JPH0263232A - Receiver side circuit for dsi equipment - Google Patents

Abstract

PURPOSE:To obtain non communication noise nearly equal to a noise included in a sender side communication line and to attain the effective utilization of a relay line by detecting an average level of a data in existing in a hung-over time of a line received at the reception side as a mean noise level. CONSTITUTION:A noise level detector 204 always references assigned control information, finds out a communication line whose connection to a relay line is about to be interrupted by the assigned control information and gives a mean value of signal levels detected just before the interruption of the communication line to a random noise generator 205. The random noise generator 205 generates a random noise given to the communication line according to the mean value of the given signal level. When the mean value of the signal levels detected just before the interruption of the communication line in this case is that detected within the hung over time of a voice detector employed for the sender side of the DSI equipment, the mean level is nearly equivalent to the mean level of the noise included in the communication line inputted to the sender side. Thus, the relay line is utilized effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a receiving side circuit of a DSI (Digital Speech Interpolation) device used to improve the utilization efficiency of a PCM telephone line.

[Prior Art] In a line used for telephone calls, the ratio of the time during which voice energy exists to the time the line is occupied is generally 40% or less, and only the section where this voice energy exists is effective. By transmitting the information to the relay line, the information can be transmitted using the number N of relay lines (N is an integer greater than or equal to 1), which is smaller than the number M of connected communication lines, and the efficiency of use 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 a DSI device detects a section in a speech line where voice energy exists, connects the speech line and a relay line, and transfers this connection information (hereinafter referred to as communication path allocation information) to the relay line. via a dedicated time slot,
Communication path data is sent to the assigned relay line.

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, there are fewer relay lines than voice lines, so
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, very low-level (not harsh) random noise is generally inserted.

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

First, referring to FIG. 2 (A), on the transmitting side, M (the number of telephone lines) is connected to the transmitting side input terminal from the transmitting side telephone line.
A line PCM signal is input.

This input signal passes through the delay circuit 10 and is input to the transmission side high speed switch circuit 20. Further, the PCM signal inputted to the transmitting side input terminal 1 is input to a voice detector 30 that detects the presence of voice energy.

One output of this voice detector 30 is input to a transmission side assignment control circuit 40. Further, the other output of the voice detector 30 is input to the noise level detector 50 . The transmission side allocation control circuit 40 allocates the communication path according to the output of the voice detector 30, and transmits the communication path allocation information to the transmission side high speed switch circuit 2o.
and is sent to the allocation information encoder 60. Noise level detector 5
0 detects the average value of the noise level for each line during the time when there is no voice energy on the input speech line and inputs it to the allocation information encoder 60. The assignment information encoder 60 is assigned to channel assignment information and channel assignment information. The noise level of the telephone line is encoded, and an allocation information code is created and output. The transmission side high-speed switch circuit 20, according to the call path assignment information,
PCM signals of N lines corresponding to the number of relay lines N (N<M) are output, and these PCM signals of N lines are sent to the allocation information encoder 6.
It is sent from output terminal 2 to the trunk line together with the allocation information code output from 0.

On the other hand, 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 3 from the relay line. Among these, the PCM signal of N lines is input to the receiving side high-speed switch circuit 90, and at the same time, the assignment information code is input to the assignment information decoder 70, and the call route assignment information and the call assigned to the call route assignment information are input. decoded to the average noise level of the line. The receiving side allocation control memory 80 is controlled by this combined communication path allocation information, and the receiving side allocation control memory 80 manually inputs the allocation control information to the receiving side high speed switch circuit 90 and the noise insertion circuit 110.

The output of the receiving side high speed switch circuit 90 is given to the noise insertion circuit 110 as an M line PCM signal. In addition, the average noise [Novel] decoded by the allocation information decoder 70 is input to the random noise generator 100, and the random noise generator 100 generates random noise according to this average noise level for each communication path, The signal is input to the noise insertion circuit 110. The noise insertion circuit 110 checks the allocation control information and
Random noise is inserted into speech lines to which no trunk lines are assigned. The output of this noise insertion circuit 110 is
The signal is sent from the receiving side output terminal 4 to the receiving side communication line as a PCM signal of the M line.

[Problems to be Solved by the Invention] As described above, according to the conventional technology, a method is adopted in which 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. Therefore, there was a drawback that the relay line could not be used effectively.

An object of the present invention is to eliminate such drawbacks of the conventional system, eliminate the need for sending information regarding noise during no calls from the transmitting side to the receiving side, and thus enable effective use of trunk lines. It provides a receiving side circuit of a DSI device.

[Means for Solving the Problems] According to the present invention, the DS
The receiving circuit of the DSI device which is designed not to send information regarding noise during no call to the receiving circuit of the I device, and the number of received circuits N (N is an integer of 1 or more)
means for separating call path assignment information from the relay line inputs of and decoupling the call path allocation information; an allocation memory for storing the decombined call path allocation information; and a relay line input of N lines controlled by the output of the allocation memory. to M (M is an integer greater than N) based on the switch circuit that outputs the speech line of the line, the output of the allocated memory and the output of the speech line, calculate the average level of data existing within the hangover time of the speech line. a noise level detector that detects the average of the noise; and changing the output level of the random noise based on the output of the noise level detector to generate random noise that is substantially equal to the noise included in the transmitting circuit. A receiving side circuit of a DSI device is obtained, which includes a random noise generator and a noise insertion circuit that inserts random noise output from the random noise generator into a communication line to which no communication path is assigned. .

[Example] Next, the present invention will be explained with reference to the drawings.

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

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 300 from the relay line. Among these, the PCM signals of N lines are input to the receiving side high-speed switch circuit 201, and at the same time, the allocation information code in the relay line is manually input to the allocation information decoder 202 and decoded into channel allocation information. The receiving side allocation control memory 203 is controlled by this combined communication channel allocation information, and the receiving side allocation control memory 203 sends the allocation control information to the receiving side high speed switch circuit 201 and the noise level detector 204. The output of the receiving side high-speed switch circuit 201 is P of the M line.
The signal is given to the noise insertion circuit 206 and the noise level detector 204 as a CM signal.

The output of the noise level detector 204 is the random noise generator 2
05, and the output of the random noise generator is input to the noise insertion circuit 206, and the noise insertion circuit 206, while referring to the output of the receiving side assignment control memory 203, performs an input to a call line to which no call assignment has been made. Insert random noise. The output of this noise insertion circuit 206 is
The M signal is sent from the receiving side output terminal 301 to the receiving side speech line.

The above is the configuration of the embodiment according to the present invention, and the present invention is characterized by the noise level detector 204. The characteristics will be explained below.

Typically, a voice detector on the transmitting side of a DSI device detects voice energy by integrating the signal level of the incoming speech line; If the voice detector determines that there is no voice energy due to the level part, unnecessary voice disconnections will occur frequently and the clarity of the call will deteriorate, so a hangover period is provided to give the voice detector inertia. ing.

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 204 used in the present invention receives and receives the M-line speech line output from the receiving side high-speed switch circuit 201 and the allocation control information output from the receiving side allocation control memory 203, and keeps the PCM signal of the speech line constant. The average value of the signal level of each line is detected by dividing the line by time, and the average value of the signal level of each line is held. On the other hand, the noise level detector always refers to the allocation control information, uses the allocation control information to find a call line that is about to be disconnected from the trunk line, and detects the signal detected just before the call line is disconnected. Random noise generator 2
05.

Random noise generator 205 generates random noise to be applied to the speech line according to the average value of the applied signal level.

Here, if the average value of the signal level detected immediately before the call line is disconnected is at least within the hangover time of the voice detector used on the transmitting side of the DSI device, it is input to the transmitting side. This is approximately equivalent to the average level of noise contained in the telephone line.

[Effects of the Invention] As described above, according to the present invention, information regarding noise during no calls is not sent from the transmitting side of the DSI device to the receiving side, and only on the receiving side of the DSI device, the received line By detecting the average level of data present within the hangover time as the average level of noise, it is possible to obtain a no-call noise that is approximately equal to the noise included in the transmitting call line, and to detect the effective level of the trunk line. This has the effect of making it possible to achieve various uses.

[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 of an example of a conventional DSI device. In FIG. 1, 201: high-speed switch circuit on the receiving side, 202: allocation information decoder, 203: allocation control memory on the receiving side, 204: noise level detector, 205 two random noise generators, 206: noise insertion circuit, 300: Receiving side input terminal, 301: Receiving side output terminal, In Fig. 2, 1: Sending side input terminal, 2: Sending side output terminal, 3: Receiving side input terminal, 4: Receiving side output terminal, 10 :Delay circuit, 20
: Transmission side high-speed switch circuit, 30: Audio detector, 40:
Transmission side allocation control memory, 50: Noise level detector, 60
: Allocation information encoder, 70: Allocation information decoder, 80: Receiving side allocation control memory, 90: Receiving side high speed switch circuit, 1
00: Random noise generator, 110: Noise insertion circuit. Figure 1

Claims (1)

[Claims] 1. The receiving circuit in the DSI device, which prevents information regarding noise during no calls from being sent from the transmitting circuit of the DSI device to the receiving circuit of the DSI device,
means for separating call path assignment information from the received trunk line inputs of the number of lines N (N is an integer of 1 or more) and decoding the call path assignment information; an allocation memory for storing the decombined call path assignment information; A switch circuit that is controlled by the output of the allocation memory and outputs M (M is an integer greater than N) communication lines from the relay line input of N lines; a noise level detector that detects the average level of data existing within the hangover time of the line as an average noise; and a noise level detector that changes the output level of random noise based on the output of the noise level detector, and a random noise generator that generates random noise that is substantially equal to the noise that is being received; and a noise insertion circuit that inserts the random noise output from the random noise generator into a communication line to which no communication path is assigned. A receiving side circuit of a DSI device characterized by: