JPH0541697A - Multiplexing system - Google Patents

Abstract

PURPOSE:To balance the spectrum of a channel by deteriorating the mark rate in a non-communicable state at the time of the nonuse of the channel. CONSTITUTION:Signaling bits SS1, SS2,...SS24 are multiplied with the time slots designated by a transmission signaling signal multiple circuit 3. The use/ nonuse of each channel is detected by a transmission signaling signal detection circuit 2, and the information is sent to a PN pattern insertion circuit 5. Voice PCM signals VS1, VS2,...VS24 of the channel are passed, and an output signal with the mark rate 1/2 of a PN pattern generation circuit is inserted instead of the voice PCM signal of the channel at the nonuse of the channel. Then, it is transmitted as a transmission bipolar signal from a transmission unipolar/ bipolar conversion circuit 7 through a transmission frame multiplexing circuit 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplexing system used for PCM multiplexing of digital telephone devices.

[0002]

2. Description of the Related Art Conventionally, in this type of PCM multiplexer,
The level of the audio signal from the converter is adjusted, the band is limited by the filter, and then converted into the PCM signal shown in FIG. 2 by the encoding circuit.

By the way, in the new PCM-24 system, μ-1a
The encoding method of w is adopted, and the folded binary code is adopted with a companding characteristic of approximating 15 broken lines (μ = 255). As shown in FIG. 2, this encoding method is a folded binary code in which there are many "1" s near the input level "0", the first bit indicates the polarity, and the second to eighth bits indicate the absolute value of the level. It represents.

As described above, "1" is generated near the input level "0".
Because of the use of the folded-back two-inverse sign, there are many non-talking states (input level “0”) due to the characteristics of the telephone voice signal, and the probability of being marked as ALL “1” in the PCM output is high. The ALL "0" pattern is rarely continuous. Therefore, there is an advantage that it is not necessary to perform ALL “0” prohibition operation for extracting the timing of the relay transmission line system.

[0005]

However, in the conventional PCM multiplexer, as shown in FIG. 2, since the folded binary code having many "1" s near the input level "0" is adopted, the telephone Due to the characteristics of voice signals, there are many non-calling states (input level “0”), and the probability of being marked as ALL “1” in PCM output is high. PCM with a digital primary group transmission line (1.5 MBPS) that transmits signals on the AMI code side
When transmitting the output ALL "1", the power of the balanced pair cable becomes large and the crosstalk between adjacent cables (crosstalk)
Is a problem. For this reason, it is difficult to accommodate the lines in all the multi-core balanced-pair cables, and there is a drawback that the line accommodation efficiency of the multi-core balanced-pair cables cannot be improved, and this improvement has been a problem.

Further, there is a scramble system as a method of halving the mark ratio of the transmission line. This scramble system requires a scrambler on the transmission side and a descrambler on the reception side, and a scrambler circuit is required together with the opposite device to apply it to the existing transmission line. If it is used for a transmission line or the like, the scale of the device will increase and the economic burden will be great, making introduction difficult.

It is an object of the present invention to provide a multiplexing system which lowers the mark ratio in the non-communication state when the line is not used and improves the line accommodation efficiency of the multi-core balanced pair cable.

In order to achieve this object, the multiplexing system of the present invention comprises a transmitting side signaling signal detecting circuit for detecting the use or non-use of each channel and a pattern with a mark rate of 1/2. A PN pattern generating circuit to be generated and a pattern with a mark rate of 1/2 from the PN pattern generating circuit is inserted into the time slot of the corresponding channel on the transmitting side when the channel is not used in the signaling signal detecting circuit on the transmitting side, instead of the voice PCM signal. A PN pattern insertion circuit, a transmission side voice PCM signal multiplexing circuit for passing a voice PCM signal of the corresponding channel supplied when using a channel, and a transmission side signaling signal multiplexing for multiplexing signaling bits in designated time slots. Multiplexing circuit, a transmission side frame multiplexing circuit for outputting a multiplexed signal, and a transmission buffer. It is intended and a transmission side unipolar / bipolar conversion circuit for sending a polar signal.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the multiplexing system of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of the embodiment.

In FIG. 1, in this example, a voice PCM signal (VS) of a corresponding channel is supplied when the channel is used.
1, a voice PCM on the transmitting side that allows VS2 ... VS24) to pass through
A signal multiplexing circuit 1, a transmitting side signaling signal detecting circuit 2 for detecting use / unuse of each channel, and a transmitting side signaling signal multiplexing for multiplexing signaling bits SS1, SS2 ... SS24 side by side in designated time slots. And a digitizing circuit 3. Furthermore, the mark ratio 1 /
2, a PN pattern generation circuit 4 for outputting a pattern (signal) of 2, a PN pattern insertion circuit 5 for inserting a pattern with a mark ratio of 1/2 in a time slot, a frame synchronization pulse, a data link bit, an error check bit, SE
Transmission side frame multiplexing circuit 6 for multiplexing ND bits
And a transmission side unipolar / bipolar conversion circuit 7 for transmitting to the opposite device as a transmission bipolar signal.

Next, the operation of this configuration will be described.

The transmission side signaling signal input from the exchange is level-converted in the channel board into signaling bits SS1, SS2 ... SS24, which are multiplexed side by side in the time slot designated by the transmission side signaling signal multiplexing circuit 3. ..

Next, the transmitting side signaling signal detection circuit 2
The use / unuse of each channel is detected by and the information is sent to the PN pattern insertion circuit 5.

In the PN pattern insertion circuit 5, according to the used / unused information of each channel supplied from the transmission side signaling signal detection circuit 2, when the channel is used, the corresponding channel supplied from the transmission side voice PCM signal multiplexing circuit 1 The audio PCM signals (VS1, VS2 ... VS24) are passed, and when the channel is not used, the time is used instead of the audio PCM signals (VS1, VS2 ... VS24) of the corresponding channel supplied from the transmitting side audio PCM signal multiplexing circuit 1. A pattern with a mark ratio of 1/2 of the PN pattern generating circuit 4 is inserted into the slot.

After that, the frame sync pulse, the data link bit, the error check bit, and the SEND bit are multiplexed by the transmitting side frame multiplexing circuit 6, and then transmitted from the transmitting side unipolar / bipolar converting circuit 7 to the opposite device as a transmitting bipolar signal. To be done. On the other hand, there is no special processing on the receiving side, and the PN pattern is inserted in the received unused channel, but it is determined that the unused channel is a signaling bit and the PN pattern is not connected to the exchange.
The pattern has no effect on others.

Thus, instead of the voice PCM signals (VS1, VS2 ... VS24) of the corresponding channel supplied from the transmitting side voice PCM signal multiplexing circuit 1 in the unused channel, the PN pattern is inserted in the time slot. As a result, the mark rate in the non-communication state when the channel is not used is reduced, the spectrum of the channel can be balanced, and the line accommodation efficiency of the multicore balanced pair cable is improved. In this case, the line accommodation rate of the multi-core balanced pair cable in a public telephone line transmission line with many free channels such as in the suburbs is improved, the device scale is reduced, and the economic burden is reduced.

[0017]

As is apparent from the above description, according to the multiplexing system of the present invention, the voice PCM of the corresponding channel supplied from the voice PCM signal multiplexing circuit of the transmitting side is an unused channel.
Since the PN pattern is inserted in the time slot instead of the signal, the mark rate in the non-talking state when the channel is not used decreases, and the channel spectrum can be balanced, and the multicore balanced pair cable line This has the effect of improving the storage efficiency.

In addition, there is an effect that the line accommodation rate of the multi-core balanced pair cable is improved in a public telephone line transmission line with many free channels such as in the suburbs.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a multiplexing system of the present invention.

[Fig. 2] 15 in μ-1aw used for conventional explanation
It is a coding system characteristic view of a polygonal line companding characteristic.

[Explanation of symbols]

 1 Transmitting side voice PCM signal multiplexing circuit 2 Transmitting side signaling signal detection circuit 3 Transmitting side signaling signal multiplexing circuit 4 PN pattern generating circuit 5 PN pattern inserting circuit 6 Transmitting side frame multiplexing circuit 7 Transmitting side unipolar / bipolar conversion circuit

Claims (1)

[Claims] 1. A transmission side signaling signal detection circuit for detecting the use or non-use of each channel, a PN pattern generation circuit for generating a pattern with a mark ratio of 1/2, and a channel unused state in the transmission side signaling signal detection circuit. Sometimes a PN pattern insertion circuit that inserts a pattern with a mark ratio of 1/2 from the PN pattern generation circuit into the time slot of the corresponding channel on the transmission side instead of the audio PCM signal, and an audio PCM of the corresponding channel supplied when the channel is used
Transmitting side voice PCM signal multiplexing circuit for passing signals, transmitting side signaling signal multiplexing circuit for multiplexing signaling bits in a designated time slot, and transmitting side frame multiplexing circuit for outputting multiplexed signals And a unipolar / bipolar conversion circuit on the transmission side that sends out a transmission bipolar signal.