JPH0888622A - Delay difference absorption method - Google Patents

Abstract

(57) [Summary] [Purpose] Absorption of delay differences used in, for example, a signal switching system without interruption by matching the phases of signals that have passed through two transmission lines with different lengths and different delay times. With regard to the method, it is possible to make an adjustment to eliminate the delay difference between the signals that have passed through the two transmission lines at high speed without making an error in the determination of the delay time difference, and to lose the frame synchronization when adjusting the delay difference. The purpose is to realize a delay difference absorption method with a small circuit scale that does not exist. On the transmitting side, a specific pattern that is different from the frame synchronization pulse of the transmission signal and is synchronized with the frame synchronization pulse is switched to the input transmission data, and the frame synchronization pulse is inserted into the specific pattern to insert the two transmissions. Then, at the receiving side, at the time of frame synchronization of the respective received signals from the two transmission lines, the specific pattern is extracted and the two specific patterns extracted are compared to determine the two transmission lines. The delay difference is determined and the delay difference is adjusted so as to be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to, for example, a non-interruptible signal switching system by matching the phases of two systems of received signals that have passed through two transmission lines having different line lengths and different delay times. It relates to the delay difference absorption method used.

[0002]

2. Description of the Related Art In the conventional delay difference absorption method, referring to the block diagram of the conventional example of FIG. 3, the transmission side outputs an output of a timing generator 30 for generating a fixed cycle timing for frame synchronization in transmission input data. Based on the above, the frame pattern generated by the frame pattern generation unit 20 is inserted by the frame pattern insertion unit 10, and the signal distribution unit 40 causes two transmission lines A and transmission lines having different delay times and different delay times. Distribute to B and send. Then, the receiving side processes the received signals RA and RB of the two systems respectively received from the two transmission lines A and B having different delay times, and matches the phases of the received signals RA and RB.
When switching between 2 signals SA and SB without interruption,
In each frame synchronization section 50A, 50B and delay adjustment section 60A, 60B,
By comparing the detection times of the two frame synchronization pulses detected from each of the received signals RA and RB, the difference in delay time between the two transmission paths A and B is detected, and the delay amount is adjusted so that the delay time difference disappears. The method of adjusting and absorbing the phase difference was adopted.

[0003]

The above-mentioned conventional delay difference absorption method has the following problems. If the delay time difference between the two transmission lines A and B is longer than the cycle of the frame synchronization pulse of the transmission signal, the delay adjustment units 60A and 60B on the receiving side will adjust the phase of the reception signals RA and RB of the two systems. When the lead / lag phase difference is determined, there is a possibility that the determination may be erroneous. When determining the phase difference, a measuring instrument such as a synchroscope is required, and the delay is adjusted manually. By comparing the detection times of the two frame synchronization pulses detected from each received signal RA, RB, the two transmission lines A,
In order to detect the difference in the delay time of B, the frame synchronization unit 50A,
The delay adjustment units 60A and 60B are arranged before the 50B, but for this reason, if the delay adjustment units 60A and 60B are used to operate the delay amount, the frame synchronization units 50A and 50B in the subsequent stages lose the frame synchronization. Therefore, it is necessary to take a long time to determine the delay difference to be finally absorbed because the delay adjustment units 60A and 60B again compare the delay amounts after the frame synchronization units 50A and 50B bring the synchronization state. did. An object of the present invention is to make an adjustment to eliminate the delay difference between each other at high speed without making an error in the determination of the delay time difference between the reception signals of the two systems that have passed through the two transmission paths A and B, and The purpose is to realize a delay difference absorption method with a small circuit scale so that frame synchronization is not lost during adjustment to eliminate the delay difference.

[0004]

To achieve this object, a delay difference absorption system of the present invention refers to the principle diagram showing the basic configuration of FIG. 1 and claims two different delay time differences. Received signals (RA, RB) of two systems coming through the transmission path (A, B)
In the delay difference absorption method that adjusts so as to eliminate the delay difference, the transmitting side generates a specific pattern that is different from the frame synchronization pulse of the transmission data and is synchronized with the frame synchronization pulse After inserting the frame sync pulse in the pattern, the signals are distributed to the two transmission paths (A, B) and transmitted. On the receiving side, the two reception signals (RA, RB) are received.
At the time of each frame synchronization, the specific pattern therein is taken out, the delay difference between the two transmission paths is judged by comparing the two extracted specific patterns, and the delay difference is adjusted so as to be eliminated. Next, as a claim 2 for the purpose of simplifying the entire circuit by utilizing an existing partial circuit, when generating a specific pattern on the transmitting side, generation timing information of a frame synchronization pulse of an existing transmission signal. On the basis of the above, the specific pattern is generated in a cycle in which this information is divided. Next, the specific pattern generated on the transmitting side as claimed in claim 3, wherein the receiving side eliminates an error in the determination of the phase difference between the lead and lag of the phases of the received signals (RA, RB) of the two systems. If the delay difference that must be absorbed by judging the delay difference between the two transmission lines by extracting a specific pattern from each received signal (RA, RB) on the receiving side is N bits, The number of bits is increased by 1 bit (N + 1). Next, on the receiving side, it is an object to speed up the convergence of the judgment of the phase difference between the lead and lag of the phases of the received signals (RA, RB) of the two systems and speed up the phase matching.
As a method for determining the delay difference between the two transmission lines on the receiving side, when comparing bits of a specific pattern extracted from the received signal (RA, RB), one of the two transmission lines A, B The bit width of one specific pattern is set to the period (N +
The delay amount is controlled by using the comparison result after the comparison is performed after the extension is made larger than ½ of 1). In addition, as a purpose of preventing frame synchronization from being lost at the time of adjustment for eliminating the delay difference on the receiving side, a delay for performing the adjustment for eliminating the delay difference of the two transmission lines on the receiving side as claim 5. The adjusting unit (60A, 60B) is configured to be provided after the frame synchronizing unit (50A, 50B) that detects a frame synchronizing pulse and establishes frame synchronization.

[0005]

According to the structure of claim 1 of the present invention, the transmitting side generates a specific pattern in synchronization with the frame synchronization pulse of the conventional transmission signal in addition to the frame synchronization pulse of the conventional transmission signal, switches it with the input transmission data, and After inserting a frame sync pulse in a specific pattern, the frame sync pulse is distributed to the two transmission paths (A, B) and transmitted. Also, on the receiving side, the method of determining the delay difference between the two transmission paths (A, B) is not the conventional method of comparing the detection time of the frame synchronization pulse, but each received signal (RA, RB).
The delay difference between the two transmission lines is determined by comparing two specific patterns extracted from each of them at the time of frame synchronization, and the delay difference between the two transmission lines is adjusted so that the delay difference disappears. Even if it is longer than the cycle of the sync pulse, it is possible to prevent an erroneous determination of the lead / lag of the phase difference between the reception signals (RA, RB) of the two systems.

In the configuration of claim 2, when the specific pattern is generated on the transmitting side, the specific pattern is generated based on the generation timing information of the frame synchronization pulse of the existing transmission signal, so that the entire circuit is simplified. It

In the third aspect of the invention, the period of the specific pattern generated on the transmitting side must be absorbed by the receiving side by extracting the specific pattern from each received signal (RA, RB) and determining the delay difference between the two transmission lines. If the delay difference that must be N bits,
Since the number of bits is at least one bit larger (N + 1) than the N bits, it is possible to prevent an erroneous determination of the lead / lag of the phase difference of the received signals (RA, RB).

According to the fourth aspect of the invention, as a method of determining the delay difference between the two transmission lines on the receiving side, when comparing bits of a specific pattern extracted from the received signals (RA, RB), the two transmission lines are compared. Since the bit width of one of the specific patterns of A and B is extended by more than half of the period (N + 1) and compared, the received signal (RA, R
The convergence of the phase difference judgment of the phase lead / lag of B) becomes faster,
Since the delay amount is controlled by using the comparison result, the phases of the received signals (RA, RB) can be adjusted at high speed.

According to a fifth aspect of the present invention, the delay adjusting section (60A, 60B) for adjusting the delay difference between the two transmission lines on the receiving side is provided with a frame synchronizing section (50A, 60A, 60A, 60B) for detecting a frame synchronizing pulse. Since it is provided in the latter stage of (50B), the frame synchronization will not be lost during adjustment to eliminate the delay difference, and the delay difference can be absorbed faster.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The principle diagram of the present invention shown in FIG. In FIG. 1, a frame pattern inserting section 10 on the transmitting side, a timing generating section 1 of the frame pattern generating sections 20, 30 and a signal distributing section 40 are conventional functional circuits, and are a signal switching section 1, a specific pattern generating section 2, The timing generator 2 of 3 is a new circuit according to the present invention. In addition, the frame synchronization unit 50A, 50B on the receiving side, the delay adjustment unit 60A,
60B and the signal selecting unit 70 are conventional functional circuits, the specific pattern bit width operating unit 4 and the specific pattern comparing unit 5 are new circuits according to the present invention, and the delay adjusting units 60A and 60B.
Is also arranged after the frame synchronization units 50A and 50B according to the present invention.

FIG. 2 is a time chart of the operation of the embodiment shown in FIG. 1, in which FIG. Referring to FIG. 1 and FIG. 2, on the transmitting side, a timing pulse having a constant cycle output from the timing generating unit 1 for generating a frame pattern for frame synchronization is passed to the timing generating unit 2 for generating a specific pattern. The timing generator 2 divides the timing pulse output from the timing generator 1 to generate a timing pulse necessary for the specific pattern generator 2. In this way, the entire circuit can be simplified by utilizing the timing pulse from the frame pattern timing generation unit 1 of the conventional circuit. (Claim 2
Equivalent to). The specific pattern generation unit 2 creates a specific pattern using the timing pulse and transfers it to the signal switching unit 1. The signal switching unit 1 switches (selects) input transmission data and a specific pattern, and selects a specific pattern when adjusting the delay difference between the two transmission lines A and B. The signal of the specific pattern selected by the signal switching unit 1 is sent to the frame pattern inserting unit 10. The frame pattern insertion unit 10 inserts the frame pattern from the frame pattern generation unit 20 into the signal and outputs an insertion output. The inserted output is the signal distribution unit 40
It is distributed to A and transmission path B and sent to the receiving side. On the receiving side, the signals that have passed through the transmission lines A and B are received, and the received signals RA and RB have different delay times and are input to the frame synchronization units 50A and 50B. In the frame synchronization units 50A and 50B, the input reception signal, is synchronized with the frame, and at the time of the frame synchronization, only the specific pattern in the reception signal is extracted and the specific patterns (9) and (14) are output. To do. The specific pattern (9) of the A side output enters the specific pattern bit width operation unit 4, is divided, and outputs (11) to (1
As in 3), the bit width is expanded and input to the specific pattern comparison unit 5. In the specific pattern comparison unit 5, time comparison between the A side outputs (10) to (13) and the B side output (14) is performed at one time so that the delay difference between the transmission lines A and B can be detected at high speed. To do. (Corresponding to claim 4). The determination outputs (15) and (16) are obtained as the comparison result, but (15) and (16) are the same. In this embodiment, it is assumed that the received signal on the A side is selected and operates so as to match the received signal on the B side. Then, the judgment output (15) on the A side is not output and B
It operates so that only the side judgment output (16) is output. The delay difference information of the determination output (16) is input to the delay adjusting unit 60B, and the outputs (17) and (18) are obtained from the delay adjusting units 60A and 60B. In this case, since the delay difference information of the judgment output (16) is input all at once from the specific pattern comparison unit 5 to the delay adjustment unit 60B, the delay adjustment unit 60B instantaneously inserts or extracts the delay. The delay can be adjusted at high speed. Then, after the delays match, the input signal (17)
(18) can be switched.

Further, as can be seen by comparing and in FIG. 2, if the period of the frame pulse is shorter than the range of the delay difference absorption, the phase lead / lag cannot be determined. By making the cycle longer than the range of delay difference absorption, it becomes possible to judge. (Corresponding to claim 3). In addition, since the delay adjustment units 60A and 60B are arranged after the frame synchronization units 50A and 50B, the delay adjustment units 60A and 60B are
Even if the delay adjustment is performed at B, the frame synchronization of the received signals at the frame synchronization units 50A and 50B will not be lost. (Corresponding to claim 5).

[0013]

As described above, according to the present invention, it is possible to perform the adjustment for eliminating the delay difference at high speed without making an error in the determination of the delay difference between the two transmission lines. Also, the frame synchronization will not be lost when the delay difference is adjusted.
Furthermore, the effect of adjusting the delay difference can be obtained without using a measuring device or the like.

[Brief description of drawings]

FIG. 1 is a principle diagram showing a basic configuration of a delay difference absorption method of the present invention.

FIG. 2 is a time chart for explaining the operation of the embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional delay difference absorption method.

[Explanation of symbols]

1 is a signal switching unit on the transmitting side, 2 is a specific pattern generation unit, 3
Is a timing generation unit 2, 4 is a receiving side specific pattern bit width operating unit, and 5 is a specific pattern comparing unit.

Claims (5)

[Claims] 1. In a delay difference absorption system for adjusting so as to eliminate a delay difference between two systems of received signals which have passed through two transmission lines having a difference in delay time, a frame synchronization pulse of a transmission signal is on a transmission side. Another specific pattern synchronized with the frame synchronization pulse is switched to the input transmission data, the frame synchronization pulse is inserted into the specific pattern and distributed to the two transmission lines for transmission, and the reception side transmits the two transmissions. Taking out the specific pattern from each received signal from the path, judging the delay difference between the two transmission paths by comparing the extracted two specific patterns, and adjusting so as to eliminate the delay difference. Delay difference absorption method characterized by. 2. When the specific pattern is generated at the transmitting side, the specific pattern is generated at a cycle obtained by dividing the information based on the generation timing information of the frame synchronization pulse of the transmission signal. The differential delay absorption method according to claim 1. 3. The delay difference, which must be absorbed by the receiving side by extracting the specific pattern from each of the two received signals and determining the delay difference between the two transmission paths in the cycle of the specific pattern generated on the transmitting side, is N. 2. The delay difference absorption method according to claim 1, wherein when the number of bits is 1, the number of bits is at least 1 bit larger than the N bits (N + 1). 4. A method for determining a delay difference between two transmission lines on the receiving side, wherein when comparing two bits of two specific patterns extracted from received signals of two systems, one of the two transmission lines is used. The bit width of the specific pattern is set to the period (N +
The delay difference absorption method according to claim 1, wherein the convergence of the determination of the delay difference is speeded up by making a comparison after extending the distance by more than one half of 1). 5. A circuit (60A, 60B) for adjusting the delay difference between the two transmission lines on the receiving side is provided in the circuit (50A, 50B) for detecting a frame synchronization pulse and for frame synchronization. The delay difference absorption method according to claim 1, wherein the delay difference absorption method is provided in a subsequent stage to prevent the frame synchronization from being lost when the delay difference is adjusted.