JPS6393238A - Electronic exchange - Google Patents

Abstract

PURPOSE:To change the number of switching lines of a time division switch in accordance with the increase or the reduction of traffic by providing a band compressing part between an A/D converting part and a code multiplexing part and providing a band expanding part between a multiplex signal separating part and the A/D converting part and issuing a command from a control part to change the compression rate. CONSTITUTION:If m<q<=2m ((m) is the number of lines and (q) is the number of calls) is satisfied because of the slight increase of traffic, the command is issued from a control part 180 to band compressing parts 120-122 and band expanding parts 160-162 so that signals of 64kbps are band-compressed into the signals of 32kps. As the result, m-number of lines among P-number of lines as subscriber's lines are prevented from being busy, and the voice distinction or the like is not very degraded. In case of 2m<q<=4m, the command is issued from the control part 180 to band compressing parts 120-122 and band expanding parts 160-162 so that signals of 64kbps are band-compressed into the signals of 16kbps.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a time division type electronic switching system, and more particularly to a device in which the number of switching lines can be varied by utilizing band compression technology.

(Prior art) Conventionally, this type of electronic exchange has an A/D switch as shown in Figure 2.
Conversion units 210 to 212 and D/A conversion units 270 to 27
2, a subscriber line interface section 200, a code multiplexing section 230, and a time slot converting section 240.
, a multiplex signal demultiplexing section 250, and a control section 280.

The number of subscriber signal lines is assumed to be two lines, and the highway speed is assumed to be N k bps. Generally one analog signal is A
/D conversion requires a speed of 64 k bps, and generally highway speeds are limited by hardware, and due to the need to effectively utilize highways, Nk bps/64 k bps<P.

Therefore, when traffic increases, the highway becomes full and the exchange becomes busy.

(Problems to be Solved by the Invention) In the conventional electronic exchange described above, the capacity of subscriber lines is greater than the number of lines that can be multiplexed in the code multiplexing unit, so it becomes busy during times when traffic increases. It has the disadvantage of becoming

An object of the present invention is to provide a band compression section between an A/D conversion section and a code multiplexing section in an electronic exchange, and at the same time to provide a band expansion section between a multiplexed signal separation section and an A/D conversion section. To provide an electronic exchange which eliminates the above-mentioned drawbacks by issuing a command to change the compression ratio from a control section in a multi-digit exchange, and which is configured so that it does not become busy even when traffic increases. It is in.

(Means for Solving the Problems) The electronic exchange according to the present invention includes a subscriber line interface section, a band compression section, a code multiplexing section, a time slot conversion section, a multiplex signal separation section, and a band expansion section. , and a control section.

The subscriber line interface section includes an A/D conversion section and a D/A
It consists of a converter.

The band compression section is for compressing the output signal of the A/D conversion section.

The code multiplexing section is for multiplexing the outputs of the band compression section.

The time slot conversion section is for converting the time slot of the output signal of the code multiplexing section.

The multiplex signal separation section is for separating the output of the time slot conversion section for each subscriber line.

The band expansion section is for returning the compressed signal to a predetermined signal.

The control section is for instructing the band compression rate of the band compression section and the content of time slot conversion of the time slot conversion section.

(Example) Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of an electronic exchange according to the present invention. In FIG. 1, 100 is a subscriber line interface section, 110 to 112 are A/D conversion sections, 120 to 122 are band compression sections, 130 is a code multiplexing section, 140 is a time slot conversion section, 150
160 to 162 are band expansion units, 170 to 172 are D/A conversion units, and 180 is a control unit.

In FIG. 1, a subscriber line interface unit 100 includes A/D converters 110 to 112 and D/A converters 170 to 1.
72. Band compression sections 120 to 122
Based on the command from the control unit 180, the band expansion units 160 to 162 convert the audio signal converted into PCM to 64 kbps into, for example, 32 kbps and 16kbp.
It has the function of compressing the band to s and then expanding the band.

The code multiplexer 130 synthesizes the output signals of the band compressors 120 to 122 and sends it to the independent signal line 190, and the time slot converter 140 converts the time slot in accordance with the command from the controller 18G. . Further, the multiplex signal demultiplexer 150 performs the opposite operation to the code multiplexer 130, and demultiplexes the multiplex signal of the highway signal [90] and sends it to the band expanders 160 to 162.

Assuming that the maximum speed on the highway signal line 190 is N kbps, m times a (= N k bps / 64 k bps
), the electronic exchange shown in Figure 1 would be
The exchange has a sufficiently larger subscriber line capacity of two lines than m lines. Out of the two subscriber lines, calls occur on nine lines, and no particular band compression is performed when q≦m (normal traffic condition).

However, if the traffic increases a little and m<q≦2m, the control unit 180 instructs the band compression unit 1 to band compress the 64 k bpa signal to a 32 k bps signal.
Commands are issued to the band extension units 20 to 122 and the band expansion units 160 to 162.

As a result, it is possible to avoid busy traffic on line m of the two subscriber lines, and the voice intelligibility is not significantly degraded.

Similarly, if 2m<964m, 64k bp
In order to band-compress the s signal to a 16k bps signal,
The control section 180 issues commands to the band compression sections 120 to 122 and the band expansion sections 160 to 162.

In the above method, the control unit 180 issues a command to change the band compression ratio for all subscriber lines at the same time. On the other hand, when the traffic increases as shown in K and q〉m, it is important to rank the importance of each of the two subscriber lines. It is also possible to perform band compression only on subscriber lines with low bandwidth.

(Effect of the invention) As explained above, the present invention provides an A/
In the r4 configuration, which includes a band compression unit between the D conversion unit and the code multiplexing unit, and a band expansion unit between the multiplex signal separation unit and the D/A conversion unit, the compression ratio is determined by the control unit. By issuing a command to change the number of circuits flowing on the highway signal line, it is possible to change the number of circuits flowing on the highway signal line, and the number of circuits exchanged in the time division switch can be changed in response to increases and decreases in traffic. be.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of an electronic exchange according to the present invention. FIG. 2 is a block diagram showing an example of a conventional electronic exchange. 100.200... Subscriber line interface units 110 to 112, 21 (1 to 212... A/D conversion units 120 to 122... Band compression unit 130.230... Code multiplexing unit 140.240 ...Time slot converter 150.2
50... Multiplex signal separation section 160-162... Band expansion section 17Q-172, 270-272... D/A conversion section 180.280... Control section 190.29()... Highway signal Line Patent Applicant NEC Corporation Agent Patent Attorney Hisashi Inoro 21 Figures 2 Figures

Claims (1)

[Claims] a subscriber line interface section consisting of an A/D conversion section and a D/A conversion section; a band compression section for compressing the output signal of the A/D conversion section; and a band compression section for multiplexing the output of the band compression section. a code multiplexer, a time slot converter for converting the time slot of the output signal of the code multiplexer, and a multiplex signal demultiplexer for separating the output of the time slot converter for each subscriber line. a band expansion section for returning the compressed signal to a predetermined signal; and a control section for instructing the band compression rate of the band compression section and the content of time slot conversion of the time slot conversion section. An electronic exchange characterized by comprising: