unit

Hereinafter, the embodiment of the present invention will be described in detail with reference to the following drawings.

2 is a block diagram showing an embodiment of a bit error test apparatus for a telecommunication line according to the present invention. The network termination apparatus 12, the digital subscriber line 14, the noise providing unit 16, and the bit error display unit ( 24). At this time, the noise providing unit 16 includes a noise frequency adjusting unit 18, a noise level adjusting unit 20, and a noise generating unit 22. In addition, the bit error display unit 24 includes a reference signal generation unit 26, a transceiver unit 28, a bit error detection unit 30, and a display unit 32.

In the figure, since the network termination device 12 basically has a signal reflection function, the signal applied through the digital subscriber line 14 is looped back through the digital subscriber line 14.

The noise frequency adjusting unit 18 in the noise providing unit 16 adjusts the frequency of the noise by a user's operation.

The noise level controller 20 adjusts the level of noise by a user's manipulation.

The noise generator 22 determines a frequency based on the control of the noise frequency controller 18 and generates sinusoidal noise whose level is determined based on the control of the noise level controller 20 to generate the sine wave noise. Is applied to the digital subscriber line 14.

The reference signal generator 26 in the bit error display unit 24 generates a specific reference signal of a degree comparable to the actual integrated information network signal, and provides it to the transceiver 28 and the bit error detector 30.

The transceiver 28 transmits the reference signal provided from the reference signal generator 26 to the network termination device 12 through the digital subscriber line 14 to reflect and mix noise generated from the noise generator 22. The received reference signal is received and provided to the bit error detector 30.

The bit error detection unit 30 compares the signal provided from the transceiver unit 28 with the signal provided from the reference signal generator 26 to detect whether an error has occurred in the signal provided from the transceiver unit 28 to display the display unit ( This error is indicated at 32 so that the user can know whether or not the bit of the digital subscriber line 14 is an error. That is, when the signal provided from the transceiver 28 and the signal provided from the reference signal generator 26 are not the same, it is determined that a bit error has occurred in the digital subscriber line 14. Here, the display unit 32 may be made of a device such as a liquid crystal display (LCD) or a light emitting diode (LED).

At this time, in order to evaluate the influence on the noise by frequency of the above-described network termination device 12, in the digital subscriber line 14 composed of two wires prepared with various network termination devices and introduced into each network termination device By operating the noise frequency adjusting unit 18 so as to derive a characteristic curve for each frequency from a low frequency of 60 Hz to 1 MHz, the frequency generating interval of the sine wave noise generated by the noise generating unit 22 is adjusted. At this time, the noise level adjusting unit 20 is manipulated to adjust the magnitude of the sine wave noise generated by the noise generating unit 22 to find a threshold of the maximum noise level that does not cause a bit error. That is, the noise limit according to the frequency can be found for the noise having the frequency and the level as shown in FIG.

As described above, the present invention measures the noise spectrum of the digital subscriber line 14 so that the allowable limits of the noise shown in FIGS. 3 and 4 corresponding to the respective frequencies can be obtained. Therefore, whenever various types of network terminators are used, referring to FIGS. 3 and 4, it is possible to easily determine whether a digital subscriber line connected to the current network terminator causes a bit error.

Claims (4)

A bit error test apparatus for a telecommunication line having a network termination device connected to a digital subscriber line, comprising: A noise providing unit providing noise to the digital subscriber line; As the reference signal is transmitted to the network termination device through the digital subscriber line, the network signal is reflected by the network termination device and returned through the digital subscriber line. The reference signal is received by mixing the noise provided from the noise provider. A bit error test apparatus for a telecommunication line comprising a bit error display unit for detecting a bit error of a digital subscriber line and indicating whether the bit error exists. The method of claim 1, And the noise providing unit provides noise to the digital subscriber line on the side of the network termination device. The method according to claim 1 or 2, The noise providing unit includes a noise frequency adjusting unit for adjusting the frequency of the noise; A noise level controller for adjusting a level of noise; And a noise generator for determining a frequency based on the control of the noise frequency adjusting unit and generating a noise whose level is determined based on the control of the noise level adjusting unit. The method according to claim 1 or 2, The bit error display unit may include a reference signal generator configured to generate a specific reference signal; Transmitting and receiving unit for receiving a reference signal reflected by the noise generated from the noise providing unit by transmitting the reference signal provided from the reference signal generator to the network termination device through the digital subscriber line; A bit error detection unit detecting whether an error occurs in a signal provided from the transceiver by comparing the signal provided from the transceiver with a signal provided from the reference signal generator; And a display unit for indicating a bit error of the digital subscriber line based on a detection signal from the bit error detection unit so that a user can know the bit error of the digital subscriber line.