JP2638280B2 - Distance lecture system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is used for a remote lecture system of an education system using a communication satellite. In particular, it relates to an audio signal of a remote lecture system.

〔Overview〕

According to the present invention, in a remote lecture system, an echo canceller is provided on the reception side of each classroom, and the voice signal generated by the questioner himself who returns after being added to the voice signal of the instructor on one radio wave is eliminated. It is very easy to do.

[Conventional technology]

FIG. 3 is a block diagram of a conventional remote lecture system.

A remote lecture system can be considered as one utilization technology of communication satellites. Satellite communication is broadcast, and it is possible to install many receiving stations for one transmitting station, and it is possible to distribute the same information to many points, which is used as a remote lecture. Is done. The lecturer who gives a lecture sends a signal from one place, and the student attends the lecture by the receiver.

In such a remote lecture, an image signal, an audio signal, and a data signal are used. Here, only the audio signal will be described.

In the distance lecture system, not only the lecturer unilaterally lectures, but also it is necessary to receive questions from the students, and the contents of the education are obtained by listening to the exchange between the lecturer and the questioner by other students. Can be confirmed and deepened.

For this reason, in the remote lecture system, the same two-way communication is required by connecting the lecturer's studio and the classroom of the inquirer with a communication line. This is a case where there is a one-to-one correspondence between the instructor's studio and the classroom. This is impossible simply by connecting the teacher's studio to the classroom. The use of satellites enables one-to-N communication.

Conventionally, a remote lecture system using a satellite has a configuration shown in FIG. That is, emitted to the communication satellite 11 via radio waves f ₁ the lecturer of the audio signal from the lecturer studio 1B in transmitters ₇₁ in the case of receiving a lecture from lecturer studio 1B, communications satellite
11 through listening to audio signals received by the receiver ₈₂ in each classroom 2B. In this case, the configuration is the same as that of education in TV broadcasting or radio broadcasting using terrestrial signals. When there is a question of a single classroom 2B audio signal of the classroom 2B is issued to the communication satellite 11 from the transmitter 7 _2, the audio signal of the questioner via the communication satellite 11 by lecturer studio 1B receiver 8 _1, Receive.

In this state, in the other classroom 2B, the instructor's studio 1B
Unless a receiver for receiving radio waves from the user and a receiver for receiving radio waves from the classroom in which the questioner is provided are provided, the exchange of questions cannot be received. The radio waves used for communication satellites are limited, and effective use is measured, so one remote lecture system uses a maximum of two radio waves. One radio wave is allocated to the radio wave from the studio and the other radio wave is allocated to the radio wave from the questioner. In this case, only one classroom can ask questions, and it is not possible to ask questions from two places at the same time.

There is a case where only one radio wave is used in consideration of effective use of the radio wave. In this case, the voice signal from the interrogator uses a terrestrial line, that is, a telephone line. In this case, it is necessary to extend a line between the lecturer's studio and each classroom with a dedicated line or the like, which is economically problematic.

In either configuration, as shown in FIG. 3, in order to transmit both the instructor and the interrogator's audio signals to the classroom other than the interrogator, the instructor's studio 1B uses the instructor's studio 1B and the instructor's audio and the sum of the audio signal, it is conceivable to transmit as a radio wave f _1. By doing so, it is possible to listen to the audio signals of both the instructor and the inquirer simply by installing one receiver in each classroom.

[Problems to be solved by the invention]

However, in such a conventional remote lecture system, even in a classroom where a questioner is present, the instructor's voice and the questioner's own voice signal are also heard. Communication satellites have a delay of about 500 msec, and have the drawback that it is very difficult for a questioner to speak.

The present invention solves the above-mentioned drawbacks, and it is possible to delete a voice signal generated by a questioner himself who is added to a voice signal of a lecturer in one radio wave and returned, thereby enabling a conversation to be performed very easily. The purpose is to provide a lecture system.

[Means for solving the problem]

The present invention includes a plurality of classrooms, and an instructor-side studio in which an instructor remotely lectures a student in the plurality of classrooms,
The instructor-side studio includes an instructor-side microphone that outputs the instructor's audio signal, input means that inputs the audio signal from each of the classrooms, and an output signal of the instructor-side microphone and an output signal of the input means. A first adder circuit, an instructor-side transmitting means for transmitting an output signal of the first adder circuit to each of the classrooms via a communication satellite by one radio wave, and an output signal of the input means as sound. A classroom-side receiving means for receiving an output signal of the lecturer-side transmitting means via the communication satellite by the one radio wave, and an audio signal of the classroom-side receiving means. A classroom-side speaker that outputs the classroom-side microphone, a classroom-side microphone that outputs the student's voice signal, and an output unit that outputs the classroom-side microphone's output signal to the instructor-side studio. In each of the classrooms, the output signal of the classroom-side microphone is branched, and one of the branched signals is transmitted from the output unit to the input unit, the first addition circuit, and the instructor side. A delay circuit for providing a delay corresponding to the time required to return to the classroom-side receiving means via the transmitting means to the other branched signal, and inserted between the classroom-side receiving means and the classroom-side speaker The echo signal is added to the instructor's voice signal based on the output signal of the delay circuit and added to the instructor's voice signal, and echo cancellation is performed to delete the voice signal generated by the learner himself.

Further, in the present invention, each of the output units includes a classroom-side transmitting unit that transmits an output signal of the classroom-side microphone to the instructor-side studio via the communication satellite by another one radio wave, and the input unit includes: The instructor-side receiving means may receive an output signal of each of the output means via the communication satellite by the other one radio wave and provide the output signal to the first adder circuit and the instructor-side speaker.

Further, according to the present invention, each of the output means includes an output terminal for outputting an output signal of the classroom microphone, and the instructor studio has an input terminal connected to each of the output terminals, and an input terminal of each of the input terminals. It may include the first addition circuit for adding the output signal and a second addition circuit to be provided to the instructor speaker.

[Action]

Each classroom delays the output signal of the classroom microphone with a delay circuit. The echo canceller deletes the audio signal generated by the student himself that is inserted between the classroom-side receiving means and the classroom-side speaker and added to one of the radio waves based on the output signal of the delay circuit and added back to the instructor's audio signal. .

In addition, each classroom transmits the output signal of the microphone on the classroom side to the instructor's studio via the communication satellite using the other one radio wave by the classroom transmitting means, and the instructor's studio transmits the output signal by the other one radio wave by the instructor receiving means. An audio signal from each classroom is received via a communication satellite and provided to the first addition circuit and the speaker on the instructor side.

Furthermore, each classroom outputs the output signal of the classroom microphone from the output terminal, the teacher studio inputs the audio signal from each output terminal to the input terminal, and the output signal of this input terminal is added by the second addition circuit. In some cases, the signal is supplied to the first addition circuit and the speaker on the instructor side.

As described above, the voice signal generated by the returning questioner himself added to the voice signal of the instructor in one radio wave can be erased, and the conversation can be performed very easily.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a remote lecture system according to an embodiment of the present invention. In FIG. 1, the remote lecture system is composed of a plurality of classrooms 2.
When, a lecturer studio 1 for instructor lectures against student of the plurality of classes, lecturer Studio 1 includes a microphone 4 ₁ and lecturer microphone outputs audio signals of instructors, classrooms input means for inputting an audio signal from the 2, an adding circuit 6 as a first adding circuit for adding the output signal of the input means and the output signal of the microphone 4 _1, a communications satellite 11 by one of the radio wave f ₁ a transmitter ₇₁ as a lecturer transmitting means for transmitting the output signal of the adder circuit 6 in each classroom 2 through, and a speaker 5 ₁ as a lecturer speaker for outputting an output signal of the input means as voice, each Classroom 2
It includes a receiver ₈₂ as classrooms side receiving means for receiving an output signal of the transmitter ₇₁ via the communications satellite 11 via radio waves f _1, receiver
8 _second output signal and the speaker 5 ₂ as classrooms side speaker for outputting a voice, a microphone 4 ₂ as classrooms side microphone for outputting an audio signal of the student, the microphone
And output means for outputting the output signal of ( ₂ ) to the instructor-side studio 1.

Here it is an aspect of the present invention, each classroom 2, inserted into the delay between the delay circuit 10 to the output signal of the microphone 4 ₂ is input is branched, the receiver ₈₂ and the speaker 5 ₂ radio waves f ₁ based on the output signal of the circuit 10 is to including an echo canceller 9 for erasing the audio signal generated in the student himself returning is added to the audio signal of the instructor.

Further, each output unit includes a transmitter 7 ₂ by one other radio f ₂ as classrooms side transmission means for transmitting via the communications satellite 11 to the output signal of the microphone 4 ₂ lecturer studio 1,
It said input means adds receives the output signal of each transmitter 7 ₂ via the communications satellite 11 by a radio wave f ₂ circuit 6 and the speaker 5 ₁
It includes a receiver ₈₁ as a lecturer receiving means for providing a.

Delay circuit 10, until one of the signals branched from the output signal of the microphone 4 ₂ is returned to the transmitter 7 _2, receiver _81, the adder circuit 6 and the transmitter 7 ₁ receiver 8 ₂ via the Is given to the other split signal.

The operation of the remote lecture apparatus having such a configuration will be described.

In Figure 1, arranged echo canceller 9 in the receiving circuit of each classroom 2, audio signal of the questioner is input to the transmitter 7 ₂ via the microphone 4 _2, the echo canceller 9 through the delay circuit 10 Is input to the receiving side input unit.
The transmission-side input of the echo canceller 9, the output signal of the receiver ₈₂ is input, the signal from the transmitting side input of the echo canceller 9, creates a pseudo echo as a reference signal a signal from the received signal transmission Subtracting from the input, only the voice signal of the interrogator is deleted. Only teacher audio from lecturer studio 1 is emitted from the speaker 5 _2. The echo canceller 9 in the classroom 2 other than the classroom where the questioner is located is not erased, and the instructor can listen to both voices of the questioner.

FIG. 2 is a block diagram of a remote lecture system according to another embodiment of the present invention. In FIG. 2, 21 is an output terminal, 22 is an input terminal, and 23 is an adder circuit. FIG. 2 shows a case where a ground line is used without using the communication satellite 11 when a question is issued from each classroom 2A to the instructor's studio.

〔The invention's effect〕

As described above, the present invention can eliminate the audio signal generated by the questioner himself who is added back to the instructor's audio output in one radio wave from the lecture studio,
There is an excellent effect that makes conversation very easy.

[Brief description of the drawings]

FIG. 1 is a block diagram of a remote lecture system according to an embodiment of the present invention. FIG. 2 is a block diagram of a remote lecture system according to another embodiment of the present invention. FIG. 3 is a block diagram of a conventional remote lecture system. 1, 1A, 1B ...... lectures side studio, 2, 2A, 2B ...... classroom (questioner), 4 _1, 4 ₂ ...... microphones, 5 _1, 5 ₂ ...... speakers, 6,23 ...... adder circuit, 7 ₁ , 7 ₂ … Transmitter, 8 ₁ , 8 ₂
... Receiver, 9 ... Echo canceller, 10 ... Delay circuit, 11 ... Communication satellite, 21 ... Output terminal, 22 ... Input terminal.

Claims (3)

(57) [Claims] An instructor-side studio for providing a lecturer with a lecturer for a remote lecturer for a student in the classroom, wherein the lecturer-side studio outputs a lecturer's voice signal to the lecturer. And input means for inputting audio signals from each classroom, a first addition circuit for adding the output signal of the instructor microphone and the output signal of this input means, and a communication satellite by one radio wave Instructor-side transmitting means for transmitting the output signal of the first adder circuit to each of the classrooms, and an instructor-side speaker for outputting the output signal of the input means as audio, wherein each of the classrooms is provided by the one radio wave A classroom-side receiving means for receiving the output signal of the instructor-side transmitting means via the communication satellite, a classroom-side speaker for outputting the output signal of the classroom-side receiving means as voice, and a voice signal of the student In the remote lecture system including a classroom microphone that outputs the classroom microphone, and an output unit that outputs an output signal of the classroom microphone to the instructor studio, the output signal of the classroom microphone is branched into each classroom. A delay corresponding to the time required for one of the branched signals to return from the output means to the classroom-side receiving means via the input means, the first adding circuit, and the instructor-side transmitting means is branched off. And a delay circuit to be added to the other signal, and a signal inserted between the classroom-side receiving means and the classroom-side speaker, added to the instructor's voice signal by the one radio wave based on the output signal of the delay circuit, and returned. A remote lecture system comprising: an echo canceller for erasing an incoming voice signal generated by the student. 2. Each of the output means includes classroom-side transmission means for transmitting an output signal of the classroom-side microphone to the instructor-side studio via the communication satellite by another one radio wave, and the input means comprises the classroom-side transmission means. 2. The remote lecture system according to claim 1, further comprising an instructor-side receiving means for receiving an output signal of each of said output means via said communication satellite by another one radio wave and supplying said output signal to said first adder circuit and said instructor-side speaker. . 3. Each of the output means includes an output terminal for outputting an output signal of the classroom microphone. The instructor studio includes an input terminal connected to each of the output terminals, and an output of each of the input terminals. 2. The remote lecture system according to claim 1, further comprising a first addition circuit for adding a signal and a second addition circuit for providing the first addition circuit to an instructor speaker.