JPH0123024B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a method for holding a conference with a large number of people in the same room;
The present invention relates to a directional transmitting/receiving unit that has an integrated structure of a microphone section and a speaker section for use in lectures, seminars, meetings with remote locations, etc.

Conventionally, in meetings, lectures, seminars, or remote conferences involving many people, the directivity of both speakers and microphones is often used, so that the sound amplified from the speakers is difficult to be picked up by the microphones, and on the other hand, the speaker's Place the speakers on the ceiling so that their directivity points toward the floor so that voices are picked up.
In addition, the conventional method of microphones is to allocate one normal unidirectional microphone to each person and install the microphone so that its directivity points toward each speaker. Furthermore, when multiple microphones were assigned to each person, each microphone was rotated and used to face the speaker.

In such a method, the following processing must be performed on the amplifier and the like in terms of operation and communication quality, and even then, satisfactory results have not been obtained. First, the phenomenon in which the sound amplified by a speaker is picked up by a microphone is called the ringing phenomenon, and it is said that the ringing margin is large when the amount of sound that is picked up by the microphone is small. The following methods are used to prevent this noise phenomenon.

(1) Since there is a proportional relationship between the number of attendees and the number of microphones, the sound margin depends on the number of microphones.
For this reason, in the case of a large number of people, the noise margin becomes smaller and the noise phenomenon is more likely to occur. Therefore, in order to prevent ringing under such conditions, the speaker must either speak closer to the microphone or the volume of the voice received from the speaker must be lowered. Therefore, the speaker was very annoying, and attendees sitting far from the speaker could not hear the speaker at a sufficient volume.

(2) An audio switch circuit was installed in the amplifier, increasing its insertion loss. However, due to the large amount of insertion loss, there were drawbacks such as deterioration in call quality such as cutting off at the beginning of a conversation and interruption performance.

(3) In cases where the microphone is not fixed in order to allow speakers to speak close to the microphone or to make effective use of the conference room, and the microphone is simply placed on the conference table for each meeting. In this system, the directivity direction of the microphone and the distance from the speaker (hereinafter referred to as the "talking distance") change each time the microphone is installed, and as a result, the sound margin changes and becomes unstable each time it is installed. Second, since microphone sound collection is inversely proportional to speaking distance, there is a constraint that the speaking distance must be at least 30 cm in order to collect sufficient sound, which can significantly impede a comfortable conference. However, the drawback was that the speaker was easily fatigued. Additionally, since a directional microphone is used, if the speaker turns to the side and speaks, the volume picked up will be small, making it extremely difficult to hear. Thirdly, the S/N ratio, which is one element of call performance, is proportional to the number of attendees and the number of microphones, so in meetings, lectures, seminars, etc. with a large number of people, the number of microphones will inevitably increase. However, only the room noise picked up by each microphone and the noise of the microphone amplifier are added together, resulting in a deterioration of the S/N ratio. Fourth, the method of simply placing a microphone on a conference table and conducting a conference has the following drawbacks.

(1) It was easy to pick up vibrations from the table, which degraded call quality.

(2) Because the speaker drew the microphone closer to him when speaking, it was easy to pick up the friction noise between the table and the microphone stand, which degraded the quality of the call.

(3) Become a nuisance of meeting materials, etc.

(4) The sound of turning over meeting materials and the sound of pencils being placed were easily picked up, which degraded call quality.

An object of the present invention is to arrange a directional transmitting/receiving unit in which a microphone group section and a speaker section are integrally constructed as described below so that the linear mounting base of the directional transmitting/receiving unit is perpendicular to the floor surface. By doing so, the above-mentioned drawbacks are eliminated and conference attendees can conduct natural meetings, lectures, seminars, etc. with good call quality without any restrictions. The aim is to provide units.

Describing the structure of the present invention, the present invention includes a linear mounting base, and a plurality of omnidirectional microphone units arranged on the linear axis of the mounting base at intervals of half a wavelength of the highest frequency sound wave handled by this unit. and a microphone group section whose length is equal to the wavelength of the lowest frequency sound wave handled by the unit, and a microphone group section on the same axis from the microphone group section on the axis of the linear mounting base. This is a directional transmitting/receiving unit that is constructed as an integral structure with a speaker section in which a speaker serving as a receiving sound source is arranged at a position separated by an arbitrary distance.

The effects of the present invention include the following.

(1) Unlike in the past, the number of conference attendees and the number of microphones are not proportional, and a single directional transmitter/receiver unit can collect sufficient sound, allowing for greater sound margin and S /N ratio is also improved.

(2) The microphone is not installed on the conference table as in the past, but is installed on the floor away from the conference table, so it does not pick up sound reflections from the conference table, etc., and has a large sound margin. At the same time, the vibration of the conference table, the friction noise when pulling the microphone stand,
The sound of flipping through conference materials is also inevitably removed.

(3) Since the sound margin is large, an audio switch circuit is not required, contributing to lower system costs. Furthermore, even when a voice switch circuit is provided, insertion loss can be reduced, and speech quality does not deteriorate.

(4) The directivity of the transmitter/receiver unit is shaped like a horizontal disk centered on a line perpendicular to the floor, and by placing the speaker on the circumference in a horizontal plane perpendicular to the axis of the vertical line, Even if the speaker is speaking sideways or the distance of the call changes, sufficient sound can be captured, and since the receiving sound source is located in the center of the attendees,
Meetings, lectures, seminars, etc. can be held in an extremely natural and comfortable manner.

The present invention will be explained below by way of examples with reference to the drawings.

Fig. 1 is a front view of an embodiment of the directional transmitting/receiving unit of the present invention, Figs. 2 and 3 are diagrams showing an embodiment of the speaker section in which the speaker mounting method is different from that of Fig. 1, and Fig. 4. 5 shows an embodiment of the circuit configuration of the directional transmitting/receiving unit of the present invention, and FIG. 5 shows an embodiment of the circuit configuration in which the directional transmitting/receiving unit includes a transmitting amplifying circuit and a receiving amplifying circuit.

In FIG. 1, 1 is a mounting base, 2 is a linear mounting base, 3 is a microphone group section, 4-1 to 4-n are microphone units, 5 is a speaker section, and 6 is a speaker.

In this embodiment, the microphone units 4-1 to 4-n are very small omnidirectional electret microphone units, and are arranged so that the directivity of the microphone group 3 can be obtained sufficiently within the frequency band handled. The number of microphones arranged in a straight line was arranged at intervals of half a wavelength of the highest frequency sound waves to be handled, and the number of microphones was set so that the length of the array of these microphones was equivalent to the wavelength of the lowest frequency sound waves to be handled. . For example, when used in the telephone band, it has been confirmed through experiments that sufficient directivity can be obtained if the distance between the microphone units is several centimeters, and the total length of the array of microphone units is about 1 m or more.

The speaker section 5 has one dynamic speaker 6 built in, and is arranged so that the front surface of the opening of the speaker 6 faces the microphone group section 3.

The linear mounting base 2 is for fixing the microphone group section 3 and the speaker section 5 so that the front surface of the speaker opening can be placed on the axis of the microphone group section 3.

The distance between the speaker section 5 and the microphone group section 3 is such that the sound amplified from the speaker can be heard uniformly and at sufficient volume by the listener, but the sound is difficult to be picked up by the microphone group section 3.

In Fig. 2, 5 is a speaker section, 6-1 to 6
-4 is a speaker. Figure 2a is a front view;
Figure b is a plan view. The speaker section 5 has four built-in dynamic speakers, and the speaker section 5 has four built-in dynamic speakers.
The front surfaces of the openings 1 to 6-4 are mounted horizontally at 90 degrees with respect to the linear mounting base 2 shown in FIG.

In FIG. 3, 5 is a speaker section, 6 is a speaker, and 7 is a conical or pyramidal reflector for the purpose of diffusing a received sound source.

Next, an embodiment of the circuit configuration of the directional transmitting/receiving unit of the present invention will be described with reference to FIG. In Fig. 4, 4-1 to 4-n are microphone units, 6 is a speaker, 8-1 to 8-n are preamplifiers, 9 is a mixer circuit, 10 is a speech output terminal,
11 is a reception input terminal. Now, the voice of the speaker is collected by all microphone units 4-1 to 4-n, and amplified by each preamplifier 8-1 to 8-n. The gain of the preamplifier that amplifies the sound picked up by each microphone can be reduced in inverse proportion to the number of microphone units. Therefore, even if the number of microphone units increases, a good S/N ratio can always be kept constant, and a large sound margin can always be obtained.
The voice of the speaker amplified by each of the preamplifiers 8-1 to 8-n is mixed by a mixer circuit 9 and output to a transmission output terminal 10. On the other hand, receive input terminal 1
The reception signal given to the speaker 1 is input to the speaker 6.

In Fig. 5, 4-1 to 4-n are microphone units, 6 is a speaker, 8-1 to 8-n are preamplifiers, 9 is a mixer circuit, 10 is a transmitting output terminal, 11 is a receiving input terminal, and 12 is a receiving terminal. transmitting amplifier circuit,
13 is a receiving amplifier circuit.

With the above-described configuration and operation, the directional transmitting/receiving unit of the present invention can always provide a stable and large sound margin regardless of the number of speakers, that is, the number of microphones, and has sufficient reception volume while speaking. According to the experimental results of this example, the speaker's voice is uniformly and sufficiently picked up even if the speaker is 1 to 4 meters away from the directional transmitting/receiving unit, and the speaker can speak without any restrictions. I was able to hold a conference that was extremely natural and had good call quality.

As explained above, according to the present invention, by arranging a plurality of microphone units in a straight line at arbitrary equal intervals and by arranging the speakers on the same axis on which the microphone units are arranged, it is possible to obtain sound margin. The effect is that the speaker can speak without being affected by the number of speakers, that is, the number of microphones, and that the speaker can speak without being restricted by the speaking position, etc., and can obtain a communication performance that allows for a good S/N ratio and sufficient volume to be heard. .

[Brief explanation of drawings]

FIG. 1 is a front view of an embodiment of the directional transmitting/receiving unit of the present invention, FIGS. 2 and 3 are an embodiment in which the speaker mounting method of the speaker section shown in FIG. FIG. 5 shows an example of the circuit configuration. The symbols used in the drawings indicate the following. 1... Installation stand, 2... Linear mounting base, 3...
Microphone group section, 4-1 to 4-n...Microphone unit, 5...Speaker section, 6...Speaker, 7...Conical or pyramidal reflector, 8-1
~8-n...Preamplifier, 9...Mixer circuit,
10... Sending output terminal, 11... Receiving input terminal,
12... Sending amplifier circuit, 13... Receiving amplifier circuit.

Claims (1)

[Claims] 1. A linear mounting base, and a plurality of omnidirectional microphone units arranged on the linear axis of this mounting base at intervals of half a wavelength of the highest frequency sound wave handled by this unit, and the length of the arrangement is equal to the length of the unit. a microphone group section whose wavelength is equivalent to the lowest frequency of the sound wave handled by the device; and a speaker serving as a receiving sound source located on the same axis at an arbitrary distance from the microphone group section on the linear mounting base axis. What is claimed is: 1. A directional transmitting/receiving unit, characterized in that it is configured as an integral structure with a speaker section in which a speaker section is arranged.