JPS59216342A - Digital sound inserting device - Google Patents

Abstract

PURPOSE:To transmit an audio signal efficiently by performing detection of the voiced state in the transmission side, assignment of audio signal transmission lines accompanied with this detection, etc. with codes based on expressions corresponding to momentarily changing instantaneous values of the audio signal. CONSTITUTION:A DSI transmission-side device 12 consists of a voice detector 4, a transmission-side line connection control circuit 5, a transmission-side matrix switch 6, and a transmission-side code converting circuit 14. A DSI reception-side device 13 consists of a reception-side line connection control circuit 8, a reception-side switch matrix 9, and a reception-side code converting circuit 15. Generally, the number of audio signal transmission lines 10a, 10b...10c connecting the DSI transmission-side device 12 and the DSI reception-side device 13 is set to a value smaller than the number of individual transmission lines 1a, 1b...1c and the number of individual reception lines 2a, 2b...2c. An assigning signal transmission line 11 connects the transmission-side line connection control circuit 5 and the reception-side line connection control circuit 8.

Description

DETAILED DESCRIPTION OF THE INVENTION When transmitting a telephone call voice signal, the present invention does not necessarily transmit the voice signal during a time period in which the voice signal does not actually exist even when the line is connected, that is, the voice signal is not in a voiced state. A digital audio insertion device (hereinafter referred to simply as D) that aims to improve the efficiency of transmission line usage by not allocating transmission lines for signal transmission.
SI device).

A conventional device of this type is shown in FIG.

In the figure, ■ is a transmitting line bundle, and la.

lb,...IC is the individual transmission line that makes up the IC.

2 is a receiving line bundle, and 2a, 2b, . . . , 2C are individual receiving lines making up the bundle. 3 is a DSI transmission side device, which includes a voice detector 4, a transmission side line connection control circuit 5. and a transmission side switch matrix 6. Reference numeral 7 denotes a DSI receiving side device, which is composed of a receiving side line connection control circuit 8 and a receiving side switch matrix 9. 10 is an audio signal transmission line bundle connecting the DSI transmitting side device 3 and the DSI receiving side device 7;
, IOb, . . . , IOC are individual audio signal transmission lines that constitute it. Here, the number of individual voice signal transmission lines ioa, 10b, ..., 10c is the number of individual transmission lines 1a, lb, ..., lc and the number of individual reception lines 2
It is generally set to a smaller value than the number of a, 2b, . . . , 2C. Reference numeral 11 designates a signal transmission line, which connects the transmitting side line connection control circuit 5 and the receiving side line connection control circuit 8.

Next, the operation will be explained.

Individual transmission lines 1a forming transmission line bundle 1.

The voice detector 4 determines whether or not the voice signals transmitted through the voice lines 1b, . . . It will be judged. As a result, 9 individual transmission lines 1a
, 1b, . And it is in a voiced state. For the individual transmission line determined to be, from among the individual voice signal transmission lines 10a, 10b, =-, 10c that constitute the voice signal transmission line bundle 10.

At that time, one of the lines that is not connected to the individual transmission line in the voiced state is selected and assigned to the individual transmission line in the voiced state. This operation is performed by the transmission side line connection control circuit 5. Further, the transmission side switch matrix 6 connects the corresponding individual lines of the transmission line bundle 1 and the voice signal transmission line bundle 10 in accordance with the result of the allocation made by the transmission side line connection control circuit 5.

For the individual audio signal transmission lines involved in this connection,
The connections that were in place at the time the above allocation was made are as follows:
It will be released when a connection corresponding to the current allocation is made. The details of the connection associated with this assignment, that is, the combination of the individual transmission line number and the corresponding individual audio signal transmission line number, are assigned by the transmission side line connection control circuit 5 via a signal. It is transmitted to the receiving side line connection control circuit 8 through the transmission line 11. Then, the receiving side line connection control circuit 8 determines corresponding individual line pairs of the voice signal transmission line bundle 10 and the receiving line bundle 2 based on the information, and generates a control signal for the receiving side switch matrix 9. do. The receiving side switch matrix 9 connects the determined individual line pairs to each other in accordance with the control signal.

By the operation described above, among the five individual transmission lines 1a, lb, . . . Individual audio signal transmission lines 10a, 1
It is clear that up to the number of lines 0b, . . . 10c can be effectively connected.

By the way, in a normal telephone conversation, while one person is the speaker, the other person is the listener, silently listening to what the other person is saying.

While listening to the other party, the individual transmission line on the side corresponding to the listener becomes silent. Since the positions of the speaker and the listener usually take turns, if we consider only one direction of a telephone transmission line in a two-way conversation, this line becomes voiced and effectively transmits voice signals. It is easy to imagine that the time rate would be less than 50%, and the validity of this assumption has been statistically confirmed. In addition to this, even if a line that has no voice signal to effectively transmit, i.e. is in a silent state, is disconnected, the connection will be restored when it is in a voiced state. Taking into consideration that there will be no problem with telephone calls, the transmitting line bundle 1. When the number of individual lines constituting each receiving line bundle 2 is large to some extent, the above-mentioned Since there is a connection between the sending line bundle 1 and the receiving line bundle 2,
When transmitting audio signals, analog transmission methods and PCM
There is no problem if it depends on a transmission method that transmits the amplitude of the signal at each instant.

When using a method such as delta modulation method or delta PCM method, which transmits the amplitude value of a signal at a certain point in time, the signal is determined based on the state of the signal before that point. There were the following problems.

That is, for an individual transmission line that is determined to be in a voiced state by the voice detector 4, any of the individual voice signal transmission lines that are not connected to the individual transmission line that is in a voiced state at that time is - is assigned, and audio signal transmission begins from that point on.At this time, the above assignment is applied to the individual receiving line corresponding to the individual transmitting line determined to be in the voiced state. There exists a silent state, that is, a state in which signals corresponding to a voice signal level of zero are continuously received until the point in time when the above allocation is made, and from the point in time onwards, the voice signal given to the corresponding individual transmission line is You will be guided as you are. Considering that before the above allocation, the audio signals given to the individual transmission lines corresponded to a silent state, as explained above,
Even with a method in which the transmitting line and the receiving line are connected via the audio signal transmission line only after the voiced state is detected on the transmitting line side, it is possible to connect the transmitting line and the corresponding line without depending on the D or SL device. The receiving line can receive the same voice signals as if the receiving line were permanently connected.

As described above, there is no problem in an ideal operating state in which the voice signal transmission line is allocated at the same time as the transmission line changes from the unvoiced state to the voiced state. However, if for some reason the voice signal transmission line is allocated after a certain period of time has passed since the voiced state has been changed, a problem will occur. Such a situation may occur, for example, in a situation where a large number of individual transmission lines change from a silent state to a voiced state within a short period of time, and the processing cannot keep up with the 1 allocation, or when individual transmission lines in a voiced state This may occur in response to a situation where the number of lines temporarily exceeds the number of individual audio signal transmission lines. If such a situation does not occur, the audio signal corresponding to the voiced state until the 9-allocation is completed is not transmitted and is lost. This means that even if it is unavoidable, even after 1 allocation has been made and audio signal transmission has actually started, the delta modulation method, delta PCM method, or predictive codes based on these methods will be used for audio signal transmission. When this method is used, a problem arises in that the overwhelming audio signal is not transmitted for a certain period of time. This is because on the sending line side, a voice signal is generated assuming the existence of a voiced state before the transmission line is allocated, while on the receiving line side, the unvoiced state continues until just before the allocation is made. This is because it is not possible to interpret the voice signal immediately after the transmission line according to the intention of the transmission line. For this reason, there is a possibility that correct audio signal transmission may not be performed for a certain period of time even after line allocation is performed.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it is necessary to detect the voiced state on the sending side and allocate the audio signal transmission line accordingly, as well as to execute the connection using the switch matrix. , such as the PCM transmission method, is implemented using a code expressed in correspondence to the momentary instantaneous value of the audio signal, and the code of the PCM method is applied to the transmitting end of the audio signal transmission line using the delta modulation method, delta PC.
A transmitting-side conversion circuit is provided to convert into a high-efficiency code based on the M method or a predictive coding method based on these methods, and on the receiving side, a delta modulation method or delta PCM method is installed at the receiving end of the audio signal transmission line. Alternatively, a receiving-side conversion circuit that inversely converts the high-efficiency code of the predictive coding system based on these systems into a code of the PCM system, etc. is provided, and subsequent processing and transmission are performed using the code of the PCM system, etc. To provide a DSr device which can highly efficiently transmit audio signals between sending and receiving calls, and can transmit correct audio signals from the stage immediately after the line side is installed. It is an object.

An embodiment of the present invention will be described below with reference to the drawings. Second
In the figure, 1 is a transmitting line bundle, 1a.

lb,..., lc are the individual transmission lines that constitute it,
Reference numeral 2 denotes a receiving line bundle, and 2a, 2b, . . . , 2c are individual receiving lines constituting it. 12 is a DSI transmitting side device, which is a voice detector 4. Transmission side line connection control circuit5.
It is composed of a transmitting side switch matrix 6 and a transmitting side code conversion circuit 14. 13 is a DSI receiving side device, which is a receiving side line connection control circuit 8. It is composed of a receiving side switch matrix 9 and a receiving side code conversion circuit 15. 10 is an audio signal transmission line bundle connecting the DSI transmitting side device 12 and the DSI receiving side device 13; 10a, 10b;
, . . . , 10c are individual audio signal transmission lines constituting it. Here, the number of individual audio signal transmission lines is individual transmission lines 1a, lb, . . . .

Number of ICs and individual reception lines 2a, 2b, . . .

It is generally set to a smaller value than the number 2c.

Reference numeral 11 designates a signal transmission line, which connects the transmitting side line connection control circuit 5 and the receiving side line connection control circuit 8.

Next, the operation of this embodiment will be explained.

Individual lines 1a and lb forming the transmitting line bundle 1.

..., the transmitted audio signal transmitted through the lc is
The voice detector 4 determines whether it corresponds to a voiced state or a voiceless state to the individual transmission lines 1a, lb.
, . . . are determined for each of the ICs. This result 9
It is possible to know the line status of each of the individual transmission lines 1a, lb, .

Then, it changed from a voiceless state to a voiced state. Regarding the individual transmission lines determined to be, the individual voice signal transmission lines 10a, 10b, . . . forming the voice signal transmission line bundle 10 are
・From within 10c, at that point.

The integrated control circuit 5 controls the individual audio signal transmission lines that have not been assigned to one of the individual transmission lines that are already in the voiced state.
It is carried out by Based on this assignment. Transmission line bundle 1
The connection operation performed on the individual line pairs resulting from each of the and voice signal transmission line bundles 10 is performed by the transmitting side switch matrix 6 under the control of the transmitting side line connection control circuit 5. The voice signals transmitted through some of the individual transmission lines constituting the transmission line bundle 1 as described above are guided to the output terminal of the transmission side switch matrix 6.

The output of the transmitting side switch matrix 6 is converted into a delta modulation system by a transmitting side code conversion circuit 14.
It is converted into a high-efficiency code expressed by the CM method or a predictive coding method based on these methods, and becomes the output of the DSI transmitter 12.

DSI receiving side device 13 through audio signal transmission line bundle 10
guided by. On the other hand, the allocation performed by the transmission side line connection control circuit 5 is determined as a result of the operation.The combination of each individual line of the sending line bundle 1 and the voice signal transmission line bundle 1° is 1 allocation for signal transmission. Via line 11 it is also routed to the DSI receiving device I3.

Then, the following operation is performed in the DSI receiving side device 13. That is, the reception was received through the audio signal transmission line bundle 10. The code of the audio signal expressed by the delta modulation method, the delta PCM method, or the predictive coding method based on these methods is converted into a PCM method existing representation corresponding to the value of each instantaneous value of the audio signal by the receiving side code conversion circuit 15. and then leads to the input terminal of the receiving side switch matrix 9.

The voice signal, which has been converted into a code expressed in accordance with the instantaneous value of the voice as described above, is guided by the receiving side switch matrix 9 to the corresponding individual receiving line. Here, the correspondence between the individual audio signal transmission lines and the individual receiving lines is that of the individual lines of the transmission line bundle 1 and the voice signal transmission line bundle 10 provided from the DSI transmitting side device 12 through the assigned signal transmission line 11. It is determined by the receiving side line connection control circuit 8 based on the combination. A control signal based on this determination is provided from the receiving side line connection control circuit 8 to the receiving side switch matrix 9, and the receiving side switch matrix 9 is based on the above determination. Audio signal line bundle 10
The circuit is configured to guide the output of the receiving side code conversion circuit 15 corresponding to a specific one among the individual transmission lines constituting the receiving line bundle 2 to a specific line among the individual receiving lines constituting the receiving line bundle 2. do.

In this way, as in the past, among the individual transmission lines 1a, lb, . . . It is possible to guide the voice signals applied to the number of lines up to the number of the individual voice signal transmission lines to be guided to the respective corresponding individual receiving lines. Therefore, by appropriately setting the relationship between the number of individual lines making up the sending line bundle 1 and the receiving line bundle 2 and the number of individual audio signal transmission lines making up the audio signal transmission line bundle 10.

The statistical property of the voice signal in a telephone call is that when only one direction is considered, the time rate in which it is voiced is less than 50%, and the transmission line can be used effectively. , the transmission of voice signals for telephone calls can be accomplished economically with fewer individual voice signal transmission lines than would be possible without a DSI device.

Further, in the DSI device of the above embodiment, the audio signal is transmitted between the transmitting and receiving devices using a high-efficiency code represented by a delta modulation method, a delta PCM method, or a predictive coding method based on these methods. I did it like this,
The transmission efficiency can be greatly improved, and since the transmission other than the transmission between the above-mentioned transmitting and receiving devices is transmitted and processed using the code expressed by the PCM method that transmits the amplitude of the signal at each instant, Correct audio signal transmission can be performed immediately after line allocation is performed.

Although it is assumed that the system is composed of a collection of spatially separated individual lines, some or all of these may be multiplexed lines using a frequency division method or a time division method. Furthermore, in the case of 2-allocation, the signal transmission line 11 does not need to be provided independently from the audio signal transmission line bundle 10, and may be multiplexed together with the audio signal transmission line bundle 10 configured in a multiplexing system. A specific one of the individual transmission lines that are the constituent elements of the audio signal transmission line bundle 10 configured in a multiplexed manner may be assigned to this. Furthermore, although the expression of the voice signal transmitted through the transmitting/receiving line bundle is based on the PCM method, it is not necessary to limit the expression to the PCM method as long as it corresponds to the momentary instantaneous value of the voice signal. .

As described above, according to the present invention, an audio signal transmitted through an audio signal transmission line bundle is encoded using a delta modulation method, a delta PCM method, or a predictive coding method based on these methods, and The transmitting/receiving switch matrix section, which performs switching to intermittently configure and release the line as the line changes between voiced and unvoiced states, uses voice signals such as PCM system. Transmission and processing are performed using codes that represent the instantaneous value of the audio signal, so it is possible to use the delta modulation method, delta PCM method, or any of these methods, which has higher coding efficiency than the representation of the PCM method that corresponds to the instantaneous value of the audio signal. The transmission of audio signals through the audio signal transmission line by the expression of the predictive coding method based on the system is adversely affected by the interruption of the line due to the change in the state between the voiced state and the unvoiced state of the transmission line. The effect is that it can be executed without any trouble.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a conventional digital voice insertion device, and FIG. 2 is a block diagram showing the configuration of an embodiment of the digital voice insertion device according to the present invention. 14... Transmitting side code conversion circuit, 15... Receiving side code conversion circuit. In addition, in FIG. 9, the same reference numerals indicate the same or corresponding parts. Agent Masuo Oiwa

Claims (1)

[Claims] +l) When transmitting a telephone call audio signal, even during the period when a connection is being made for a call, transmission lines are not necessarily allocated to the call during times when the audio signal is not in a voiced state. In a digital voice insertion device that improves the utilization efficiency of a transmission line by A code conversion circuit on the transmitting side converts the transmitted high-efficiency code into a high-efficiency code represented by a predictive coding method based on the method, and a code conversion circuit on the receiving side converts the transmitted high-efficiency code into a code represented by the above-mentioned instantaneous value. A digital audio insertion device comprising: a receiving side code conversion circuit that performs conversion.