JPH0653925A - Digital auxiliary signal transmission system - Google Patents

Abstract

PURPOSE:To improve the transmission quality of a digital auxiliary signal, and to reduce a circuit scale and cost by multiplexing a digital auxiliary signal inputted from an outside on a main signal with a main signal synchronized with the frequency of the main signal side. CONSTITUTION:A device 1 for a transmission terminal multiplexes a digital auxiliary signal 10 by synchronizing with the frequency of a main signal 11 side, and transmits it to a reception terminal device 2a in an intermediate repeater station. The device 2a divides the signal between signals 11 and 10, outputs the signal 11 to a transmission terminal device 2b for the intermediate repeater, and outputs the signal 10 to a synchronizing circuit 3. The synchronization-converted signal 10 is multiplexed on the signal 11 by the device 2b, and outputted to a reception terminal 4. The device 4 separates the signal 10 from the multiplexed signal, synchronization-converts the signal 10 into an original transmitting speed, and outputs it through a synchronizing separator circuit 5 to the outside. Thus, it is not necessary to repeatedly operate the synchronization of the signal 10 by a stuff synchronization system, low frequency jitters can be decreased, and the scale of the entire circuit can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital radio system using an intermediate relay station composed of two terminal station devices, and more particularly to improving the transmission quality of a digital auxiliary signal and reducing the circuit scale and system. The present invention relates to a digital auxiliary signal transmission system capable of reducing the cost of the.

[0002]

2. Description of the Related Art A conventional digital auxiliary signal transmission system using an intermediate relay station composed of two terminal stations is
As shown in FIG. 2, the digital auxiliary signal multiplexed and transmitted to the main signal is once separated between the intermediate relay stations and then multiplexed again.

That is, the synchronizing circuit 100 to which the digital auxiliary signal 10 is input is
Is synchronously converted to the transmission speed of the transmission line of the device 1 for transmitting terminal station,
Output to the transmitting terminal device 1. The transmitting terminal station device 1 synchronously multiplexes the digital auxiliary signal 10 with the main signal and outputs it to the intermediate relay station 200.

In the intermediate relay station, the digital auxiliary signal 1 from the multiplexed signal is received at the receiving terminal station device 201 for the intermediate relay station.
0 is separated, and then the digital auxiliary signal 10 is synchronously converted by the synchronous separating circuit 202, and further, the synchronizing circuit 20
In step 3, the digital auxiliary signal 10 is synchronously converted again to the transmission speed of the transmission line of the intermediate relay station transmitting terminal station device 204 and output to the intermediate relay station transmitting terminal station device 204. The transmission terminal station device for intermediate relay station 204 multiplexes the input digital auxiliary signal 10 with the main signal 11 to receive the device for receiving terminal station 4
To transmit. The receiving terminal device 4 separates the digital auxiliary signal 10 from the multiplexed signal and outputs it to the synchronizing circuit 5, and the synchronizing circuit 5 synchronously converts the digital auxiliary signal 10 to the original transmission rate and outputs it to the outside. Output to.

[0005]

Generally, a system in which the digital auxiliary signal 10 is synchronously converted to a transmission speed slightly higher than that of the main signal and sent out on the transmission line is called a stuff synchronization system. In the auxiliary signal transmission method, before the transmission of the intermediate relay station 200 and inside the intermediate relay station 200, the digital auxiliary signal 10 is synchronously multiplexed twice by the stuff synchronization method. But,
When this stuff synchronization method is repeated, low frequency jitter increases, and there is a problem that the transmission quality of the digital auxiliary signal is impaired.

Further, in order to repeatedly perform the stuff synchronization method, it is necessary to provide a synchronization circuit and a synchronization separation circuit for the same amount, which increases the scale of the entire circuit and
There were problems such as the system becoming expensive.

The present invention has been made in view of the above-mentioned problems, and a digital auxiliary signal transmission system capable of improving the transmission quality of a digital auxiliary signal and reducing the circuit scale and the system cost. For the purpose of providing.

[0008]

In order to achieve the above object, the digital auxiliary signal transmission system of the present invention is a digital radio transmission system using an intermediate relay station composed of two terminal stations. Specifically, a device for a transmitting terminal station that multiplexes and transmits the input digital auxiliary signal in synchronization with the frequency of the main signal side, and a signal from this transmitting terminal station device are received, and the digital auxiliary signal is separated and output. An intermediate relay station receiving terminal device, and a synchronizing circuit that inputs the digital auxiliary signal from the intermediate relay station receiving terminal device and outputs the signal in synchronization with the transmission speed of the intermediate relay station transmitting terminal device, A digital auxiliary signal from the synchronizing circuit is input, and a transmission terminal station device for an intermediate relay station that multiplexes and transmits the main signal, and a signal from the transmission terminal station device for the intermediate relay station is received and digitally compensated. A device for receiving terminal station for separating output signals, and digital auxiliary signal input from the reception terminal unit, and has a structure in which and a sync separation circuit for converting synchronization with the original transmission rate.

[0009]

According to the digital auxiliary signal transmission system of the present invention having the above-described structure, the digital auxiliary signal inputted from the outside is multiplexed by the transmitting terminal station device into the main signal in synchronization with the frequency of the main signal side. Therefore, the synchronous conversion process of the digital auxiliary signal before the transmission of the intermediate relay station and the circuit for performing the process can be omitted.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the digital auxiliary signal transmission system of the present invention will be described below with reference to FIG. Figure 1
FIG. 3 is a block diagram showing a digital auxiliary signal transmission circuit according to the present embodiment.

In the figure, reference numeral 1 is a device for a transmitting terminal station. An intermediate relay station 2 is composed of an intermediate relay station receiving end station device 2a, an intermediate relay station transmitting end station device 2b, and a synchronization circuit 3. Here, the transmission terminal station device 2b for the intermediate relay station has an overhead bit transmission line whose transmission speed is slightly higher than the transmission speed of the digital auxiliary signal 10.
Reference numeral 5 denotes a receiving terminal device, which is connected to the sync separation circuit 6.

Next, the operation of the digital auxiliary signal transmission system of the present embodiment having the above configuration will be described. First, the transmission terminal station device 1 multiplexes the digital auxiliary signal 10 input from the outside in synchronization with the frequency of the main signal 11 side, and the multiplexed signal is transmitted to the intermediate relay station reception terminal station device 2a. To transmit.

The receiving terminal station device 2a for the intermediate relay station receives the multiplexed signal, and outputs the main signal 11 and the digital auxiliary signal 1
Separate to zero. Then, the main signal is output to the transmission terminal station device 2b for the intermediate relay station, and the digital auxiliary signal 10 is output to the synchronization circuit 3. The synchronizing circuit 3 receives the digital auxiliary signal 10 and synchronously converts it to the transmission rate of the overhead bit transmission line of the intermediate relay station transmitting end station device 2b, and then outputs it to the intermediate relay station transmitting end station device 2b.

The transmission terminal station device 2b for the intermediate relay station multiplexes the input digital auxiliary signal 10 with the main signal 11 and outputs it to the device 4 for the reception terminal station. The receiving terminal device 4 separates the digital auxiliary signal 10 from the input multiplexed signal and outputs it to the synchronizing circuit 5. The synchronizing circuit 5 synchronously converts the input digital auxiliary signal 10 to the original transmission rate and outputs it to the outside.

According to the digital auxiliary signal transmission system of the present invention having such a configuration, the low frequency jitter is reduced without repeating the synchronization of the digital auxiliary signal by the stuff synchronization system. That is, the transmission quality of the digital auxiliary signal is improved. Further, as compared with the conventional digital auxiliary signal transmission system, the number of synchronization circuits and synchronization separation circuits is reduced, so that the scale of the entire circuit is reduced and the system is inexpensive.

[0016]

As described above, according to the digital auxiliary signal transmission system of the present invention, the transmission quality of the digital auxiliary signal can be improved, and the circuit scale and system cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a digital auxiliary signal transmission system of the present invention.

FIG. 2 is a block diagram showing a digital auxiliary signal transmission system according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Device for transmitting terminal station 2 ... Intermediate relay station 2a ... Device for receiving terminal station for intermediate relay station 2b ... Device for transmitting terminal station for intermediate relay station 3 ... Synchronization circuit 4 ... Device for receiving terminal station 5 ... Sync separation circuit

Claims (1)

[Claims] 1. In a digital radio transmission system using an intermediate relay station composed of two terminal station devices, for a transmitting terminal station for multiplexing and transmitting an input digital auxiliary signal in synchronization with a frequency of a main signal side. Device and a receiving terminal station device for an intermediate relay station that receives a signal from the transmitting terminal device and separates and outputs a digital auxiliary signal, and inputs a digital auxiliary signal from the receiving terminal device for an intermediate relay station, A synchronizing circuit for outputting in synchronization with the transmission speed of the transmitting terminal device for the intermediate relay station, and a transmitting terminal station for the intermediate relay station for inputting the digital auxiliary signal from the synchronizing circuit and for multiplexing and transmitting to the main signal. A device, a device for a receiving terminal that receives a signal from the transmitting terminal device for an intermediate relay station, and separates and outputs a digital auxiliary signal, and a digital auxiliary signal from the device for a receiving terminal are input. A digital auxiliary signal transmission system, comprising: a sync separation circuit that synchronously converts the original transmission speed and outputs.