JPH02162999A - Ultrasonic communication equipment - Google Patents

Abstract

PURPOSE:To deliver a voice only to a prescribed person among lots of persons with the use of an inexpensive receiver without giving adverse effect onto other electric equipment and being interfered by a person or a thing. CONSTITUTION:A voice signal So corresponding to an English voice is supplied from a microphone 2 to an AM modulation circuit 3 and a periodic signal Fo whose frequency is fo is supplied from an oscillator 4. Moreover, an AM modulation signal is generated by an AM modulation circuit 8 and a French microphone 7 generating a voice signal S1 corresponding to a French voice and added to generate a synthesis signal S2 and the synthesis signal S2 is fed to a ferrite vibrator 11. Thus, the simultaneous translation voice in English voice is listened to for a person mounted with an earphone 13 of this embodiment in, a conference. Furthermore, the simultaneous translation voice in French voice is listened to by switching the center frequency of a band pass filter 16 to a frequency f1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic communication device suitable for use in transmitting simultaneous interpretation audio only to desired persons at, for example, international conferences.

[Summary of the invention]

The present invention provides an ultrasonic communication device suitable for use in transmitting simultaneous interpretation audio only to desired persons at international conferences, for example, which includes a transmitter that sends out ultrasonic waves modulated with an audio signal, and a transmitter that transmits the ultrasonic waves using electricity. By providing a receiver having a conversion means for converting into a signal and a demodulation circuit for demodulating the audio signal from the electrical signal, it is possible to use an inexpensive receiver without adversely affecting other electrical equipment. This system allows audio to be transmitted only to a designated person among many people using ultrasound as a medium, without being blocked by people or objects.

Further, the present invention provides a transmitter that sends out an ultrasonic wave of a predetermined frequency that is amplitude-modulated with an audio signal, and a receiver that has an oscillator and a vibration element that generate a signal of the same frequency as the predetermined frequency. By simultaneously exciting the vibrating element with a sound wave and an oscillator to extract an audible sound corresponding to the audio signal, the receiver can be made more compact.

[Conventional technology]

For example, at an international conference, you may want to convey simultaneous interpretation audio only to those who request it, or in tourist information, you may want to convey audio guidance only to tour participants. There is a growing need for voice transmission devices that can convey voices that only consist of. Among such audio transmission devices, there are two known types of wireless audio transmission devices: (1) a device that transmits voice using radio waves as a medium, such as a transceiver or a wireless receiver, and (2) a device that transmits voice using light such as infrared rays as a medium.

[Problem to be solved by the invention]

However, devices using radio waves as a medium may have an adverse effect on electrical equipment such as other television receivers and so-called OA equipment, and have disadvantages in that the cost of receivers such as wireless receivers is high. Furthermore, the device using light as a medium has the disadvantage of becoming unusable if the light is blocked by a person or object.

In view of this, the present invention proposes an inexpensive device that can transmit audio only to a designated person among many people without adversely affecting other electrical equipment or being blocked by people or objects. The purpose is to

[Means to solve the problem]

The first ultrasonic communication device according to the present invention modulates the audio signal S0 (for example, AM modulation or FM
a transmitter (1) that sends out a modulated ultrasonic wave SS, and a conversion means (14) that converts the ultrasonic wave SS into an electrical signal S2.
and a receiver (13) having a demodulation circuit (I7) that demodulates the audio signal S0 from the electrical signal S2.

Further, the second ultrasonic communication device according to the present invention is, for example, the first ultrasonic communication device.
As shown in the figure and FIG. 2, a transmitter (1) that sends out an ultrasonic wave SS of a predetermined frequency 10 amplitude-modulated with the audio signal S0, and an oscillator (24) that generates a signal of the same frequency as the predetermined frequency f0. a receiver (1) having a vibration element (21);
9), and its ultrasonic SS and its oscillator (24)
By simultaneously vibrating the vibrating element (21), an audible sound H3 corresponding to the audio signal S0 is extracted.

[Effect]

According to the first ultrasonic communication device, the transmitter (1) converts a predetermined voice into the voice signal S0 and transmits the ultrasonic wave SS modulated by the voice signal S0, and the receiver (1) Here, by converting the ultrasonic wave SS into an electric signal S2 and demodulating the audio signal S0, the audio can be transmitted only to the person who has the receiver (1υ) using the ultrasonic wave as a medium.

Moreover, according to the second ultrasonic communication device, the receiver (19)
By simultaneously exciting the vibrating element (21) with the amplitude-modulated ultrasonic wave SS of frequency f0 and the oscillator (24) that generates a signal of frequency f0, an audio signal that is a signal of the frequency difference between them is generated. Audible sound H3 corresponding to S0 is directly extracted and emitted.

(Embodiment) An embodiment of the ultrasonic communication device according to the present invention will be described below with reference to Fig. 1. In this embodiment, the present invention is applied to a simultaneous interpretation system used at international conferences.

FIG. 1 shows the ultrasonic communication device of this example, and in this FIG. 1, (1) and (13) generally indicate a transmitter and an earphone, respectively. In this transmitter (1),
(2) is a microphone for English speech, (3) is an AM modulation circuit, and (4) is an oscillator with an oscillation frequency f of about 20kHz or more (for example, about 40kHz)12), and the AM modulation circuit (3) The microphone (2) supplies an audio signal S0 corresponding to English speech to the oscillator (4).
) supplies a periodic signal F0 of frequency f0.

In this case, if the frequency of the audio signal S0 is f, the audio signal S0 and the periodic signal F0 are each 50=CO52πf
3t, Fo=cos2πfot −・−・
The AM modulation circuit (3) can be expressed as (14ASo)Fo=(1+Acos2gf,t)co using a constant A.
An AM modulated signal expressed as s2π fot −(2) is generated. This AM modulated signal is supplied to one input terminal of an adder circuit (6) via an amplifier circuit (5).

(8) is an AM modulation circuit; (9)
is an oscillator that generates a periodic signal F+ with a frequency r+ (for example, about 75 kHz) higher than the frequency f0 by 20 kHz to 30 kHz or more, and the AM modulation circuit (8) uses a constant B to generate, for example, (1+Bs,)F,... ...(3) is generated, and this AM modulated signal is supplied to the other input terminal of the adder circuit (6) via the amplifier circuit (10). This adder circuit (6) adds the AM modulation signal expressed by equation (2) and the AM modulation signal expressed by equation (3) to generate a composite signal S2, and this composite signal S2
is supplied to the ferrite resonator (11).

From this ferrite resonator (11), frequencies f0 and f
An ultrasonic wave SS corresponding to the composite signal S2 multiplexed and modulated in , is emitted to the earphone (13) side.

Further, (12) is a horn for emitting the ultrasonic waves SS to the outside with high efficiency.

In addition, when the frequency of the ultrasonic SS is several tens of kHz as in this example, a bimorph type vibrator made by bonding two PZT (electrostrictive vibrators) or the like is used instead of the ferrite vibrator (11). Good too. Furthermore, several hundred ultrasonic SS
When using ultrasonic waves with a frequency of about kHz to 2 MH2, a barium titanate ceramic vibrator, for example, may be used instead of the ferrite vibrator (11).

Furthermore, in the earphone (13) shown in FIG.
1) Convert the ultrasonic waves SS emitted from the unit into a composite signal S2 which is an electric signal, and send this composite signal S2 to the amplifier circuit (15).
through a bandpass filter (16) with a center frequency of 10
supply to. Note that a small ultrasonic microphone may be used instead of this ferrite vibrator (14).

Equation (2) filtered by the bandpass filter (16)
The audio signal S0 is demodulated by supplying the AM modulated signal (1+ASo) Fo represented by to the detection circuit (17) and performing, for example, envelope detection, and the small speaker (18) outputs the English signal corresponding to the audio signal S0. Voice or audible sound H3
is emitted. The detection circuit (17) may be composed of, for example, a local oscillation circuit with an oscillation frequency of 10, a mixer, and a low-pass filter.

Therefore, for example, a person wearing the earphones (13) of this example at a meeting can listen to simultaneous interpretation audio using English audio. Furthermore, by switching the center frequency of the bandpass filter (16) to f, it is also possible to listen to simultaneous interpretation audio using French audio. Furthermore, the earphones (1
In 3), it is desirable that the entire device be compact enough to be worn in the ear, but in 1, for example, only the small speaker (18) may be packed in a shape that can be worn in the ear.

As mentioned above, in this example, simultaneous interpretation audio in English and French is transmitted using ultrasound as a medium, but ultrasound generally does not have a negative effect on television receivers or OA equipment, and is safe for people and people. It also conveys information to the hidden parts of things.

Therefore, according to this example, simultaneous interpretation audio can be transmitted only to the person wearing the earphone (13) among many people without adversely affecting other electrical equipment or being blocked by people or objects. There is profit. In addition, the earphone of this example (13
) has the advantage of being cheap to manufacture.

Next, another embodiment of the present invention will be described with reference to FIG.

FIG. 2 generally shows an ultrasonic earphone (19) that can be worn on the ear as a receiver in this example. 2)
AM modulated signal (1+AS,)F.

It is assumed that an ultrasonic wave SS corresponding to is emitted. In this ultrasonic earphone (19), (20) is a conductive metal frame, and this metal frame (20) has a diameter of several mm to 20 m.
After inserting the ferrite vibrator (21) with a diameter of about m, the ferrite vibrator (21) is fixed using a nut (23) via an insulating ring (22).

Further, (24) is an oscillator with an oscillation frequency f0, and the two output terminals of this oscillator (24) are connected to lead wires (25), respectively.
) and (26) to the metal frame (20) and the back surface of the ferrite vibrator (21). And this oscillator (
24), the ferrite oscillator (21) has CO52π
A sinusoidal voltage represented by f0 is applied to vibrate the ferrite vibrator (21). In this case, the ferrite vibrator (21) receives ultrasonic waves SS supplied from the outside.
Since the ferrite oscillator (21) is also excited by
cos2πf, t= (1+Aso)cos2πfot
Xcos2gfoL= (1+^5o)(1+cos
4 z f, t)/2=(1+ASo)/2+(1+A
So) cos4 πfot/2 ・---・ ・
−(4). However, if the frequency of the audio signal input from the microphone (2) in the example in Figure 1 is f, then 5
a=cos 2x fst. The second of formula (4)
The audio corresponding to the term has a frequency of 2f0 (that is, approximately 80 kHz in this example) and is therefore inaudible to the ear. On the other hand, the expression (
The sound corresponding to the first column of 4) is the English sound input from the microphone (2) in the example of FIG. 1, that is, the audible sound H3.

This means that the audible sound H3 corresponding to the voice/signal S0 is extracted from the ultrasonic wave SS by the ferrite vibrator (21) and emitted to the ear. Therefore, by wearing the ultrasonic earphones (19) of this example in one's ears, one can listen to simultaneous interpretation audio in English.

It can be seen that the ferrite vibrator (21) in the ultrasonic earphone (19) of this example also functions as the bandpass filter (16) and detection circuit (17) in the example of FIG.

Therefore, according to this example, there is an advantage that the receiver side of the ultrasonic communication device can be further downsized.

In the above embodiment, AM modulated ultrasonic waves SS are used as a medium for transmitting audio, but AM modulation may be SSB communication in addition to DSB communication, and further,
The ultrasonic wave may be subjected to FM modulation or the like using an audio signal.

As described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various configurations may be adopted without departing from the gist of the present invention.

〔Effect of the invention〕

Since the ultrasonic communication device according to the present invention transmits sound using ultrasonic waves as a medium as described above, it uses an inexpensive receiver and does not adversely affect other electrical equipment and can be shielded from people or objects. There is an advantage in that the voice can be transmitted only to a predetermined person among many people without being disturbed.

Furthermore, if a receiver is configured with an oscillator and a vibrating element, and the vibrating element is simultaneously excited by ultrasonic waves and its oscillator, an audible sound corresponding to an audio signal is extracted.
There is an advantage that the receiver can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of an ultrasonic communication device according to the present invention, and FIG. 2 is a block diagram including a partial cross-sectional view showing essential parts of another embodiment of the present invention. (1) is a transmitter, (13) is an earphone, (14) is a ferrite vibrator, (17) is a detection circuit, (19) is an ultrasonic earphone, (21) is a ferrite vibrator, (24) is an oscillator It is.

Claims (1)

[Claims] 1. A transmitter that sends out ultrasonic waves modulated with audio signals, conversion means that converts the ultrasonic waves into electrical signals, and a demodulation circuit that demodulates the audio signals from the electrical signals. An ultrasonic communication device characterized by comprising a receiver. 2. A transmitter that sends out ultrasonic waves of a predetermined frequency that are amplitude-modulated with an audio signal, and a receiver that includes an oscillator and a vibration element that generate a signal of the same frequency as the predetermined frequency, and the ultrasonic wave and the oscillator An ultrasonic communication device characterized in that an audible sound corresponding to the audio signal is extracted by simultaneously vibrating the vibrating element.