JPH06315050A - Telephone equipment for conference - Google Patents

Abstract

PURPOSE:To reduce cost by canceling sidetone caused by plural voice signals by using one echo canceler. CONSTITUTION:The voice signal of a microphone 48 at a telephone set 21 is supplied from an adder 54 and two-wire/four-wire conversion circuits 22-1-22-n to respective telephone sets. The voice signal of any one telephone set is supplied from the conversion circuit 22-1, for example, adder 34 and echo canceler 36 to the telephone set 21. The output signal of the canceler 36 (the signal of the conversion circuit 22-1) is also supplied from an adder 54 to the conversion circuits 22-1-22-n and sent to each telephone set. At such a time, the sum of the voice signal of the telephone set 21 and the voice signal of the conversion circuit 22-1 is supplied from the conversion circuits 22-1-22-n to the adder 34 as the sidetone and supplied to the canceler 36. Since the output signal of the adder 54 (the voice signal of the telephone set 21 and the voice signal of the conversion circuit 22-1) is supplied to the canceler 36 as a control signal, this sidetone is canceled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone device for conference use, and more particularly, it can send voice signals to a plurality of telephone lines at the same time, and the above-mentioned method can be used even when the voice signals are sent simultaneously. The present invention relates to a device capable of receiving a voice signal from each telephone line.

[0002]

2. Description of the Related Art Conventionally, there is a conference telephone device as shown in FIG. 3, for example. In this conference telephone device, the voice signal from the microphone 2 is supplied from the conference bridge 4 to the 2-line-4 line conversion circuits 6-1 to 6-n, from which the telephone lines 8-1 to 8-n and the exchanges are exchanged. 10
Is supplied to each of the telephones 12-1 to 12-n via the.
Therefore, voice signals can be sent to all the telephones 12-1 to 12-n all at once.

At this time, crosstalk to the conference bridge 4 side generated in each of the 2-wire to 4-wire conversion circuits 6-1 to 6-n is supplied from the conference bridge 4 to the speaker 14 to cause howling. 2 lines each to prevent
Echo cancellers 16-1 to 16-n are provided between the four-line conversion circuits 6-1 to 6-n and the conference bridge 4, respectively. The echo cancellers 16-1 to 16-n are controlled by using the audio signals supplied from the conference bridge 4 to the 2-line to 4-line conversion circuits 6-1 to 6-n.

Further, as described above, the telephones 12-1 to 12-1
In the state where the voice signals are simultaneously sent to 2-n, the voice signals from any of the telephones, for example, telephone 12-1, are transmitted to the exchange 10, telephone lines 8-1, 2-4.
It is supplied to the speaker 14 via the line conversion circuit 6-1, the echo canceller 16-1, and the conference bridge 4. Therefore, even when the voice signals are simultaneously transmitted to the respective telephones 12-1 to 12-n, the respective telephones 12-
Audio signals from 1 to 12-n can be received.

[0005]

In the conference telephone device as described above, it is possible to simultaneously send the voice signals to the respective telephones 12-1 to 12-n, and in this transmitting state, the respective telephones 12-1 to 12-12. It is also possible to receive the voice signal from -n, but for each telephone line 8-1 to 8-n,
Since expensive echo cancellers 16-1 to 16-n have to be provided, there is a problem that the cost becomes high.

According to the present invention, it is possible to transmit voice signals to a plurality of telephone lines all at once, and to receive voice signals from each telephone line even in the state where they are simultaneously transmitted. It is also intended to reduce the number of echo cancellers to be used and to reduce the cost.

[0007]

The audio signal having first to third terminals and supplied to the first terminal is output mainly to the second terminal, and the audio signal supplied to the third terminal is output. A plurality of directional coupling means, which are mainly configured to output to the first terminal and each of which is connected to a telephone line, and an audio signal output from each second terminal of these directional coupling means First adding means for adding, and canceling means for canceling a leak signal from the third terminal to the second terminal of each of the directional coupling means included in the output signal of the adding means according to the control signal. An output terminal to which the output signal of the cancel means is supplied, an input terminal to which the audio signal is supplied, the output signal of the cancel means and the audio signal from the input terminal are added, and the added output is the control signal. And a second adder means for supplying with the third terminal of each directional coupling means is supplied to said canceling means, is intended to comprise.

[0008]

According to the present invention, the audio signal supplied to the input terminal is supplied from the second adding means to the second terminal of each directional coupling means. The audio signal supplied to the second terminal of each directional coupling means is supplied to the first terminal, and from these, is supplied to each telephone line. That is, it is possible to simultaneously transmit audio signals to each telephone line.

In this state, when audio signals are supplied from the respective telephone lines to the first terminals of the respective directional coupling means, these audio signals are generated at the second terminals of the respective directional coupling means, These are added by the first adding means and supplied to the input terminal via the echo canceller. Therefore, even when audio signals are simultaneously transmitted to each telephone line, the audio signal from each telephone line can be received.

At this time, since the signal obtained by adding the output signal of the echo canceller and the audio signal of the input terminal by the second adding means is supplied to the echo canceller as a control signal, the signal is supplied from the echo canceller to the output terminal. When an audio signal from each telephone line side wraps around to the input terminal and is supplied from the second adding means to the third terminal of each directional coupling means, it occurs as crosstalk on the second terminal side, Even if these crosstalks are added by the first adding means and supplied to the echo canceller, they are canceled by the control signal, so howling does not occur.

[0011]

EXAMPLE A first example is shown in FIG. In this embodiment, a conference telephone device 20 according to the present invention is provided. The conference telephone device 20 is used to make a call between a plurality of telephones in the hands of participants in a plurality of conferences and a telephone 21 in the hands of the participants in the conference via a plurality of telephone lines. belongs to.

The conference telephone device 20 has directional coupling means, for example, 2-line to 4-line conversion circuits 22-1 to 22-n, which are respectively connected to the telephone lines (not shown). These 2-wire to 4-wire conversion circuits 22-1 to 22-n
Have terminals 24-1 to 24-n, 26-1 to 26-n and 28-1 to 28-n, respectively.

Although each of these terminals is shown as one terminal in FIG. 1, each of them is actually composed of two terminals connected to two wires. In the 2-line to 4-line conversion circuit 22-1, the audio signal supplied to the terminal 24-1 via, for example, a telephone line is mainly output to the terminal 26-1. The audio signal supplied to the terminal 28-1 is mainly output to the terminal 24-1. However, a part of the audio signal supplied to the terminal 28-1 occurs at the terminal 26-1.
That is, sidetone is generated. Sidetone is similarly generated in the other 2-line to 4-line conversion circuits 22-2 to 22-n.

2-line to 4-line conversion circuits 22-1 to 22-n
The audio signals supplied to the terminals 24-1 to 24-n of the A / D converters 30-1 to 30- are output to the terminals 26-1 to 26-n. n, and converted into a digital signal. These digital signals are attenuated by the attenuators 32-1 to 32-n and then supplied to the adder 34. The attenuation amount of each of the attenuators 32-1 to 32-n can be arbitrarily adjusted.

The digital signals supplied to the adder 34 are added by the adder 34 and supplied to the echo canceller 36. The output signal of the echo canceller 36 is supplied to the output terminal 40, then supplied to the D / A converter 42 in the telephone 21, converted into an analog signal, amplified by the amplifier 44, and then supplied to the speaker 46. .

The telephone 21 is also provided with a microphone 48, and the audio signal picked up by the microphone 48 is A /
It is converted into a digital signal by the D converter 50 and supplied to the input terminal 52 of the conference telephone device 20. The digital signal of the input terminal 52 and the output signal of the echo canceller 36 are supplied to the adder 54. This adder 5
The added output of 4 is supplied as a control signal to the echo canceller 36, and further converted into an analog signal by the D / A converter 56, and each 2-wire to 4-wire conversion circuit 22.
-1 to 22-n terminals 28-1 to 28-n.

The conference telephone device 20 configured as described above.
Then, for example, the voice signal A picked up by the microphone 48 of the telephone 21 is converted into the digital signal A1 by the A / D converter 50, and is converted into the D / A converter 56 via the input terminal 52 and the adder 54. It is supplied and converted again into the analog audio signal A, and each of the 2-wire to 4-wire conversion circuits 22-1 to 22 is supplied.
-N terminals 28-1 to 28-n. The analog audio signal A is converted into a 2-line to 4-line conversion circuit 22-1.
22 to 22-n of terminals 24-1 to 24-n and are supplied to each telephone through a telephone line connected to these terminals. That is, the voice signal A from the telephone 21 is sent to all the telephones simultaneously via the telephone line.

At this time, each 2-wire to 4-wire conversion circuit 22-1
To terminals 22-1 to 26-n and terminals 28 to
-1 to 28-n, a part of the analog voice signal is generated as sidetone AS, converted into a digital signal AS1 by each A / D converter 30-1 to 30-n, and attenuator 32-1. Through 32-n, and is supplied to the echo canceller 36 via the adder 34. Echo canceller 3
6, the digital voice signal A1 is supplied as a control signal via the adder 54, so that the side tone voice signal A1 is supplied.
S1 is canceled by the echo canceller 36 and is not supplied to the speaker 46. Therefore, howling does not occur.

In the state where the voice signal from the microphone 48 is being sent to each telephone through the telephone line in this way,
Via the telephone line, for example, a 2-line to 4-line conversion circuit 22-1
When the audio signals B and C are supplied to the terminals 24-1 and 24-n of the 22-n and 22-n, respectively, the audio signals B and C are supplied to the terminals 26 of the 2-wire to 4-wire conversion circuits 22-1 and 22-n. -1 and 26-n, and A / D converters 30-1 and 30-n
Is converted into digital signals B1 and C1 and is supplied to the adder 34 via the attenuators 32-1 and 32-n,
After being added here, it is supplied to the D / A converter 42 via the echo canceller 36 and the output terminal 40. Here, it is converted into analog audio signals B and C again, amplified by the amplifier 44, and supplied to the speaker 46. Therefore,
The above two voice signals B and C are received by the telephone 21.

The digital signals B1 and C1 generated at the output side of the echo canceller 36 are output from the adder 54 to D.
To the A / A converter 56, where the audio signals B, C again
2 to 4 line conversion circuits 22-1 to 22-
n terminals 28-1 to 28-n. Terminal 28
-1 to 28-n, the audio signal supplied to the terminal 24-
1 to 24-n and is supplied to each telephone through each telephone line. Therefore, the two voice signals supplied via the telephone line are supplied to the other telephone through the conference telephone device 20 and the telephone line.

A voice signal B is applied to terminals 28-1 to 28-n,
By supplying C, sidetones BS and CS are generated at the terminals 26-1 to 26-n. These side sounds BS and CS are A
Digital signal BS by the D / D converters 30-1 to 30-n
1, is converted to CS1, supplied to the adder 34 via the attenuators 32-1 to 32-n, added here, and then supplied to the echo canceller 36. At this time, since the echo canceller 36 is supplied with the digital signals B1 and C1 from the adder 54, the side tone digital signals BS1 and CS1 are canceled. Therefore, the side sounds BS and CS are not supplied to the speaker 46, and howling does not occur.

Since the attenuators 32-1 to 32-n are provided, the telephone line to 2-line to 4-line conversion circuit 22-1 is provided.
22 to 22-n, the digital signals B1 and C1 of the audio signals B and C are attenuated and then supplied to the adder 54 via the adder 34, where the audio signal A of the microphone 48 is transmitted.
Is added to the digital signal A1. Therefore, the levels of the digital signals B1 and C1 are lower than the level of the digital signal A1. The digital signals B1 and C1 whose levels have been reduced are converted into analog signals by the D / A converter 56 together with the digital signal A1 whose level has not been adjusted, and then the 2-wire to 4-wire conversion circuits 22-1 to 22-n. Since the data is supplied to each telephone through the telephone line, each telephone can clearly distinguish the voice signal from the telephone 21 and the voice signal from another telephone due to the difference in level.

Further, since the attenuators 32-1 to 32-n are provided for each telephone line, the attenuation amount can be changed for each telephone line, and the attenuation amount can be changed corresponding to the reached level for each telephone line. By changing the, the volume reached to each telephone line can be adjusted to be constant. However, telephone 2
In No. 1, since the voice signal once attenuated is amplified by the amplifier 44, the voice signal from each telephone line can be returned to the original amplitude level and can be heard.

The second embodiment is shown in FIG. In this embodiment, conference telephone devices 20-1 to 20-m having the same configuration as the conference telephone device 20 shown in FIG. 1 are provided, and n conference telephone devices 20-1 to 20-m are provided. The telephones are connected to each other via the telephone line.

The output terminals 40-1 to 40-m of the conference telephone devices 20-1 to 20-n are connected to a conference bridge 58 similar to the conference bridge 4 shown in FIG.
The output signal generated at the output terminal 60 of the conference bridge 58 is converted into an analog voice signal by the D / A converter 42 of the telephone 21, and is supplied to the speaker 46 via the amplifier 44.

A digital signal obtained by digitally converting the voice signal from the microphone 48 of the telephone 21 by the A / D converter 50 is input from the conference bridge 58 to the input terminals 52- of the conference telephone devices 20-1 to 20-m. 1 to 52-
is being supplied to m.

In this embodiment, the microphone 48 of the telephone 21 is
The audio signal picked up by is digitized by the A / D converter 50, and is input via the conference bridge 58 to the input terminals 52-1 to 52 of the conference telephone devices 20-1 to 20-m.
Is supplied to the telephone lines 1-1 to m-n via the conference telephone devices 20-1 to 20-m at the same time as in the first embodiment. At this time, the echo canceller in each of the conference telephone devices 20-1 to 20-m cancels the sidetone of the voice signal of the microphone 48 as in the first embodiment, and howling does not occur.

In the state in which the data are simultaneously sent out in this way,
When a voice signal is supplied from any one of the telephone lines 1-1 to mn, for example, from the telephone line 1-1, this is supplied from the conference telephone device 20-1 to the conference bridge 58 and then to the telephone 21. As well as being supplied to the conference telephone devices 20-1 to 20-m, each telephone line 1
-1 to m-n. Therefore, telephone line 1-1
The voice signal from the telephone is also supplied to another telephone line. In addition,
Input terminal 52 of each conference telephone device 20-1 to 20-n
The fact that the voice signal input to -1 to 52-m occurs as sidetone at the output terminals 40-1 to 40-m is canceled by the echo canceller in each of the conference telephone devices 20-1 to 20-m. .

In the above embodiment, the conference telephone device 20,
Although an attenuator is provided in each of 20-1 to 20-m, it may be removed in some cases. Also, each attenuator is A
Although provided between the D / D converters 30-1 to 30-n and the adder 34, the 2-wire to 4-wire conversion circuits 22-1 to 22-n are provided.
And each of the A / D converters 30-1 to 30-n may be provided, or only one may be provided between the adder 34 and the echo canceller 36. Further, in each of the above embodiments,
Although the attenuators 32-1 to 32-m, the adder 34, the echo canceller 36, and the adder 54 in the conference telephone device are configured by digital circuits, they may be configured by analog circuits. Further, each of the above digital circuits can be configured by software using a DSP (digital signal processing device) or the like.

[0030]

As described above, in the conference telephone device according to the present invention, the voice signal from the input terminal can be simultaneously transmitted to each telephone line, and the transmission from a certain telephone line can be transmitted to other telephone lines. In addition to being able to send to the telephone line, even if the side tone based on the voice signal from any telephone line is provided with only one canceling means, it can be prevented from occurring at the output terminal, The cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a first embodiment in which a conference telephone device according to the present invention is implemented.

FIG. 2 is a block diagram of a second embodiment in which the conference telephone device is implemented.

FIG. 3 is a block diagram of a conventional conference telephone device.

[Explanation of symbols]

20 conference telephone device 22-1 to 22-n 2-line to 4-line conversion circuit (directional coupling means) 24-1 to 24-n first terminal 26-1 to 26-n second terminal 28-1 To 28-n third terminal 34 adder (first adding means) 36 echo canceller (canceling means) 40 output terminal 52 input terminal 54 adder (second adding means)

Claims (1)

[Claims] 1. An audio signal having first to third terminals and supplied to a first terminal is mainly output to a second terminal, and an audio signal supplied to a third terminal is mainly a first signal. A plurality of directional coupling means each having a first terminal connected to a telephone line and an audio signal output from each second terminal of these directional coupling means. And a canceling means for canceling the leak signal from the third terminal to the second terminal of each of the directional coupling means included in the output signal of the adding means according to the control signal, and the canceling means of the canceling means. An output terminal to which an output signal is supplied, an input terminal to which an audio signal is supplied, an output signal of the canceling means and an audio signal from the input terminal are added, and the added output is used as the control signal. A conference telephone device comprising: a cell means and a second addition means for supplying the third terminal of each of the directional coupling means.