JPH098819A - Exchange control system for voice cell - Google Patents

Abstract

PURPOSE: To provide an exchange control system of a voice cell, which avoids the deterioration of voice quality due to the abolishment of the voice cell and the change of a code, by distributing a feed pulse which is generated from a prescribed multiframe pulse and which adjusts the transmission timing of the voice cell to a cell making mechanism for making respective voices into the cell so that the voice cell is arranged in time-division manner in an exchange bus. CONSTITUTION: The feed pulses 51-5N obtained by subdividing the multiframe at equal intervals are sequentially transmitted from the multiframe pulse 5 having transmission intervals to the cell making mechanisms 21-2N forming the digital code of sound received by sound channels 11-1N into the voice cells 60 having prescribed fixed length and transmitting them to an asynchronous time divion switch 40 at the equal intervals. The voice cells 60 generated in the cell making mechanisms 21-2N are transmitted to input lines 31-3N.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice cell exchange control system, and in particular, a predetermined number of digital voices sampled into a PCM code of 8 bits at a sampling frequency of 8 kHz are collected into a fixed length voice cell. The present invention relates to a voice cell exchange control system in which this voice cell is taken out from a cell assembling mechanism and is input to an asynchronous time division switch to perform time division exchange.

[0002]

2. Description of the Related Art Conventionally, this type of voice cell exchange control system converts a 64 Kbps voice code into cells and inputs the cells to an asynchronous time division switch (ATM time division switch) to input voice cells from a plurality of channels. The switching processing is executed by arranging them on one switching bus, and taking out the header of the voice cell on each output line and taking it out.

FIG. 4 is a block diagram showing an example of a conventional configuration for converting a voice code into cells and inputting the cells to an asynchronous time division switch. Further, FIG. 3 is an explanatory diagram schematically showing an example of the structure of a voice cell. Referring to FIG. 3, the voice cell 60
Has a fixed length of 53 octets, and has a 9-octet header added to the cellized voice (= 44 octets) obtained from the voice channel 10.

A conventional example will be described below with reference to FIG. 3 and FIG.

The voice channel 10 is connected to each input line 31 to 3N through the cell assembling mechanism 61 to 6N for each voice channel 11 to 1N of 64 Kbps.

Each of the cell assembling mechanisms 61 to 6N outputs the voice cell 60 to each of the input lines 31 to 3N at a period of 5.5 ms (= 44 [octets] × 125 [μs]). There is no timing coordination between each other.

The asynchronous time division switch 40 includes input lines 31 ...
When a plurality of voice cells 60 input from 3N are input almost simultaneously, these voice cells are discarded. Also, when there is an overlap of voice cells, the code is changed for the first voice cells and the voice cells after are discarded.

[0008] That is, in many cases, it is possible to find out the meaning of voice even if it is discarded or dropped for a short time, and it is only necessary to reduce the sound quality in a time of about several ms. .

Of course, the data cell (5
In the case of a total of 53 bytes (octet) consisting of a byte header and a 48-byte information field), one cell is transmitted on the exchange bus inside the asynchronous time division switch 40 so as not to lose a code. Then, the procedure of transmitting the next cell is taken.

[0010]

As described above, according to the conventional voice cell exchange control method, voice cells formed for each voice channel and requiring transmission at the same cycle are adjusted without timing adjustment between channels. The cell assembling mechanisms 61 to 6N send the asynchronous cells to the asynchronous time division switch 40, so that the voice cells are discarded and the code is changed. Further, since the cell assembling mechanism generally transmits the voice cell at the timing, when the voice cell is discarded or the code is changed, the voice cell may be discarded for a long time and the sound quality is not deteriorated. There was a problem that it was dangerous.

Therefore, an object of the present invention is to solve the above problems and to generate a voice from a predetermined multi-frame pulse in a cellizing mechanism for cellizing voice so that voice cells are time-divisionally arranged on a switching bus. Voice cell exchange that completely avoids problems such as voice cell discard and voice quality degradation due to code change, voice cell delay, and continuous voice cell discard by distributing the send pulse that adjusts cell send timing. To provide a control method.

[0012]

In order to achieve the above object, the present invention is a cell for forming PCM voice sampled into a code of a predetermined number of bits at a predetermined sampling frequency into a voice cell all at once for a fixed length. In the exchange control method of the voice cells for time-division exchange, the voice cells are taken out from the activating mechanism and input to the asynchronous time division type switch, and a multi-spacing that defines an interval for sequentially extracting the voice cells from one cell activating mechanism is used. The frame pulse further has a timing means for generating a further equalized sending-out pulse from the frame pulse and sequentially sending the sending-out pulse to the plurality of cell assembling mechanisms, and the cell-making mechanism receiving the sending-out pulse. In this case, the voice cell is transmitted at a predetermined transmission rate within the transmission pulse interval transmitted by the timing means. To provide the exchange control system.

In the present invention, preferably, the timing means inputs only one of the voice cells to the asynchronous time division type switch at the same time from the plurality of cell assembling mechanisms through a plurality of corresponding input lines. The timing of the sending pulse is controlled so that

[0014]

According to the voice cell exchange control system of the present invention, a plurality of voice cells received on the voice channel are formed into voice cells having a predetermined fixed length and are sent to the asynchronous time division switch at equal intervals. From the multi-frame pulse with this transmission interval, to the cell assembly mechanism, send out one subdivided send-out pulse at even intervals, and sequentially send it, and the voice cells created by each of the cell assembly mechanisms are input to the input line. By sending, voice cells from one input line will arrive from multiple input lines that are input to the asynchronous time division switch at the same time.By receiving voice cells sequentially, the voice cells in the asynchronous time division switch It is possible to prevent a voice cell from being discarded and a code change from occurring due to cell collision and overlap.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block connection diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a time chart showing an example of code transmission on the main connection path in FIG.

Referring to FIG. 1, audio channels 11-1N are
Digitally encoded voices having a code rate of 64 Kbps are connected to the input lines 31 to 3N for inputting to the asynchronous time division switch 40 via the cell assembling mechanism 21, respectively.

As shown in FIG. 1, in this embodiment,
Timing means 50 is further added to the conventional example shown in FIG.

The timing means 50 inputs the multi-frame pulse 5 having a period of 5.5 ms, and if the exchange bus in the asynchronous time division switch 40 has a transmission rate of 10 Mbps, the voice channel for generating a voice cell of 53 octets is 10
[Mbit / s] x 5.5 [ms] / (53 [octets] x 8 [bit])
＝ 10 × 5.5 × 10 ^{3 / (} 53 × 8) ＝ number less than 129.7, eg
44μs (= 5.5ms / 125) for 125 channels
Output pulses 51 to 5N (N = 125) with a cycle are sequentially output.

Referring to FIG. 1 together with FIG. 2, 125 sending pulses 51 to 5N are generated at equal intervals of 44 μs during the 5.5 ms period of the multi-frame pulse 5, and the cell assembling mechanism 21 2N (N = 125) are sequentially driven.

The cell forming mechanism 21 sends the sending pulse 51 to 5.5 m.
When received at s intervals, audio channel 11
The voice cell received and created by the device is transmitted to the input line 31. Similarly, when sending-out pulses 52-5N are received from the cell assembling mechanisms 22-2N, respectively, the voice cells received from the voice channels 12-1N by this time are sequentially sent to the input lines 32-3N.

The voice cells in each of the input lines 31 to 3N are set at 5.5 ms intervals, but the voice cells are transmitted to each other from the input lines 31 to 3N in the forward order by the sending pulses 51 to 5N. The time of transmission to the exchange bus of the division switch 40 is also forwarded, and voice cells on each line do not overlap.

In this embodiment, when one voice cell and a plurality of other voice cells are mixed on the asynchronous time division switch 40, the time slot for transmitting the voice cell is fixed at 5.5 ms cycle. Therefore, it is possible to avoid the collision of the voice cells when transmitting the voice cells.

[0024]

As described above, according to the voice cell switching control system of the present invention, the asynchronous time division switch is formed by forming the digital code of the voice received on the voice channel into the voice cell having a predetermined fixed length. To multiple cellizing mechanisms that send at equal intervals, one multi-frame pulse with this sending interval is further sent to one sending pulse that is further subdivided into even intervals, and each of the cellizing mechanisms sends it. By sending the created voice cells to the input line, one input line will arrive from multiple input lines that are input to the asynchronous time division switch at the same time. By receiving the voice cells sequentially, the asynchronous time division switch In this case, it is possible to prevent the discarding of voice cells and the occurrence of code change due to the overlap of voice cells. According to the present invention, it is possible to prevent deterioration of sound quality due to discarding of voice cells,
Furthermore, it is possible to completely avoid the occurrence of continuous discarding of a plurality of voice cells and to avoid the delay of voice cell transmission.

[Brief description of drawings]

FIG. 1 is a block connection diagram showing an embodiment of a voice cell exchange control system of the present invention.

FIG. 2 is a time chart showing an example of pulses and cells on the main part of FIG.

FIG. 3 is an explanatory diagram showing an example of the structure of a voice cell.

FIG. 4 is a block connection diagram showing an example of conventional voice cell exchange control means.

[Explanation of symbols]

 11 to 1N voice channel 21 to 2N cell formation mechanism 31 to 3N input line 40 switch 5 multiframe pulse 51 to 5N sending pulse 60 voice cell

Claims (2)

[Claims] 1. A non-synchronized time division system in which a voice cell is taken out from a cell forming mechanism for collectively forming PCM voice sampled into a code of a predetermined number of bits at a predetermined sampling frequency into fixed length fixed voice cells. In the voice cell exchange control method of inputting to the switch and performing time-division exchange, from the multi-frame pulse that defines the interval at which the voice cells are sequentially taken out from one of the cell assembling mechanisms, the transmission pulse at equal intervals is further subdivided. Generated, having a timing means for sequentially sending the sending pulse to the plurality of cellizing mechanism, when the celling mechanism receives the sending pulse,
A voice cell exchange control system characterized in that the voice cell is transmitted at a predetermined transmission rate within a transmission pulse interval transmitted by the timing means. 2. The sending pulse so that the timing means inputs only one voice cell at a time from the plurality of cell assembly mechanisms to the asynchronous time division type switch via a plurality of corresponding input lines. 2. The voice cell exchange control system according to claim 1, wherein the timing of the above is controlled.