JP2001119326A - Transmission line monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission line monitoring device detecting a bipolar violation signal even if the code rule of the continuous pulses of the same type is used. SOLUTION: A data extraction part 11 extracting type data of a continuous code rule showing the continuity of the codes of the same type, which are used for transmission data, from transmission data of the received bipolar code rule, received positive pole side data only by the polarity of a positive side and received negative pole side data only by the polarity of a negative side, code rule detectors 12 to 14 which are switched by data by continuous code rule type data, detect the continuous code rule from received positive pole side data and received negative pole side data, decode the continuous code rule into continuous data of the same type code and output it and a bipolar violation signal detector 15 detecting the violation (error) of a bipolar signal from decoding positive side data and decoding negative pole side data, which are decoded by the code rule detectors 12 to 14, are installed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission line monitoring apparatus capable of detecting a bipolar violation signal from data transmitted using a code rule indicating the same type of continuation.

[0002]

2. Description of the Related Art Conventionally, a monitoring apparatus for detecting an error in transmission data used in a digital communication apparatus has been proposed to detect transmission of noise in transmission data and to improve transmission quality.
There is known a bipolar signal in which “1” pulses in transmission data of a combination of “1” pulses and “0” pulses are alternately arranged on a positive electrode side and a negative electrode side and transmitted to a transmission path. As shown in FIG. 5, the coding rule of the bipolar signal is to output a zero level when the pulse is "0" and output a positive and negative pulse alternately when the pulse is "1". Therefore, when pulses of the same polarity are continuously received, it is data that violates the above-mentioned coding rule (violation), so that it is detected on the receiving side that an error signal has been mixed in the transmission path or the like. it can. FIG. 5 is a timing chart showing an example of a case where a bipolar violation signal is generated when transmitting transmission data as a bipolar signal through a transmission path. The three timing charts from the top in FIG. 5 are those on the transmission side. In the order from the top, (a) is the transmission side clock, (b) is transmission data which is a digital pulse to be transmitted, and (c) is transmission. A transmission transmission path pulse signal transmitted (transmitted) to the transmission path. The transmission device on the transmission side forms a pulse “1” in the transmission data alternately on the positive side and the negative side with respect to the reference level based on the timing of the clock pulse, and (c)
Is transmitted to the transmission path as shown in FIG. The fourth timing chart (d) from the top in FIG. 5 shows an unintended noise pulse or the like (violation signal) mixed in the transmission path from the transmission side to the reception side. The fifth and subsequent timing charts from the top in FIG. 5 are those on the receiving side, and in order from the top, (e) is a bipolar signal received from the transmission path,
(F) is the receiving clock, (g) is the received data before the bipolar violation processing, and (h) is the received data (= transmission data) after the bipolar violation processing.

As shown in FIG. 5E, the received bipolar signal contains a noise pulse shown in FIG. 5D, so that pulses of the same polarity (positive electrode side) are continuous. Upon detecting the signal shown in FIG. 5E, the receiving apparatus determines that there is an error in the data received from the transmission path, and requests the transmitting side to retransmit the transmission data. In order to detect a bipolar violation signal from the received bipolar signal as described above, a method based on a redundancy code check (cyclic redundancy check: CRC) is generally known. When the transmission data is input, the CRC detector counts the total number of 1s and 0s in the transmission data for a predetermined time (for example, one second), and determines the number of error detection characters (CRC characters) transmitted. If the total number does not match, it is determined that the transmission data has not been correctly received.
Outputs an error signal. Then, the receiving side device requests the transmitting side of the transmission data to retransmit the transmission data based on the CRC error signal. On the other hand, using the violation in which the same polarity side signal in the coding rule of the bipolar signal is continuous, for example, when the “0” pulse continues in the transmission data, the next received “1” pulse is synchronized. In order to improve transmission quality by solving problems such as hardening, a coding rule is used that replaces continuous zero data in a case where a predetermined number of same-type code "0" pulses are continuous with data of a predetermined format that can be distinguished from other data. It is known. For example, the HDB3 code that is replaced when four “0” s are consecutive is a code adopted as a transmission line code in a CEPT digital transmission system that is widely used mainly in Europe. The outline of this code is as follows. (1) Four consecutive “0” patterns are detected, and the fourth bit “0” is referred to as a pulse called “violation signal (hereinafter abbreviated as V pulse)” (“1” or “−”).
1 "). This conversion pattern is referred to here as "00
0V ". (2) After converting a certain V pulse to “1”, the next V pulse
The pulse is converted to "-1". (3) The number of bipolar signals (hereinafter abbreviated as B pulses; B pulses are also "1" or "-1") existing between two V pulses is always an odd number. Therefore, when the B pulse is an even number, “0” of the first bit of four consecutive “0” s
Is converted to a B pulse. At this time, the fourth bit is converted into a V pulse. This conversion pattern is referred to as “B00V” here.
Abbreviated.

FIG. 6 is a diagram for explaining the HDB3 coding rule. The four timing charts from the top are for the transmitting side.
(B) is transmission data that is an original digital pulse to be transmitted, and (c) is a transmission transmission path pulse signal transmitted (transmitted) to the transmission path. Also in this case, on the transmission side, the transmission data is transmitted to the transmission path as a pulse that alternately appears on the positive and negative sides of the reference level according to the clock timing. Note that (d) is opposite to the transmission transmission path pulse signal shown in (c), with the polarity reversed and reversed (reverse polarity).
9 shows a transmission transmission path pulse signal. The fifth timing chart after FIG. 6E from the top in FIG. 6 is for the receiving side, and from the top, (e) is the receiving side clock,
(F) shows received data before HDB3 coding rule processing, and (g) shows received data (= transmission data) after HDB3 coding rule processing. The above-described examples in FIGS. 6A to 6D show the timing of signals on the transmission line when no noise is mixed. On the receiving side, the HDB3 coding rule in the received bipolar signal is decoded into a sequence of four “0” pulses and sent to the next circuit or processing step as received data.

FIG. 7 is a timing chart showing a B8ZS coding rule to be replaced when eight "0" s are consecutive. In FIG. 7 as well, the four timing charts from the top are those on the transmission side, and from the top, (a) is the transmission side clock, (b) is transmission data that is the original digital pulse to be transmitted, and (c) Is a transmission transmission path pulse signal transmitted (transmitted) to the transmission path. Also in this case, on the transmitting side,
The transmission data is transmitted to the transmission line as a pulse that alternately appears on the positive and negative sides of the reference level in accordance with the clock timing. (D) shows a transmission transmission line pulse signal in which the polarity of the transmission transmission line pulse signal shown in (c) is reversed and the polarity is reversed (reverse polarity). The fifth timing chart after FIG. 7 (e) from the top in FIG. 7 is for the reception side. From the top, (e) is the reception side clock, (f) is the reception data before B8ZS coding rule processing, (G) shows the reception data (= transmission data) after the B8ZS coding rule processing. The examples in FIGS. 7A to 7D also show the timing of signals on the transmission line when no noise is mixed. On the receiving side, the B8ZS coding rule in the received bipolar signal is decoded into a sequence of eight “0” pulses, and sent to the next circuit or processing step as received data.

[0006]

However, even when the above-described code rule of the same kind of continuous pulse is used, a case where the "1" pulse on the same pole side is continuous due to the mixing of noise pulses in the transmission line occurs. . However, since the CRC detector merely checks the total number of "1" and "0", the case where "1" pulses on the same polarity side are continuous due to the coding rule, and the same polarity due to mixing of an error signal. It cannot be distinguished from the case where the “1” pulse on the side continues. Therefore, a conventional transmission line monitoring device using the same continuous pulse coding rule, that is, a system using a coding rule such as HDB3 or B8ZS, cannot detect a bipolar violation signal generated by noise. The present invention has been made in order to solve the conventional problems as described above, and is a transmission line monitoring apparatus capable of detecting a bipolar violation signal even when using the same continuous pulse coding rule. The purpose is to provide.

[0007]

In order to achieve the above-mentioned object, a transmission line monitoring apparatus according to the present invention uses a continuous code indicating a continuation of the same code used for the transmission data from the received transmission data of the bipolar code rule. A data extraction unit for extracting the positive polarity data only for the positive polarity and the reception negative data only for the negative polarity; and the reception positive polarity switched by the continuous coding rule type data. A code rule detector for detecting the continuous code rule from data and reception negative electrode side data, decoding the continuous code rule into continuous data of the same type of code, and outputting the decoded code rule; and a decoding positive electrode decoded by the code rule detector. A bipolar violation signal detector for detecting a violation (error) of the bipolar signal from the side data and the decoded negative electrode side data.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on illustrated embodiments. FIG. 1 is a block diagram showing a configuration of an embodiment of a transmission line monitoring device according to the present invention. As shown in FIG. 1, the transmission line monitoring apparatus according to the present embodiment is configured to perform code generation when continuous code rule data is included in a reception bipolar transmission pulse having positive and negative bipolar pulses transmitted through the transmission line. A data extraction unit 11 that outputs a rule switching pulse and extracts only data on the positive side (positive side data) and data only on the negative side (negative side data); The positive side shift register 12 which outputs the decoded positive side data returned from the HDB3 coding rule detector 14 and outputs the decoded positive side data to a later-stage BPV error detector 15 which will be described later, and inputs the negative side data. HDB3 coding rule detector 14
, And outputs the decoded negative data returned from the HDB3 coding rule detector 14 to a later-stage BPV error detector 15 described later.
And the positive and negative transmission line data and the code rule switching pulse from the positive shift register 12 and the negative shift register 13 are input, and the input transmission line data is decoded by the selected type of continuous coding rule. HDB3 coding rule detector 14 which converts the data into the original polarity side shift registers 12 and 13
And the transmission line data decoded from the positive shift register 12 and the negative shift register 13 to detect a bipolar violation signal, that is, a pulse continuously appearing on the positive side or the negative side in the bipolar coding rule. BP that sends an error signal for requesting retransmission of transmission data to the transmission side of transmission path data upon detection.
And a V error detector 15. The coding rule switching pulse output from the data extracting unit 11 and the transmission line data on the positive and negative sides are input to the HDB3 coding rule detector 14, and after three “0” pulses continue, the signal changes to the positive or negative side. "1"
If there is a pulse input, the last "1" pulse is decoded as a "0" pulse and returned to the positive and negative polarity shift registers 12 and 13, respectively. The BPV error detector 15 detects a bipolar violation (BPV) error based on the road data. With this configuration, the continuous coding rule is BPV.
Before being input to the error detector 15,
The error detector 15 receives only the error signal mixed in the transmission path.

FIG. 2 is a timing chart showing one embodiment of the pulse input / output to / from the data extraction unit in FIG. All the timing charts in FIG. 2 are those on the receiving side. In order from the top, (a) shows the received bipolar transmission path pulse signal input to the data extraction unit, and (b)
Is the clock on the receiving side input to the data extracting unit, etc., (c)
Indicates positive-side data only on the positive side in transmission data input to the data extraction unit, and (d) indicates negative-side data only on the negative side in transmission data input to the data extraction unit. The transmission path pulse signal in FIG. 2A indicates transmission data in which “1” is continuous. In this case, FIG.
As shown in (d), the positive data and the negative data are output alternately. Next, FIG. 3 is a timing chart showing a process of decoding transmission data including the HDB3 coding rule. All of the timing charts in FIG. 3 are those on the receiving side. In order from the top, (a) shows a received bipolar transmission path pulse signal including the HDB3 coding rule,
(B) is a receiving clock input to each unit in FIG.
(C) shows data from the data extraction unit 11 to the positive shift register 1
Positive data only on the positive side in the transmission data to the second, (d)
Is negative-side data only on the negative side in the data transmitted from the data extracting unit 11 to the negative-side shift register 13; (e) is decoded positive-side data from the positive-side shift register 12 to the BPV error detector 15; f) shows decoded negative data from the negative shift register 13 to the BPV error detector 15. The transmission path pulse signal in FIG. 3A includes the HDB3 coding rule. Therefore, the transmission path pulse signal includes “0001” including the positive “1” after the positive “1” in the transmission path pulse signal. The pulse is decoded to “0000” by the HDB3 coding rule detector 14, returned to the shift registers 12 and 13 on the respective polarity sides, and output to the BPV error detector 1.
5 is output. At this time, no error is detected because the signal is processed according to the HDB3 coding rule. FIG.
3 is a timing chart showing BPV error detection after decoding processing of the HDB3 coding rule in the configuration of FIG.
All the timing charts in FIG. 4 are for the receiving side, and (a) shows the HDB3 coding rule and the BPV in order from the top.
1. A received bipolar transmission path pulse signal including both errors, (b) a receiving clock input to each unit in FIG. 1, and (c) decoded from the positive shift register 12 to the BPV error detector 15. Positive data, (d) shows the decoded negative data from the negative shift register 13 to the BPV error detector 15, and (e) shows the BPV error detected by the BPV error detector 15 from both decoded data. Shows the data.

The transmission line pulse signal shown in FIG.
In this case, an error and an HDB3 coding rule are included.
3 and the HDB3 coding rule detector 14 decodes the HDB3 coding rule. "1" on the positive side in the transmission path pulse signal
The pulse of “0001” including “1” on the positive side after “H” is H
The data is decoded to “0000” by the DB3 coding rule detector 14, returned to the shift register on each polarity side, and output to the BPV error detector 15. BPV error detector 15
Detects a case where a positive pulse continues or a case where a negative pulse continues from both decoded data, and outputs a bipolar violation (BPV) error pulse at the timing of the subsequent pulse. With this BPV error signal, a retransmission request or the like is sent to the transmission data transmission side, so that error-free transmission data can be obtained.
In the above, only the pattern of “0001” has been described. However, in the HDB3 coding rule, “1001” (“BDB
V ") pattern also appears. In this regard, similarly, a BPV error can be detected and a pulse of the BPV error can be output. Also, when the B8ZS coding rule is used instead of the HDB3 coding rule for the transmission path signal, only the HDB3 coding rule of 4 codes in FIGS. 3 and 4 is replaced with the B8ZS coding rule of 8 codes. In the same manner as above, a BPV error can be detected and a pulse of the BPV error can be output. By configuring and operating the transmission path monitoring device as described above, even when data is transmitted using a continuous “0” signal rule such as the HDB3 code rule or the B8ZS code rule, bipolar violation The transmission path monitoring device can detect a signal.

[0011]

As described above, according to the present invention, since the continuous coding rule is decoded into continuous pulses of the same kind of code and then the bipolar violation signal is detected,
Even when data is transmitted using a continuous “0” pulse code rule such as the DB3 code rule or the B8ZS code rule,
A transmission path monitoring device capable of detecting a bipolar violation signal can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a transmission line monitoring device of the present invention.

2 (a) to 2 (d) are timing charts showing one embodiment of a pulse input / output to / from a data extraction unit in FIG.

3 (a) to 3 (f) are timing charts showing decoding processing of the HDB3 coding rule which is a continuous coding rule representing four consecutive zeros in the configuration of FIG.

4 (a) to 4 (e) show HDB3 in the configuration of FIG.
FIG. 10 is a timing chart illustrating BPV error detection after decoding of a coding rule.

FIGS. 5A to 5H are timing charts showing an example of a case where a bipolar violation signal is generated when transmitting transmission data on a transmission side as a bipolar signal through a transmission path.

FIGS. 6A to 6G are timing charts showing HDB3 coding rules to be replaced when four “0” s are continuous.

FIGS. 7A to 7G are timing charts showing a B8ZS coding rule to be replaced when eight “0” s are continuous.

[Explanation of symbols]

11 ... data extraction unit, 12 ... (positive electrode side) shift register, 13 ... (negative electrode side) shift register, 14
... HDB3 coding rule detector, 15 ... Bipolar violation (BPV) detector

Claims (1)

[Claims] 1. Type data indicating a continuous code rule indicating a continuation of the same code used for transmitting a received transmission path signal from a reception transmission path signal conforming to a bipolar coding rule,
A data extraction unit for extracting the reception positive side data only of the reception transmission line signal of the positive polarity and the reception negative side data only of the reception transmission line signal of the negative polarity, and the data extraction unit extracts the data. The continuous code rule detected by the type data is switched, the continuous code rule is detected from the reception positive electrode side data and the reception negative electrode side data, and the continuous code rule is decoded into the same code continuous data and output. A transmission line monitoring device comprising: a detector; and a bipolar violation signal detector that detects a violation of a bipolar signal from the decoded positive data and the decoded negative data decoded by the code rule detector. .