JPS63202150A - Information signal transmission system - Google Patents

Abstract

PURPOSE:To prevent the propagation of an error due to mis-detection of a synchronizing signal by sending a position information signal representing the location of a 1st synchronizing signal, the 1st synchronizing signal corresponding to a prescribed quantity of information signal and plural 2nd synchronizing signals having the synchronizing information signals altogether. CONSTITUTION:An auxiliary synchronizing signal consists of 8-bit address information being a position information signal representing the position of the 1st synchronizing signal and a 16-bit synchronizing signal being a synchronizing signal in the auxiliary synchronizing signal. The synchronizing signal included in the auxiliary synchronizing signal from the transmission signal is detected. When the synchronizing signal is not detected, the 1st synchronizing signal is detected. When the signal is not detected, the auxiliary synchronizing signal is detected, since the position of the 1st synchronizing signal to be detected is predicted, then the signal equal to the 1st synchronizing signal is sent to the predicted location when the detection error of the 1st synchronizing signal is caused.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an information signal transmission system for transmitting information signals.

[Conventional technology]

Conventionally, for example, in order to correctly restore the original data sequence when receiving or reproducing a digital signal sequence, a synchronization signal indicating the start of data or the delimitation of data is transmitted together with an information signal during horizontal multiplication, and the synchronization signal is accurately transmitted. need to be detected.

However, the synchronization signal is disturbed by various disturbances in the transmission path, resulting in failure to detect the synchronization signal, or generation of so-called pseudo synchronization signals in which a signal other than the original synchronization signal is mistakenly regarded as a synchronization signal. etc., resulting in erroneous detection of the synchronization signal.

Errors in synchronization signal detection as described above cause large error propagation when restoring a data sequence, so protection measures are required.

Conventionally, as a protection measure for synchronization signals, a method using a detection window has been announced. This method uses the synchronization signal of the detection stream as a reference, sets a detection window near the position of the original synchronization signal that may appear after that, and detects the synchronization signal only within the range of the detection window. The idea is to prevent the generation of signals.

[Problem that the invention seeks to solve]

However, in the conventional case as described above, if the setting of the detection window ≠ it is not possible to detect the synchronization signal used for honing, not only the above-mentioned effect cannot be expected, but also the error occurs. This had the disadvantage of causing amplification of propagation.

The present invention has been made in view of the above-mentioned problems, and provides an information signal transmission system that can detect synchronization signals with high reliability and prevent propagation of errors due to erroneous detection of synchronization signals. The purpose is to provide.

[Means to solve the problem]

The information signal transmission system of the present invention includes a first synchronization signal corresponding to a predetermined amount of information signals, and a plurality of second synchronization signals each having a position information signal and a synchronization information signal each representing at least the position of the first synchronization signal. The signal is transmitted together with the predetermined amount of information signal, or the predetermined amount of information signal transmitted as described above is restored based on at least the second synchronization signal.

[Effect]

According to the above configuration, if any one of the plurality of second synchronization signals can be detected when restoring the information signal, the detected second synchronization signal The first synchronization signal can be reliably detected based on the position information signal.

〔Example〕

Hereinafter, the present invention will be explained using one embodiment of the present invention.

FIG. 1 is a diagram showing, as an embodiment of the present invention, a schematic configuration when the present invention is applied to an information signal transmission system that digitizes and transmits information signals.

In FIG. 1, an input analog information signal is supplied to an encoding circuit 51, and the encoding circuit 51 obtains information data by digitizing the supplied analog information signal every predetermined amount. The information data is supplied to a synchronization signal addition circuit 52.

On the other hand, the synchronization signal generation circuit 53 generates first and second synchronization signals as described later based on the input tarock signal, and the generated first and second synchronization signals are sent to the synchronization signal addition circuit 52. Supplied.

Then, in the synchronization signal addition circuit 52, first and second synchronization signals corresponding to the supplied information data are added to the information data, and then in the modulation circuit 54, the synchronization signals are added to the information data so as to match the characteristics of the transmission path 55. The signal is subjected to modulation such as NRZI modulation and transmitted to the transmission path 55.

Here, the transmission format of the information signal in this embodiment will be explained.

FIG. 2 is a diagram showing an example of an information signal transmission format in the information signal transmission system shown in FIG. 1.

In FIG. 2, the first sync block 1 is connected to the first sync signal 2 (16
This block consists of an information signal sequence of 3 bits) and 3 bits. Normally, transmission starts from this first sync block, but in this embodiment, a group of four auxiliary synchronization signals, which are second synchronization signals, are inserted before this first sync block. This auxiliary synchronization signal group is composed of a plurality of auxiliary synchronization signals, each of which is 8-bit address information that is a position information signal indicating the position of the second first synchronization signal, and a synchronization signal within the auxiliary synchronization signal. It is composed of a 16-bit synchronization signal, and corresponds to 21 to 25 and 31 to 35, respectively, in the figure.

FIG. 3 is a diagram showing an example of the structure of the address information. The address information 20 is a 3-bit address 4414.
3-bit error correction code S4:l, 2-bit CD
S (Code word Digital Su
m)=] control bit consists of a total of 43 moxibustions. 4
Address 1 is information indicating the position of the first synchronization signal 2 counted from the auxiliary synchronization signal, and by detecting this information at the time of reception, which will be described later, the position of the first synchronization signal can be predicted.

The error correction code No. 42 is for preventing the position of the first synchronization signal from being erroneously predicted when the address information is erroneously detected.

The 43rd CDS control bit is a bit for minimizing the absolute value of the known CDS of this address information, and by inserting an auxiliary synchronization signal group, the known DSV (Digital Sum Value) of the transmission signal string becomes thick ( It is designed to prevent this from happening.

The first synchronizing signal 2 and the auxiliary synchronizing signal group 4 are generated in the synchronizing signal generating circuit 53 of FIG. By doing so, a transmission signal with the transmission format shown in FIG. 2 is obtained.

The restoring operation upon receiving the transmission signal sent out to the transmission path 55 as described above will be described below.

In FIG. 1, a transmission signal transmitted through a transmission line 55 is supplied to a demodulation circuit 56, demodulated to the original No. 1 form, and supplied to a decoding circuit 57 and a synchronization signal detection circuit 58.

The synchronization signal circuit 58 detects a synchronization signal from the supplied transmission signal, and the timing signal generation circuit 59 forms a timing signal for the decoding operation of the decoding circuit 57 according to the detection timing of the synchronization signal. The information signal is extracted based on the timing signal generated at 59, decoded into an analog signal, and output.

The synchronization signal detection operation in the synchronization signal detection circuit 58 of FIG. 1 will be described in detail below.

FIG. 4 is an operation flowchart showing a synchronization signal detection operation for a transmission signal transmitted in the transmission format shown in FIGS. 2 and 3. FIG.

In FIG. 4, the synchronization signal detection circuit 58 of FIG.
When the transmission signals shown in the figures and FIG. 3 are supplied, a synchronization signal detection operation is started in step 101.

First, in step 102, a synchronization signal included in the auxiliary synchronization signal is detected from the transmission signal. If the synchronization signal cannot be detected, steps 106 to 106, which will be described later,
After performing the operation of step 108, the synchronization signal detection operation is performed again.

Next, if a synchronization signal is detected, in step 103, address information in the auxiliary synchronization signal to which the detected synchronization signal belongs is extracted. This address information, for example,
It represents information on how many auxiliary synchronization signals are included before the synchronization signal, and it is determined in step 104 whether or not there is an error in the extracted address information, and if there is an error, the synchronization signal is detected. Assuming that it was not possible, the process proceeds to step 106. If there is no error in the extracted address information, the process proceeds to step 105 and a counter is set based on the extracted address information. Here, if the counter is set even once, it becomes possible to predict the position of the first synchronization signal.

By the way, if the synchronization signal cannot be detected, or if the synchronization signal can be detected but there is an error in the extracted address information, the process proceeds to step 106. Here, before this ±tt
It is determined whether even one synchronization signal is accurately detected. That is, if the counter in step 105 has already been set, it means that a synchronization signal has been detected previously, and if the counter has not been set, it means that no synchronization signal has been detected so far. In the latter case, the process directly advances to step 108.

Furthermore, since the number of bits between synchronization signals in the transmission signal of the transmission format shown in FIG. 2 is constant, once the counter in step 105 is set, the position of the first synchronization signal can be predicted. Even if the first synchronization signal cannot be detected at that position, the counter value is decreased and the position information of the first synchronization signal is updated.

Next, in step 108, it is determined whether the auxiliary synchronization signal group has ended. In other words, if the counter value in step 105 is O, the auxiliary synchronization signal group has ended;
Subsequently, it is determined that the first synchronization signal appears, and the first synchronization signal is detected.

Further, if the counter value is not 0, the process returns to step 102 and the detection of the auxiliary synchronization signal is repeated until the counter value becomes 0.

If the first synchronization signal can be detected, the process directly proceeds to step 111; if it cannot be detected, step 1
Proceed to step 10 to supplement the synchronization signal.

In step 110, by detecting the auxiliary synchronization signal,
Since the position where the first synchronization signal should be detected is predictable,
If a detection error in the first synchronization signal occurs, a signal equivalent to the first synchronization signal is sent to the predicted position. Then, in step 111, the synchronization signal detection operation ends.

Based on the operation flowchart described above, it is possible to accurately predict the position of the first synchronization signal by detecting the synchronization signal included in the auxiliary synchronization signal group, which prevents erroneous detection and prevents detection when detection is impossible. In this embodiment, each synchronization signal in the auxiliary synchronization signal group is provided with error correction capability, and a CDS control bit is also provided. By having the address information included, it is possible to increase the detection probability of the first synchronization signal, and by adding the auxiliary synchronization signal group, it is possible to prevent an increase in the low frequency component of the transmission signal.

Furthermore, in combination with the prior art, this embodiment allows highly reliable detection of synchronization signals that are not detected using a detection window.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to provide an information signal transmission system that can perform highly reliable synchronization signal detection and prevent error propagation due to erroneous detection of synchronization signals. .

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of an information signal transmission system to which the present invention is applied, as an embodiment of the present invention. FIG. 2 is a diagram showing an example of an information signal transmission format in the information signal transmission system shown in FIG. 1. FIG. 3 is a diagram showing an example of the structure of address information in FIG. 2. FIG. 4 is an operation flowchart showing a synchronization signal detection operation for a transmission signal transmitted in the transmission format shown in FIGS. 2 and 3. FIG. 2...First synchronization signal, 21-25...
Address information, 31-35...Synchronization signal, 53
. . . synchronous signal generation circuit, 58 . . . synchronous signal detection circuit.

Claims (1)

[Claims] A first synchronization signal corresponding to a predetermined amount of information signal and a plurality of second synchronization signals each having a position information signal and a synchronization information signal each representing at least the position of the first synchronization signal, An information signal transmission system characterized in that a predetermined amount of information signals transmitted together with a signal or transmitted as described above is restored based on at least the second synchronization signal.