JPH0117626B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for reproducing a synchronization signal of a digital signal string, and more specifically, a method for reproducing a synchronization signal common to a plurality of digital signal strings that are synchronized with each other. The present invention relates to a synchronization signal regeneration method that performs processing.

2. Description of the Related Art Conventionally, it has been widely practiced in many devices and systems to individually transmit a plurality of mutually synchronized digital signal streams through each channel in a multiplex transmission path and to combine them at a receiving end. However, in this case, a method has been adopted in which a timing signal synchronized with each digital signal train or a synchronization signal is guided to an independent channel and transmitted to the receiving end via this channel.

The synchronization signal regeneration method shown in FIG. 1 is a method that has been employed conventionally. Hereinafter, an overview of the conventional method will first be explained with reference to FIG. In FIG. 1, a device including a synchronizing signal reproducing system is placed at the receiving end, and is composed of a digital signal processing circuit 101 and a synchronizing signal generating circuit 102. Three digital signal strings 1, 2, and 3 are applied to the digital signal processing circuit 101 via independent channels in the transmission path, and digital signal strings 5, 6, and 7 are output from the digital signal processing circuit 101. Ru. Digital signal string 1 corresponds to digital signal string 5, digital signal string 2 corresponds to digital signal string 6, and digital signal string 3 corresponds to digital signal string 7, respectively. Digital signal strings 5, 6, and 7 are signals obtained by processing digital signal strings 1, 2, and 3, respectively. On the other hand, the synchronization signal generation circuit 102
A timing signal 4 is applied to the digital signal train via an independent channel in the same or separate transmission path. The synchronization signal generation circuit 102 generates a synchronization signal 8 from the input timing signal 4 and applies it to the digital signal processing circuit 101. The digital signal processing circuit 101 generates digital signal trains 5, 6, and 7 from the input digital signal trains 1, 2, and 3 and the synchronization signal 8. Therefore, if the transmission path of the timing signal 4 is disconnected for some reason, the digital signal string 1,
Even if signals 2 and 3 are received normally, the synchronization signal 8 is not present, so the digital signal processing circuit 1
01 does not operate normally, and the digital signal strings 5,
6 and 7 cannot be obtained normally, and the reliability of the synchronization signal generation method is low.

An object of the present invention is to form a composite signal from a plurality of mutually synchronized digital signal trains, extract a timing relationship from the composite signal, reproduce a synchronized signal from the timing relationship, and use this signal in a digital signal processing circuit. The objective is to provide a system structured to

In order to achieve the above object, the synchronization signal regeneration method according to the present invention includes a synthesis circuit, a timing extraction circuit, and a synchronization signal generation circuit in addition to a digital signal processing circuit, and processes a plurality of digital signal sequences. It is configured so that it can be used.
As already explained, a digital signal processing circuit receives multiple digital signal streams individually from independent channels in a transmission path, processes these multiple digital signal streams individually, and sends them out again. be. Similar to the digital signal processing circuit, the combining circuit individually receives a plurality of digital signal trains from independent channels in a transmission path, forms a single combined signal synchronized with these digital signal trains, and sends it out. The timing extraction circuit extracts the synchronization timing relationship common to any digital signal string from the output of the synthesis circuit. The synchronization signal generation circuit generates a synchronization signal common to all digital signal trains based on the timing signal obtained from the timing extraction circuit. The digital signal processing circuit processes the input digital signal string using the synchronization signal obtained from the synchronization signal generation circuit. Therefore, when a digital signal string is processed using the invented method, there is a phenomenon that the operation of the digital signal processing circuit becomes incomplete due to disconnection of the timing signal, which occurs in the conventional method. There isn't. Furthermore, even if some of the digital signal strings are disconnected, if at least one digital signal string is received, the synchronization signal can be regenerated from the received digital signal string. Can be done.

Next, the system of the present invention will be explained in more detail with reference to the drawings.

FIG. 2 is a block diagram showing an embodiment of a device for realizing the synchronization signal regeneration method according to the present invention. In FIG. 2, the synchronization signal regeneration method is realized by a digital signal processing circuit 101, a synthesis circuit 201, a timing extraction circuit 202, and a synchronization signal generation circuit 203. The digital signal processing circuit 101 is similar to the digital signal processing circuit employed in the conventional digital signal processing method, and corresponds to the digital signal processing circuit 101 in FIG. Similarly, digital signal strings 1, 2, and 3 input to the digital signal processing circuit 101 in FIG. 2 and the digital signal processing circuit 10
Digital signal strings 5, 6, and 7 obtained from 1 are also similar to the input signal string and output signal string in FIG. 1, respectively. Therefore, also in FIG. 2, digital signal string 1, digital signal string 5,
Digital signal string 2 and digital signal string 6 correspond to each other, and digital signal string 3 and digital signal string 7 correspond to each other. Similar to the digital signal processing circuit 101, the synthesis circuit 201 processes the digital signal strings 1, 1,
2 and 3 are received individually from independent channels within the transmission path. Now, these digital signal sequences 1 and 2
Considering the digital signal strings shown in FIGS. 3a, b, and 3 as examples of FIG. One signal 10 synchronized to 3
(Fig. 3d) is generated. The input terminal of the timing extraction circuit 202 is connected to the output terminal of the synthesis circuit 201 and receives the synthesis signal 10. The timing extraction circuit 202 detects the rising edge of the input composite signal 10 as shown in FIG. Output. The timing signal 11 is applied to the input terminal of a synchronization signal generation circuit 203, and the synchronization signal generation circuit 203 generates a synchronization signal 12 synchronized with the timing signal 11 as shown in FIG. 3f.

As is clear from the above explanation, the synchronizing signal 12 has a pulse period T of the digital signal trains 1, 2, and 3.
It is a signal that is synchronized with the synchronization signal 8 obtained in FIG. 1, and has the same phase relationship and can have the same level relationship as the synchronization signal 8 obtained in FIG. The digital signal processing circuit 101 in FIG.
2, and operates in synchronization with digital signal strings 1, 2,
Process 3. Processed digital signal sequences 5, 6, and 7 are output corresponding to input digital signal sequences 1, 2, and 3, respectively. Therefore, according to the invented synchronization signal regeneration method, if at least one of the input digital signal sequences 1, 2, and 3 is normal, the composite signal 10 provides normal timing information. As a result, the timing extraction circuit 202 and the synchronization signal generation circuit 203 operate normally, so that the synchronization signal 12 can be obtained normally.

According to the method of the present invention, a normal synchronization signal can be obtained as long as the digital signal string to be received is not completely disconnected, so the digital signal processing circuit operates normally. Therefore, the processing can be performed satisfactorily even under the worst conditions. There is.

The synchronization signal reproducing method according to the present invention is applicable to all devices that receive a plurality of digital signal sequences, perform processing using the synchronization signals, and then retransmit them.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a configuration for realizing a conventional synchronizing signal reproducing method, and FIG. 2 is a block diagram showing an embodiment of an apparatus for implementing a synchronizing signal reproducing method according to the present invention. Figure 3 shows the second
FIG. 3 is a waveform diagram for explaining the operation of the circuit shown in the figure. 101...Digital signal processing circuit, 201...
... Synthesis circuit, 202 ... Timing extraction circuit, 2
03...Synchronization signal generation circuit, 1, 2, 3, 5,
6, 7... Digital signal string, 8, 12... Synchronization signal, 10... Combined signal, 4, 11... Timing signal.

Claims (1)

[Claims] 1 In a device including a digital signal processing circuit for receiving and processing a plurality of mutually synchronized digital signal strings and then transmitting the same, the device receives the plurality of digital signal strings individually and processes the plurality of digital signal strings. a synthesis circuit for generating one composite signal synchronized with each of the digital signal sequences; and a timing extraction circuit connected to the synthesis circuit for extracting a timing relationship common to the plurality of digital signal sequences from the composite signal. , a synchronization signal generation circuit connected to the timing extraction circuit for generating a synchronization signal having the timing relationship, and processing the plurality of digital signal strings using the synchronization signal. Synchronous signal reproduction method configured as follows.