JPS6339199B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a time-division channel device, and more particularly, to a time-division channel device that connects lines without delaying speech signals.

A time-division channel device generally has a time switch for exchanging time slots, a so-called T switch, a space switch for exchanging highways, a so-called S switch, and a junker highway connecting these switches. Digital speech signals passing through the channel equipment are subject to a delay of several frames.

FIG. 1 is a diagram showing an example of a known time-division channel device. In the figure, S is a telephone, LC is a subscriber circuit, AL is an analog circuit, TRK is an analog line trunk, DL is a digital line, DT is a digital trunk, and SM is a switch module, where a multiplexer is installed. MPX,
Forward channel memory SPMF, spatial switch
A channel control device SPC controlled by the SSW, backward channel memory SPMB, demultiplexer DMPX, and main processor MPR is provided, as well as a time slot counter T-CTR and a channel holding memory HM. The forward communication path memory SPMF is written using the output information of the time slot counter T-CTR as an address, and read out using the information read from the communication path holding memory HM as an address, and operates as a forward time switch. Further, information read out from the communication path holding memory HM is written into the backward communication path memory SPMB as an address, and the time slot counter T
- Reading is performed using the output information of CTR as an address, and operates as a backward time switch. The channel shown in FIG. 1 has a T-S-T configuration.

The analog call signal sent from the telephone S via the subscriber line SL is sent to the subscriber circuit LC.
In addition, the call signal from the analog trunk line AL passes through a 2-wire 4-wire coupling circuit at the trunk TRK.
The signal is digitized in the encoding circuit and input to the multiplexer MPX. Digital relay line DL
The digital call signal from the terminal is input to the multiplexer MPX via the digital trunk DT.
These digital call signals are multiplexed.
Distribution multiplexed in MPX, incoming highway
It is input to the forward channel memory SPMF via HWF. Here, the time slots are swapped as is known, and the Jankta Highway
It is output to JHW ₁ , and further input to the space switch SSW from the highway.

In the spatial switch SSW, junker highways are swapped without swapping time slots. In this case, if the above-mentioned input call signal is to be output to the junker highway JHW ₂ of this switch module SM, it will be input to the backward call path memory SPMB via the highway, and the time slots will be swapped. The signal is then input to the demultiplexer DMPX via the output highway HWB.

The demultiplexer DMPX separates the time-division multiplexed speech signal input via the output highway HWB and distributes it to predetermined lines. These distributed digital call signals are respectively input to predetermined subscriber circuits, trunks, and digital trunks, and in the subscriber circuit LC and trunk TRK, they are decoded into analog call signals and passed through a 2-wire and 4-wire coupling circuit. , telephone S and analog trunk line
At the digital trunk DT, the digital communication signal is sent to the digital trunk line DL.

In Figure 1, the subscriber line to which the telephone is connected
SL, analog trunk line AL, digital trunk line
There are a plurality of DTs, and arbitrary lines can be connected to each other.

Next, a frame delay experienced by a speech signal in a time-division channel network having a known T-S-T configuration will be explained.

FIG. 4 is a diagram showing an outline of a time-division channel device having a general T-S-T configuration based on the time-division channel device shown in FIG. 1.

The figure shows multiplexers MPX ₁ to MPX _o , forward channel memories SPMF ₁ to SPMF _o , spatial switch SSW, and backward channel memory SPMB _1.
~SPMB _o , Forward Highway HWF ₁ ~
HWF _o , Jankuta Highway JHW ₁₁ ~ _{JHW 1o} ,
JHW ₂₁ ~ JHW _2o , Backward Highway
HWB ₁ ~ HWB _o , demultiplexer DMPX ₁ ~
DMPX _o is shown, and the telephones SA, SB and their respective subscriber circuits LC _a , LC _b are shown.
Others have been omitted.

Telephones SA and SB are assigned time slots T _A and T _B , respectively.

Assuming that the telephones SA and SB are now connected, the communication path network device shown in FIG. 4 operates as follows.

That is, the speech signal sent from the telephone set SA is digitized in the subscriber circuit LC _a , passes through the multiplexer MPX ₁ , and is temporarily stored in the forward speech path memory SPMF ₁ by the time slot _TA of the forward highway HWF ₁ . It is read out at the time slot T _i and is carried to the space switch SSW by the time slot T _i of the junker highway JHW ₁₁ , and is sent to the junker highway JHW _2o via the gate G ₁ controlled to open at the time slot T _i . , and the backward channel memory is reached at the same time slot T _i.
Once written to SPMB _o , read out at time slot T _B assigned to telephone SB,
The signal reaches the subscriber circuit LC _b of the telephone SB via the backward highway HWB _o and the demultiplexer DMPX _o , is decoded into a voice signal, and is received by the telephone SB.

In addition, the call signal sent from the phone SB is
As in the case from the telephone SA above, the subscriber circuit
Digitized by LC _b , multiplexer MPX _o
Forward highway HWF _o 's time slot T _B
It is temporarily stored in SPMF _o , read out at time slot T _j , and transferred to junction highway JHW _1o .
Spatial switch SSW by time slot T _j
It is carried to junkyard highway JHW ₂₁ via gate G ₂ which is controlled to open at time slot T _j , is once written into backward channel memory SPMB ₁ at the same time slot T _j , and is further assigned to telephone set SA. Backward _highway HWB ₁ , demultiplexer DMPX ₁
The signal reaches the subscriber circuit LC _a of the telephone set SA, where it is decoded into a voice signal and received by the telephone set SA.

That is, the communication signal transmitted from the telephone set SA is switched from time slot T _A to T _i in the forward channel memory SPMF ₁ , and switched from time slot T _i to T _B in the backward channel memory SPMB _o , and sent to the telephone set SB. The speech signal received and transmitted from the telephone SB is switched from time slot T _B to T _j in forward channel memory SPMF _o , and further switched from time slot T _j to T _A in backward channel memory SPMB ₁ . and received by the telephone SA.

As is well known, when swapping the time slots of an audio signal as described above, if the signal is swapped with a time slot that appears before the time slot that carried the signal, the signal will be 1.
If a frame is delayed and the signal is replaced with a time slot that appears after the time slot that carried the signal, no frame delay will occur.

FIG. 5 is an explanatory diagram of frame delay of a speech signal in the speech path device of FIG. 4.

FIG. 5 shows that in the communication path device of FIG. 4, when a speech signal is sent from telephone SA to telephone SB, and when it is sent from telephone SB to telephone SA, the frame delay of the speech signal is determined by time slots T _A , T _B ,
This is to explain that T _i and T _j change in various ways depending on the temporal positional relationship on the frame.

In FIGS. 1, 2, 3, and 4, E is the time slot T _A , T _B ,
DA indicates the frame delay of the voice signal sent from telephone SA to telephone SB; DB indicates the temporal positional relationship on the frame of T _i and T _j ;
represents the frame delay experienced by the voice signal sent from the telephone SB to the telephone SA in the direction opposite to the above.

In the case of FIG. 51, the time slots are T _A , T i , T _i ,
In the case where T _j and T _B are arranged in the order, the telephone
The speech signal sent from SA to SB is transmitted from time slot T _A to T _i in forward channel memory SPMF ₁ , and from time slot T A to backward channel memory SPMB _o.
, time slot T _i is switched to T _B , but since the above time slots are arranged in the order of T _A , T _i , T _B , no frame delay occurs as shown in DA in the same figure, but on the contrary, Phone SB to SA
The call signal sent to is transferred from time slot T _B to T _j in forward call path memory SPMF _o .
In addition, in backward channel switch SPMB ₁ , time slot T _j is switched to T _A , so depending on the time position relationship of the time slots, as shown in DB in the same figure, time slot T _B is switched to T _j .
Also, when switching from T _j to T _A , each is delayed by one frame, and the total is delayed by two frames.

In the case of Fig. 52, the time slots are T i , T j , T A , T A , T _i , T _j , T _A ,
If assigned in the order of T _B , then the phone SA
As shown in DA in the figure, the speech signal sent from SB to SB is delayed by one frame when it is switched from time slot T _A to T _i in forward channel memory SPMF ₁ , and is also delayed by one frame when it is switched from time slot T A to T i in forward channel memory SPMF 1 _. time slot T _i
When switching from TB to _TB , there is no delay, but a delay of one frame as a whole. phone sb
As shown in DB in the figure, the speech signal sent from SA to SA is delayed by one frame when it is switched from time slot T _B to T _j in forward channel memory SPMF _o , and is delayed by one frame in backward channel memory SPMB ₁ . From Lottu T _j
When replaced by T _A , there is no frame delay, but a one frame delay as a whole.

In FIG. 5 3 and FIG. 5 4, the arrangement order of the time slots is T _i , T _A , T _j , as shown in E, respectively.
This shows the case of T _B , T _A , T _i , T _B , T _j , and the frame delay DA of the voice signal sent from telephone SA to SB is 1 frame in the case of Fig.
0 frames (no delay) and the phone
Frame delay of audio signal sent from SB to SA
The DB is two frames in the case of FIG. 53, and one frame in the case of FIG. 54.

As shown in FIG. 4, in the communication channel network, in order for a voice signal to reach from one connected telephone to the other, it passes through two communication channel memories, forward and backward, but as mentioned above, time slots T _A , T _B , T _i , and T _j receive a delay of 0 to 1 frame in each channel memory due to the arrangement, resulting in a delay of 0 to 1 frame as a whole.
~2 frames of frame delay.

As explained above, the frame delay of speech signals between telephones has been explained.In connection not only between telephones, but also between telephones and trunks, or between trunks, the speech channel is configured via two speech path memories, forward and backward. Therefore, there is a delay of 0 to 2 frames as between telephones.

A speech channel that is randomly selected when a call occurs (e.g., determined by the above-mentioned time slots T _i and T _j ) and a time slot accommodating position for the incoming and outgoing call (for example, the position of the above-mentioned time slots T _A and T _B ).
The amount of frame delay varies depending on the T-S-
In T's communication path network configuration, a variation in delay of 0 to 2 frames occurs, but in general, current switching systems do not compensate for this variation by software. This is because if software is used as a guarantee, there is a risk of large call losses.

Furthermore, if the communication path network equipment becomes complicated by having the communication path memory (time switch) in a multi-stage configuration (for example, T-T-S-T-T configuration), the absolute amount and variation of the frame delay as described above will increase. also becomes larger.

Figure 2 shows a master station configured with a time division switch.
CO has at least two remote concentrators RLC ₀ and
RLC ₁ and a digital relay line DL ₀ between them.
1 is a block diagram of an example of a conventionally known telephone facility connected by DL ₁ ; FIG.

When subscriber telephone S _{0 of remote line concentrator RLC 0 and} subscriber telephone S ₁ of a different remote line concentrator RLC ₁ are connected and make a call, the call signal from telephone S ₀ is as follows:
Outputs the 2-wire 4-wire line combination circuit H ₀ and digitizes the remote line concentrator RLC ₀ , digital trunk PT _R0 , digital line DL ₀ , digital trunk PT _C0 , master station CO, digital trunk PT _C1 , digital line DL ₁ , digital
It is transmitted via the trunk PT _R1 and the remote line concentrator RLC ₁ , and is converted to analog (decoded) before the 2-line and 4-line line combination circuit _{H 1 .}
to reach the phone S ₁ . The call signal sent from telephone _S1 is transmitted in the same manner, but in reverse.

On the other hand, it is advantageous in terms of manufacturing, maintenance, repair, etc. to use a remote concentrator with the same configuration as the time-division channel device (switch module) of the master station, without using a special channel device. , it is also economically advantageous.

When the remote line concentrator adopts the same time-division channel configuration (for example, T-S-T configuration) as the master station,
Taking the case of a connection between telephones S ₀ and S ₁ as an example, a call signal sent from telephone S ₀ is reflected by the 2-wire 4-wire line coupling circuit H ₁ of the other party's telephone S ₁ and returns to telephone S ₀ . Coming time (round trip delay)
is twice the sum of the delays in the remote concentrators RLC ₀ , RLC ₁ and the master station CO. If this round trip delay exceeds a certain period of time (for example, 3 mS), this is inconvenient because it causes interference in the telephone conversation as a reverberation. It should be noted that similar problems may occur when other digital lines are relay-connected in multiple stages using a time division switch.

The present invention provides a time-division call path device that can transmit the above-mentioned digital call signal without delay between digital trunks, for example, and thereby enables the above-mentioned digital lines to be connected in multiple stages. The purpose is to reduce the above-mentioned round trip delay that occurs.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 3 is a connection configuration diagram of an embodiment of the present invention, and the symbols in the figure indicate the same ones as in FIG. 1. Note that MPXT is a multiplexer that accommodates the outputs of trunk TRK and digital trunk DT.
DMPWT also has trunk TRK, digital
The demultiplexers CONVF and CONVB that separate the inputs to the trunk DT are forward and backward converters, respectively.

In FIG. 3, the switch module SM has the same configuration as the switch module SM shown in FIG. 1, but in the embodiment of the invention shown in FIG. The call signal sending side of the subscriber circuit LC connected to the subscriber circuit LC is accommodated, and the call signal sending side of the trunk TRK, digital trunk DT, which is required to reduce call delay, is accommodated in another multiplexer MPXT. In addition, the demultiplexer DMPX accommodates only the receiving side of the call signal of the subscriber circuit LC connected to the telephone subscriber line SL, and the demultiplexer DMPXT accommodates the call signal of the trunk TRK and digital trunk DT. accommodating the receiving side.

Multiplexer MPX, demultiplexer
There are a plurality of lines accommodated in the DMPX, that is, subscriber lines SL, and these are exchanged and connected in exactly the same way as in FIG. 1. A detailed explanation of this will be omitted.

The communication path device shown in Fig. 3 is a multiplexer.
MPXT, demultiplexer It is now possible to connect two specific trunks (including digital trunks) housed in DMPXT in a fixed manner, and in a way that reduces the delay to the digital call signal transmitted between them. It is configured. Assume now that digital trunks DT ₀ and DT ₁ are a pair connected as described above.

The digital speech signal output from digital trunk DT ₀ is time-division multiplexed with the digital speech signals from other trunks in the multiplexer MPXT and sent to the forward converter.
Enter CONVF.

Here, Jyankuta Highway JHW ₁ ,
If JHW ₂ multiplexes n-channels, most of these n-channels are allocated for exchanging subscriber lines such as telephone S (lines accommodated in multiplexer MPX), and one of the n-channels is A relay line (line housed in the multiplexer MPXT) as a delay-free channel that does not cause frame delay.
Allocate for use.

The speech signal output from the above-mentioned trunk line (including DL ₀ and DL ₁ ) whose output side is accommodated in the multiplexer MPXT is multiplexed by the above-mentioned multiplexer MPXT and input to the forward converter, and the forward converter CONVF converts each channel. Fixed conversion to the Jankuta Highway JHW ₁ channel is performed so as not to cause frame delay. For example, the channel _{P 0 of} Jankta Highway JHW ₁ is fixedly assigned to the digital trunk DT 0, and the channel P ₁ is fixedly assigned to the digital trunk DT ₁ .

The forward converter CONVF is provided with a buffer memory that temporarily stores the multiplexed input speech signals from the multiplexer MPXT. This buffer memory stores one call signal during one time slot. For example, after the call signal in one time slot of digital trunk DT ₀ is written to the buffer memory, it is read out in the time slot corresponding to channel P ₀ of junker highway JHW ₁ . Channel Jankuta Highway
Send to channel P ₀ of JHW ₁ . Thereafter, a call signal from another line is written into the buffer memory, and similarly the fixedly assigned channel is read out at the time slot corresponding to the channel of Junctor Highway JHW ₁ . digital trunk
The same applies to DT ₁ . multiplexer
MPXT to Forward Converter CONVF
Since the number of channels input to JHW 1 is smaller than that of Janctor Highway JHW ₁ , the above channel conversion is possible without causing frame delay.

The above channels P ₀ and P ₁ , together with other channels, are output to the junker highway JHW ₂ via the spatial switch SSW, and are connected to the backward communication path memory SPMB and the forward converter CONVB.
Enter. The communication signals of channels P ₀ and P ₁ are controlled not to be written to the backward communication path memory SPMB, and
CONVB performs the inverse conversion to that performed by the forward converter CONVF, converts channels P ₀ and P ₁ into channels to digital trunks DT ₁ and DT ₀ , respectively, and outputs them to the demultiplexer DMPXT. . The demultiplexer DMPXT separates the channels and outputs the speech signal carried by each channel to a predetermined trunk. In the above case, the speech signal carried by channel P ₀ goes to digital trunk DT ₁ ;
Also, the speech signal carried by channel P ₁ is carried to digital trunk DT ₀ , and digital trunks DT ₀ and DT ₁ are in a connected state.

In this state, the digital trunk DT ₀ to
The speech signal transmitted to DT ₁ is stored in both forward and backward speech path memories SPMF and
Since it does not go through the SPMB, there is no delay. If it is delayed, only one of the two channels connecting the two digital trunks will be delayed by one frame.

In the above, the digital trunks DT ₀ and DT ₁ have been described as two specific trunks, but any two trunks can be selected as a set and communication signals between them can be transmitted without delay.

In addition, multiplexer MPXT, forward and backward converter CONVF,
Auxiliary switch module SMA with CONVB, demultiplexer DMPXT, and other necessary circuits
If configured, it is possible to configure the time division communication path device of the present invention by adding the switch module SMA to a normal switch module SM.

The present invention is not limited to the above embodiments, and various modifications are possible.

The time division communication path is not limited to the T-S-T configuration described above, but can be easily implemented in other configurations using time switches and space switches.

It goes without saying that the trunks that need to be connected to subscriber lines are housed in the Switch Module SM. Alternatively, by installing a changeover switch between the trunk and the switch module SMA and selectively connecting the trunk to the switch module SM or the auxiliary switch module, it is possible to connect the trunks without delay as described above. , a normal connection of the trunk to the subscriber line can also be made.

Since the present invention is configured as described above,
This has the effect of providing a time division communication channel device that can transmit communication signals between two specific trunks without giving any delay.

Therefore, in the telephone facility shown in Figure 2, the main station
The CO is equipped with a time division communication path device according to the present invention,
Two digital trunks DT _C0 of master station CO,
As explained in the above embodiment, by connecting DT _C1 with a delay-free path that passes through the master station CO, the round trip delay that occurs when telephone S ₀ is connected to telephone S ₁ can be eliminated by connecting DT C1 to the master station CO. It is possible to reduce the delay by the amount of the delay, that is, to reduce it by 1/3, and it is possible to reduce and eliminate the disturbance of the call due to the echo. Note that the present invention is not limited to the connection state shown in FIG. 2, but can be applied to relay connections of digital lines in multiple stages, and similar effects can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a connection configuration diagram of an example of a conventional time-sharing channel device, FIG. 2 is a diagram showing an outline of a telephone exchange facility having at least two remote concentrators, and FIG. 3 is an embodiment of the present invention. 4 is a connection diagram of a general T-channel system based on the time-division channel device shown in FIG. 1.
FIG. 5 is a diagram showing an outline of a conventional time-division channel device having an ST configuration. FIG. 5 is an explanatory diagram of a frame delay of a speech signal in the channel device of FIG. 4. S, S ₀ , S ₁ ... subscriber telephone, SL ... subscriber line, AL ... analog trunk line, TRK ... trunk, DL, DL ₀ , DL ₁ ... digital trunk line,
DT, DT ₀ , DT ₁ , DT _R0 , DT _R1 , DT _C0 , DT _C1 ...
...Digital trunk, MPX, MPXT...Multiplexer, SPMF...Forward channel memory, SPMB...Backward channel memory,
SSW……Space switch, T-CTR……Time switch
Slot counter, HM...channel maintenance memory, SPC...channel control device, MPR...main processor, SM...switch module, SMA
...Auxiliary switch module, CONVF...Forward converter, CONVB...Backward converter, RLC ₀ , RLC ₁ ...Remote line concentrator, CO...Master station.

Claims (1)

[Claims] 1. In a time division multiplexed communication path device having a time switch, a space switch, and a junkter highway that connects these switches, a part of the time division multiplexed communication channel on the junka highway is made into a non-delay channel, and One of the delay-free channels is fixedly assigned as a channel for an input speech signal, the speech signal input from the channel is placed on the delay-free channel, and the delay-free channel is transferred to a fixed line different from the above. It is configured to be fixedly assigned to the output call signal channel and to output the call signal input from the fixed line to a fixed line different from the above without going through a time switch (or call path memory). A time division communication path device characterized by: