JPH02179041A - Circuit for receiver side of dsi equipment - Google Patents

Abstract

PURPOSE:To utilize a relay line effectively and to eliminate unpleasant noise by adding a means detecting a noise average level for each talking line and a means extracting its output and varying the noise level. CONSTITUTION:A noise level detector 4 finds out a talking line whose connection to a relay line is going to be released by assignment control information from a receiver side assignment control memory 3 and gives a mean value of signal levels detected just before the talking line is interrupted to a level control circuit 7 as a noise level of the talking line. The control circuit 7 acts like decreasing timewise the signal level received from the detector 4 and gives the resulting signal to a random noise generator 5. The generator 5 generates a random noise given to the talking line according to the mean value of the signal levels to be given. Thus, the noise level added from a noise insertion circuit 6 to the talking line is decreased timewise.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention improves the utilization efficiency of PCM telephone lines [Conventional techniques] In the case of a line for telephone calls, the time taken for one call line is The percentage of time in which voice energy exists is generally 40% or less, and if only the section where voice energy exists is effectively transmitted, it is less than the number of connected communication lines M (M is a positive integer). Information can be transmitted using N number of relay lines, and the utilization efficiency of the relay lines can be increased.

This method is called the DSI method and has been put to practical use as a DSI device in satellite lines and the like.

Generally, the transmitting side of the DSI device detects the section where voice energy exists among the 9 call lines, connects the 1 call line and the relay line, and transfers this connection information (hereinafter referred to as 1 call route allocation information) to the relay line. Feed through time slots for q of 1
The r-number of the communication path is sent to the relay line where the assignment is to be made.

On the other hand, on the receiving side of the DSI, the allocation of trunk lines and call lines is determined based on the sent communication route allocation information, and the DSI
The communication path data sent from the transmitting side via the relay line is output to the communication line.

At this time, the relay line has fewer lines than the voice line, so 1
There are always some telephone lines that are not connected to a relay line. Since such a line is completely silent and makes a conversation sound unnatural, generally very low level random noise is inserted.

In addition, in recent years, the noise level existing in the silent section of the communication line on the transmitting side is detected, the noise level is encoded and added to the 4-channel assignment information, and the 2-channel assignment information is decoded on the receiving side and the noise level is added to the 4-channel assignment information. There is also a method in which the level is decoded and held, and when a communication line is disconnected from a trunk line, random noise according to the decoded noise level is inserted into that line.

An example of this conventional method will be explained below with reference to FIG.

FIG. 2 is a block diagram showing an example of a conventional DSI system. In FIG. 2, (A) shows the transmitting side, and (B) shows the receiving side.

1. Referring to FIG. 2, on the transmitting side.

A PCM signal of M (the number of communication lines) lines is inputted to the transmission side input terminal 21 from the transmission side communication line. This input signal passes through the delay circuit 23 and is input to the transmission side high speed switch circuit 24. Further, the I'CM signal inputted to the transmission side input terminal 21 is inputted to the audio detector 25 which detects the presence of audio energy.

One output of this voice detector 25 is input to a transmission side allocation control circuit 26. The other output of the voice detector 25 is input to a noise level detector 27.

The transmission side allocation control circuit 26 allocates communication paths according to the output of the voice detector 25 and sends two communication path allocation information to the transmission side high speed switch circuit 24 and the allocation information encoder 28. The noise level detector 27 detects the average value of the noise level for each line during the time when there is no voice energy on the input communication line, and inputs it to the 2-allocation information encoder 28. Allocation information encoder 28
encodes the communication path allocation information and the noise level of the communication line allocated to the communication path allocation information to create and output one allocation information code. The transmitting side high-speed switch circuit 24 performs 1. Outputs PCM signals of N lines corresponding to the number of relay lines N (N<M, positive integer).

These N-line PCM signals are sent from the output terminal 22 to the trunk line together with the allocation information code output from the allocation information encoder 28.

Referring to FIG. 2(B), on the receiving side, the above N
The line PCM signal and allocation information code are input to the receiving side input terminal 8 from the relay line. Among these, the PCM signal of N lines is input to the receiving side high-speed switch circuit 1, and at the same time, the assignment information code is input to the assignment information decoder 2. decoded to the average noise level of the line. The receiving side allocation control memory 3 is controlled by this decoded channel allocation information, and the receiving side allocation control memory 3 inputs the allocation control information to the receiving side high speed switch circuit 1 and the noise insertion circuit 5. The output of the receiving side high-speed switch circuit 1 is given to the noise insertion circuit 6 as an M-line PCM signal. Furthermore, the average noise level decoded by the allocation information decoder 2 is determined by the random noise generator 5.
The random noise generator 5 generates random noise for each communication path according to this average noise level, and inputs it to the noise insertion circuit 6. The noise insertion circuit 6 refers to the 1-allocation control information and inserts random noise into speech lines to which no trunk line is allocated. The output of the noise insertion circuit 6 is sent as an M-cycle PCM signal from the receiving side output terminal 9 to the receiving side communication line.

[Problem to be solved by the invention]

In this way, according to the conventional technology, the average noise level detected on the transmitting side of the DSI device is encoded and sent to the receiving side of the DSI device using a part of the relay line, which makes effective use of the relay line. There was a drawback that it was not possible.

In addition, the silent sections on the two call lines are relatively long.

Moreover, when the noise level sent from the transmitting side is high, the noise has the disadvantage of becoming annoying.

The object of the present invention is to provide a DSI which eliminates the above-mentioned drawbacks, makes effective use of relay lines, and eliminates annoying noise.
It provides the receiving side circuitry of the device.

[Means for solving problems]

The receiving side circuit of the DSI device according to the present invention is controlled by the received call path assignment information from the relay line input of the number N of lines, and is controlled from the relay line input of the N lines to the call line of M lines (M>N).
), a noise level detector that receives the output of the allocation memory and the output of the communication line and detects the average level of noise for each communication line, and a switch circuit that outputs the output of the noise level detector. a level control circuit that changes the value of a mixed noise level; a random noise generator that generates random noise according to the output of the level control circuit; and a random noise generator that generates random noise that is not allocated to a communication path. A noise insertion circuit inserted into a speech line.

〔Example〕

Next, five aspects of the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a receiving side circuit of a DSI device according to the present invention.

In the present invention, without transmitting noise during no calls from the transmitting side to the receiving side, the receiving side detects the average level of noise from the data of the received PCM line, and detects the noise included in the transmitting side's communication line. I'm getting a no-call noise that's almost equal to the noise I'm getting.

In the receiving side circuit of the DSI device shown in FIG. 1, relay PCM signals of N lines are inputted to the receiving side input terminal 8 from the relay line. Of these, the PCM signals of N lines are input to the receiving side high speed switch circuit 1, and at the same time, the allocation information code in the trunk line is input to the allocation information decoder 2 and decoded into channel allocation information. The receiving side allocation control memory 3 is controlled by this decoded channel allocation information, and the receiving side allocation control memory 3 sends the allocation control information to the receiving side high speed switch circuit 1 and the noise level detector 4. The output of the receiving side high speed switch circuit 1 is given to the noise insertion circuit 6 and the noise level detector 4 as a 1M line PCM signal. Noise level detector 4
The output of is input to the level control circuit 7, and the level control circuit 7
The output of the random noise generator is input to the random noise generator 5, and the output of the random noise generator is input to the noise insertion circuit 6. Insert random noise into the telephone line. The output of this noise insertion circuit 6 is the PCM of M lines.
It is sent as a signal from the receiving side output terminal 9 to the receiving side communication line.

The above is the configuration of an embodiment according to the present invention.

In this embodiment, a noise level detector 4 and a level control circuit 7 are used.
There are characteristics. The characteristics will be explained below.

Generally, a voice detector on the transmitting side of a DSI device detects voice energy by integrating the signal level of an input speech line. However, once the audio is detected,
A very short low-level portion within an audio burst causes the audio detector to conclude that there is no audio energy.
Since unnecessary voice disconnections occur frequently and the intelligibility of the call deteriorates, a hangover period is provided to provide inertia to the voice detector. This hangover time is normally set to a value of 100 milliseconds or more in consideration of the transmission of voice and exchange signals.

Therefore, to the receiving side of the DSI device, N-line PCM signals with hangover time added are sent via the relay line, and even after passing through the receiving side high-speed switch circuit, the hangover time is included in. Also,
The hangover time always exists immediately before the connection between the trunk line of the DSI device and the speech line is disconnected, and most of the PCM data on the speech line that exists during the hangover time has components close to noise.

The noise level detector 4 used in the present invention receives the M communication lines output from the receiving side high-speed switch circuit 1 and the allocation control information output from the receiving side allocation control memory 3, and keeps the PCM signal of 1 communication line constant. The average value of the signal level of each line is detected, and the average value of the signal level of each line is held. On the other hand, the noise level detector 4 also constantly refers to the allocation control information, detects a call line that is about to be disconnected from the trunk line based on the allocation control information, and detects a signal detected just before the call line is disconnected. The average value of the levels is used as the noise level of the communication line and is provided to the level control circuit 7.

The level control circuit 7 operates to temporally reduce the signal level received from the noise level detector 4 and supplies it to the random noise generator 5. The random noise generator 5 generates random noise to be applied to the telephone line according to the average value of the given signal level.

Here, if the average value of the signal level detected just before one call line is disconnected is at least within the hang-up time of the voice detector used on the transmitting side of the DSI, it is input to the transmitting side. This signal level is approximately equivalent to the average level of noise included in the speech line, and since this signal level is controlled to decrease over time, the noise level added to the speech line by the noise insertion circuit 6 is also becomes smaller over time.

〔Effect of the invention〕

As explained above, according to one aspect of the present invention, information on the yl and sound when there is no call is not sent from the transmitting side of the DSI device to the receiving side, and from the PCM line data received only on the receiving side of the DSN device. , detects the average level of noise and obtains a no-call noise that is almost equal to the noise included in the transmitting call line, and since the noise level of the disconnected call line decreases over time, the relay line This has the effect of making effective use of noise and eliminating unpleasant noise.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of a receiving side circuit of a DSI device according to the present invention, and FIG. 2 is a block diagram showing the configuration of a conventional device. 1: Receiving side high-speed switch circuit, 2: Allocation information decoder, 3
; Receiving side assignment control memo IJ t 4: Noise level detector, 5: Random noise generator, 6: Noise insertion circuit, 7 Two-bell control circuit, 8: Receiving side input terminal, 9: Receiving side output terminal, 21 : Sending side input terminal. 22: Transmission side output terminal, 23: Delay circuit, 24: Transmission side high speed switch circuit, 25: Audio detector. 26: Sending side allocation control memo 17, 27: Noise level detector, 28: Allocation information encoder Fig. 1

Claims (1)

[Claims] 1. A means for separating and decoding the channel allocation information from the received relay line input of N lines, an allocation memory for storing the decoded communication path allocation information, and a relay of N lines controlled by the output of the allocation memory. a noise level detector that has a switch circuit that outputs M speech lines (M>N) from a line input, and receives the output of the allocation memory and the output of the speech lines and detects the average level of noise for each speech line; a level control circuit that takes in the output of the noise level detector and changes the value of the noise level; a random noise generator that generates random noise according to the output of the level control circuit; and a random noise generator that generates random noise output from the random noise generator. 1. A receiving side circuit of a DSI device, comprising a noise insertion circuit inserted into a communication line to which no communication path is assigned.