JPS6046861B2 - Digital transmission relay method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital transmission repeating system in which a two-wire transmission line can be used as a four-wire digital subscriber line and can compensate for attenuation in the line.

Conventionally, voice signals have been transmitted as analog signals over 2-wire subscriber lines, or in the case of 4-wire systems, hybrid transformers have been used in the exchange, or 2-wire subscriber lines have been abandoned from the beginning and 4-wire subscriber lines have been transmitted. It had disadvantages such as the need to install wire subscriber lines, the reduction in the number of transmission lines which could not be ignored, and the need for repeating and amplification.

Therefore, an object of the present invention is to provide a digital transmission relay system that can convert a two-wire transmission line to four digital lines with a simple configuration.

In order to achieve such an object, the present invention provides a signal detection device that detects a start signal such as a downlink synchronization signal sent from a main station and sends out a start signal, and after receiving this start signal, an uplink relay amplification period pattern generator that sends out a control signal after a delay time T required for the start signal and the subsequent downlink main information to pass; a relay amplification direction switching control device that sends out a switching signal; and a relay amplification direction switching control device that operates upon receiving this switching signal and switches the uplink information from the slave side relay transmission line to the master station side relay transmission line via the upstream side relay amplifier. At the same time, a relay amplifier consisting of a switching device for disconnecting the signal detection device from each width L transmission line is provided in the two-wire transmission line.
It enables wire-type digital relay amplification, and will be explained in detail below using an example.

FIG. 1 is a block diagram showing an embodiment of the digital transmission relay system according to the present invention.

In the figure, 1 and 2 are the master station and slave station, respectively.
3 and 4 are a master station transmitter and a slave station transmitter, respectively;
5 and 6 are a master station receiving section and a slave station receiving section, respectively; 7
and 8 are a master station transmission/reception control unit and a slave station transmission/reception ho 1 control unit, respectively, 9 and 10 are a master station main device and a slave station main device, respectively, and 11 is a downlink synchronization signal 12 as shown in FIG.
A two-wire transmission line 16 is a two-wire transmission line on which downlink information 14 consisting of downlink main information 13 and uplink information 15 are alternately and periodically transmitted, as shown in FIG. One or more relay amplifiers are provided in the middle.

In the relay amplifier 16 shown in FIG. 3, 17 and 18 are a main station side relay transmission line and a slave side relay transmission line, respectively, 19 and 20 are an upstream side relay amplifier and a downstream side relay amplifier, respectively, and 21 and 22 are respectively, A switching device 23 is a signal detection device that sends out a start signal when it detects a downward synchronization signal or a start signal, and 24 is a delay time T after receiving the start signal from the signal detection device 23 (see FIG. 4). After that, the uplink relay amplification period pattern generator 25 sends out a control signal, and receives the control signal from the uplink relay amplification period pattern generator 24, and receives the control signal from the uplink relay amplification period pattern generator 24, and performs a relay amplification direction switching control that switches the switching devices 21 and 22. It is a device.

Next, the operation of the digital transmission relay system according to the above configuration will be explained.

First, the main station transmitter 3 periodically transmits a downlink synchronization signal, signal 12.
(See Figure 2).

For example, when targeting a telephone exchange system, the ΔM modulation and demodulation method uses 36KHz sampling and a period of approximately 27μSe.
In the PCM modulation and demodulation method, the sampling period is approximately 125 μSec at 8 KHz. And that download synchronization! 12, downstream main information (sampled audio data, etc.) is transmitted from the main station 1 to the slave station 2. Note that when there is no information to be transmitted in the downlink direction, only the downlink synchronization signal 12 is periodically transmitted. In addition, the slave station transmission/reception control unit 8 of the slave station 2 detects the arrival of the downlink 5 synchronization signal 12, receives the downlink main information, and transfers it to the slave station reception unit 6, at the same time there is a delay time enough to fully receive the downlink information 14. T(
Delay) (see FIG. 4), and under its control, upstream information 15 is sent from the slave transmitter 4 to the two-wire transmission line 11 via the slave transmitter/receiver controller 8. and main station 1
The upstream information 15 that has arrived is controlled by the main station transmission/reception control section 7 and transferred to the main station reception section 5. Then, signal attenuation on the two-wire transmission line 11 is compensated for by the upstream relay amplifier 19 or the downstream relay amplifier 20 of the relay amplifier 16. That is, the signal detection device 23 detects the downlink synchronization signal 12 sent from the main station 1 and sends a start signal to the uplink relay amplification period pattern generator 24. For this reason,
After receiving the activation signal, this uplink relay amplification period pattern generator 24 generates a synchronization signal 12 as shown in FIG.
The delay time Td required for the and downlink main information 13 to pass
After elay, a control signal is sent to the relay amplification direction switching control device 25.

Therefore, the relay amplification direction switching control device 25 operates, and the time during which the upstream information 15 passes, that is, the time Tup (fourth
(see figure), the switching devices 21 and 22 are switched. Therefore, the upstream information 15 is sent via the path of the slave side relay transmission line 18, the switching device 22, the upstream side relay amplifier 19, the switching device 21, and the master station side relay transmission line 17. Note that during the above time Tup, the signal detection device 23 is disconnected from each relay transmission path 17, 18 by the switching device 21, and the uplink information 15 is not applied to the signal detection device 23, so the above control is incorrect. It is done without any trouble.

FIG. 5 shows another block diagram of the repeater amplifier 16 shown in FIG. 3, in which one switching device 26 and one repeater amplifier 2
7 is provided.

It goes without saying that the operation is the same as in FIG. 3.

Although the switching devices 21 and 22 are shown as relay contacts in the above, they are generally made of semiconductor elements.

In addition, in the above explanation, it was assumed that the signal from the master station 1 is always given periodically, but this is because the target is digitalized audio information. It can also be applied to periodic or non-periodic digital transmission relay systems that return . As explained above in detail, according to the digital transmission relay system according to the present invention, switching between upstream and downstream directions can be performed reliably and stably, so that a 2-wire transmission line can be used as a 4-wire digital transmission. I can do it.

Furthermore, it has the advantage that it can be applied to distances where signal reduction is a problem.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the digital transmission repeating system according to the present invention, Fig. 2 is a flow chart of signals on the two-wire transmission path shown in Fig. 1, and Fig. 3 shows details of the repeating amplifier shown in Fig. 1. FIG. 4 is a diagram showing the relationship between the signal flow on the two-wire transmission path and the upstream relay amplification period to explain the operation of FIG. 3, and FIG. 5 shows the relationship between the relay amplifier shown in FIG. FIG. 2 is a detailed block diagram illustrating an example. 1...Main station, 2...Slave station, 3...Main station transmitting section, 4...Slave station transmitting section, 5...Main station receiving section, 6 ...Slave station receiving section, 7...Main station transmission and reception control section, 8...Slave station transmission and reception MD control section, 9
...Master station main device, 10...Slave station main device, 11...2-wire transmission line, 12...Downlink synchronization signal, 13...・Descent main information, 14...
・Down information, 15... Up information, 16...
... Relay amplifier, 17 ... Main station side relay transmission line, 1
8... Slave side relay amplifier, 19... Upstream side relay amplifier, 20... Downstream side relay amplifier,
21 and 22...Switching device, 23...Signal detection device, 24...Uplink relay amplification period pattern generator, 25...Relay amplification direction switching control device, 26...Switching device, 27...Relay amplifier.

Claims (1)

[Claims] 1 A signal detection device that detects a start signal sent from the main station and sends out a start signal, and a delay time T required for the start signal to pass from the start signal to the subsequent downlink main information after receiving the start signal. an uplink relay amplification period pattern generator that later sends out a control signal; a relay amplification direction switching control device that operates in response to the control signal and sends out a switching signal during a time period during which uplink information passes; and a relay amplification direction switching control device that receives the switching signal. a switching device that operates to switch the upstream information from the slave side relay transmission line to the main station side relay transmission line via the upstream side relay amplifier, and disconnects the signal detection device from each of the relay transmission lines. A digital transmission relay system characterized in that a relay amplifier is provided in a two-wire transmission line to perform four-wire digital relay amplification.