JP2000004500A - Speaker system for deciding azimuth automatically - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speaker system where a position of a listener is calculated and a radiation direction of acoustic vibration is directed toward the listener in matching with the movement of the listener. SOLUTION: The speaker system is provided with a parametric speaker 10, a detector 20 that detects reflection vibration resulting from emitted acoustic vibration reflected from a listener 1 in front, a calculation device 30 that calculates a deviation in the listener 1 with respect to a radiation axis of the acoustic vibration based on a signal generated in the parametric speaker and the reflection vibration and a direction adjustment device 40. Thus, the radiation direction of the acoustic vibration is directed in the direction of the listener 1 based on the calculation result of the calculation device 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loudspeaker device using a parametric loudspeaker, which can calculate the position of a listener and can direct the radiation direction of acoustic vibration to the listener in accordance with the movement of the listener. .

[0002]

2. Description of the Related Art A loudspeaker (parametric loudspeaker) which synthesizes an audible sound from a modulated ultrasonic wave having a finite amplitude level by using the nonlinearity of air with respect to the ultrasonic wave.
It has been known. A parametric speaker is a speaker having excellent directivity.

[0003] A parametric speaker will be described with reference to FIG. The audio signal from the audio generator 81 is output from the high-frequency
The amplitude is modulated by the amplifier, amplified by the amplifier, and the electroacoustic transducer 8
5 is input. When an acoustic vibration that is a modulated ultrasonic wave is radiated into the air at a finite amplitude level from the electroacoustic transducer 85,
Due to the non-linear characteristics of air, ultrasonic waves cause a kind of non-linear interaction, and an original signal wave (voice signal) having sharp directivity in the air is demodulated.

Here, a parametric phenomenon, which is a kind of nonlinear acoustic phenomenon of gas, will be briefly described. When the speaker is driven at two frequencies, f1 and f2, f1 and f2
The (temporary wave) causes interference due to the nonlinear characteristics of the medium (air), and the frequency of the sum and difference thereof, that is, f1 + f2 and f2-
A wave (secondary wave) having f1 is generated. Therefore, if f1 + f2 is set to an ultrasonic wave and f2-f1 is set to an audio frequency, the generated audible sound can be heard.

[0005] As a technique using the parametric speaker, Japanese Patent No. 2665007 discloses the presence or absence of a listener by detecting the reflected wave of the acoustic vibration radiated from the parametric speaker from the listener. Is described.

[0006]

However, according to the technique described in the publication of Japanese Patent No. 2665507, only the presence or absence of a listener is determined, so that the listener moves and moves out of the audible area of the acoustic radiation. In some cases, the listener cannot hear the emitted sound.

Accordingly, an object of the present invention is to provide a speaker device capable of calculating the position of a listener and directing the radiation direction of acoustic vibration to the listener in accordance with the movement of the listener.

[0008]

According to the present invention, there is provided an automatic azimuth determining speaker device comprising: an audio signal output unit for outputting an audio signal; a high frequency output unit for outputting a high frequency signal having a predetermined frequency; And amplitude modulation means for amplitude-modulating the high-frequency signal and outputting an amplitude-modulated signal,
A parametric loudspeaker comprising amplification means for amplifying the amplitude-modulated signal, radiating means for radiating the amplified amplitude-modulated signal as ultrasonic acoustic vibration, and listening in front of the radiated acoustic vibration Detecting means for detecting reflected vibration reflected from a person or the like, and a signal generated in the parametric speaker and the detected reflected vibration are input, and a signal generated in the parametric speaker and the reflected vibration Calculation means for calculating the deviation of the listener or the like from the radiation axis of the acoustic vibration, and instruction means for directing the radiation direction of the acoustic vibration to the direction of the listener or the like based on the calculation result of the calculation means. It is characterized by having.

[0009] The calculating means may include first frequency detecting means for detecting an energy amount of the amplitude modulated signal having a first frequency, and an energy amount of the amplitude modulated signal having a second frequency. Second frequency detecting means for detecting, third frequency detecting means for detecting the energy amount of the reflected vibration having the first frequency, and detecting the energy amount of the reflected vibration having the second frequency. A fourth frequency detecting means, a first circuit for obtaining a difference between the energy amounts detected by the first frequency detecting means and the third frequency detecting means, and obtaining a first reflectance from the difference; Calculating a difference between the energy amounts detected by the second frequency detecting means and the fourth frequency detecting means,
A second circuit for obtaining a second reflectance from the difference; obtaining a difference between the first reflectance and the second reflectance; and calculating a difference between the listener and the like with respect to a radiation axis of the acoustic vibration from the difference. And a third circuit for obtaining a shift.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a speaker device according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an embodiment of a speaker device according to the present invention.

The embodiment of the present invention includes a super-linear acoustic vibration radiation circuit 10, an acoustic detector 20, and a position calculating device 30.
And a radiation direction adjuster 40.

The super-straight acoustic vibration radiating circuit 10 receives a voice generator 11 for outputting a voice signal, a high frequency generator 12 for outputting a carrier signal, and a voice signal and a carrier signal output from these components. An amplitude modulator 13 that outputs an amplitude-modulated signal, an amplitude-modulated signal that is output is input, and an amplifier 14 that sufficiently amplifies and outputs the signal, and an amplified amplitude-modulated signal that is input and radiates as acoustic vibration. This is a parametric speaker including the electroacoustic transducer 15.

The acoustic detector 20 detects the reflected vibration of the acoustic vibration radiated from the electroacoustic transducer 15 and reflected by the listener 1, and the position calculator 30 calculates the reflected vibration and the amplitude detected by the acoustic detector 20. The direction and distance of the listener 1 are calculated based on the modulated wave signal. In order to make the transmitting and receiving positions the same, if the electroacoustic transducer 15 and the acoustic detector 20 use the same element capable of transmitting and receiving ultrasonic waves, the accuracy of calculating the direction and the distance of the listener 1 is improved. .

FIG. 2 shows the configuration of the position calculating device 30.
FIG. 2 is a block diagram illustrating a configuration of the position calculation device 30.

Referring to FIG. 2, the position calculating device 30 comprises:
It comprises a measuring unit 2 and a control unit 3.

The measuring section 2 receives the amplitude modulated signal from the amplifier 14 and the reflected vibration from the acoustic detector 20.

The frequency detectors 51 and 53 detect amplitude-modulated signals of frequency A and frequency B, respectively. The frequency detectors 52 and 54 detect the reflected vibration of the frequency A and the frequency B, respectively. Note that the frequency detector is a device that detects the amount of frequency energy.

The difference circuit 55 includes frequency detectors 51 and 5
2 is obtained, and the reflectance is obtained from the difference. The difference circuit 56 calculates the difference between the frequency energies obtained from the frequency detectors 53 and 54, and calculates the reflectance from the difference. The difference circuit 58 calculates the deviation of the listener 1 with respect to the radiation axis of the acoustic vibration from the difference between the reflectances obtained by the difference circuits 55 and 56.
The timer counter circuit 57 includes frequency detectors 53 and 54
Then, the delay time of the reflected vibration with respect to the amplitude-modulated signal to be detected and the acoustic vibration radiated from the reflected vibration is calculated.

Further, by setting one of the frequency A and the frequency B detected by the measuring unit 2 to the same frequency as the carrier signal, the measuring unit 2 described with reference to FIG.
One frequency detector can be omitted and three can be provided. This will be described with reference to FIG. FIG. 3 is a block diagram showing a configuration of another example of the measuring unit 2. As shown in FIG.

In this example, the amplitude modulated signal having the frequency A is supplied from the amplifier 14, the carrier signal having the frequency B is supplied from the high frequency generator 12, and the acoustic detector 20 is supplied to the measuring section 2. A and frequency B reflected vibrations are input. Note that the frequency A and the frequency B are different frequencies.

Referring to FIG. 3, the frequency detector 61 includes:
The amplitude modulated signal having the frequency A is detected, and the frequency
Detects the reflected vibration of the frequency A,
Detects the reflected vibration of frequency B.

The difference circuit 64 includes frequency detectors 61 and 6
2 is obtained, and the reflectance is obtained from the difference. The carrier signal (frequency B) is input to the difference circuit 65, and a difference from the frequency energy obtained from the frequency detector 63 is obtained, and a reflectance is obtained from the difference. The difference circuit 67 obtains a difference between the reflectances obtained by the difference circuits 64 and 65, and calculates a deviation of the listener 1 with respect to the radiation axis of the acoustic vibration from the difference. The timer counter circuit 67 calculates the delay time of the reflected vibration with respect to the radiated vibration from the input carrier wave signal and the reflected wave detected by the frequency detector 63. Since the output of the carrier signal is constant, the position of the listener 1 can always be stably detected.

Further, by setting the frequency A and the frequency B detected by the measuring unit 2 to the frequency of the carrier signal and the frequency of the second harmonic of the carrier signal, respectively, it is possible to use two frequency detectors. This will be described with reference to FIG.
FIG. 4 is a block diagram illustrating a configuration of another example of the measuring unit 2.

Referring to FIG. 4, the frequency detector 71 includes:
The reflected vibration of the frequency A is detected, and the frequency detector 73 detects the reflected vibration of the frequency B. The carrier signal (frequency A) is input to the difference circuit 74, and the second harmonic (frequency B) of the carrier signal is input to the difference circuit 75 via the frequency divider 72.
Is entered. The following operation is the same as in the above example.
In this example, it is necessary to adjust the circuit so that the second harmonic is easily generated, but since the outputs of the two frequencies can be kept constant, the position of the listener 1 can be detected more stably. .

The frequency divider 72 can be arranged at the position shown in FIG.

Referring to FIG. 5, in addition to the configuration of the present apparatus described with reference to FIG. 1, a mixer 16 is provided between the amplitude modulator 13 and the amplifier 14, and a mixer 16 is provided between the high-frequency generator 12 and the mixer 16. A frequency divider 72 is provided. The frequency divider 72 to which the carrier signal has been input from the high frequency generator 12 divides the frequency of the carrier signal and outputs it to the mixer 16.

That is, by generating a reference signal in advance by the frequency divider 72 and adding it to the transmission wave, the same stable position detection can be performed without generating a second harmonic.

The control unit 3 causes the radiation direction adjuster 40 to change the direction of the apparatus based on the deviation of the acoustic vibration of the listener 1 with respect to the radiation axis calculated by the position calculator 30,
Instruct the listener 11 to emit acoustic vibrations. Further, based on the calculated distance to the listener 1, the amplifier 14
Is instructed to set the gain to an appropriate volume.

Next, the operation of this embodiment will be described. The position calculation device used in this description is the position calculation device shown in FIG. It is assumed that the frequency of the carrier signal output from the high frequency generator 12 is 40 KHz, the ultrasonic transducer is used for the electroacoustic transducer 15, and the operating voltage is 60V.

The audio signal output from the audio generator 11 and the 40 KHz carrier signal output from the high frequency generator 12 are amplitude-modulated by the amplitude modulator 13, and the electro-acoustic converter 15 is driven by the amplifier 14. 6 of possible voltage
The electro-acoustic transducer 15 is amplified to 0 V, converts the amplified amplitude-modulated signal into acoustic vibration, and radiates it into the air.

The acoustic vibration radiated into the air becomes a distorted wave due to the non-linear characteristics of the air, and is demodulated to the original audible sound while propagating through the air. This demodulated audible sound has the super directional characteristics of the original ultrasonic wave.

Now, the frequency detector 51 of the position calculating device 30
And 52 have a detection frequency of 30 KHz and a frequency detector 53
And 54 are set to 50 KHz. When the audio signal and the carrier signal are amplitude-modulated, they have symmetrical frequency components centered on the frequency of the carrier signal. Therefore, the sound signal before the amplitude modulation of the 30 KHz and 50 KHz acoustic vibration to be detected is 10 KHz. is there.

The frequency detectors 51 and 52 detect 30 KHz signals of the transmitted wave and the reflected wave, respectively, and
5 is used to calculate the reflectance. Similarly, the frequency detector 53
And 54 detect a signal of 50 KHz of the transmitted wave and the reflected wave, respectively, and calculate the reflectance by the difference circuit 56.

As for the vibration propagating in the air, the higher the frequency, the more the straightness increases, and the lower the frequency, the more the vibration spreads.
In the case of a low frequency, the diffused vibration is reflected even if the object is shifted from the radiation axis of the vibration. Utilizing this characteristic,
The deviation of the acoustic vibration of the listener 1 from the radiation axis is calculated from the reflectances of the two frequencies. Further, the timer counter 57 calculates the delay time of the reflected wave with respect to the transmitted wave from
The distance from the listener 1 is calculated.

Here, it is assumed that the listener 1 is shifted to the right with respect to the radiation axis. As the listener 1 shifts from the radiation axis, the reflectance obtained from the difference circuits 55 and 56 decreases. At this time, from the characteristic that the lower the frequency of the vibration is, the lower the reflectance obtained from the difference circuit 55 is,
The control unit can calculate the deviation from the radiation axis of the listener 1 with respect to the degree of decrease in the reflectance obtained from the difference circuit 56. In addition, if two of this apparatus are arranged horizontally, the listener 1
Can be calculated. That is, it is calculated that the listener has moved to the right.

The listener 1 calculated by the above method
The control unit 3 instructs the radiation direction adjuster 40 to point the apparatus toward the listener 1 based on the deviation from the radiation axis of the listener.
By arranging two apparatuses horizontally, the direction of the listener can be calculated, and the apparatus can be directed to the listener 1 by one operation.

Next, assume that the listener 1 has moved backward. Since the listener 1 is on the radiation axis, the difference circuits 55 and 5
Although the reflectivity obtained from 6 hardly changes, the time measured by the timer counter 57 increases because the distance from the apparatus increases.

The control unit calculates that the listener 1 has moved backward based on the time measured by the timer counter 57. Further, the distance to the listener 1 is calculated from the delay time, and the amplification factor of the amplifier 14 is changed so as to have an appropriate volume according to the distance.

[0040]

According to the present invention, since the speaker having high directivity is always directed to the listener and the volume is adjusted in accordance with the distance to the listener, the speaker is always optimal only for the listener even when the listener moves. There is an effect that the voice can be heard at an appropriate volume.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a position calculating device 30.

FIG. 3 is a block diagram showing a configuration of another example of the measuring unit 2.

FIG. 4 is a block diagram showing a configuration of another example of the measuring unit 2.

FIG. 5 is a block diagram showing positions where frequency dividers 72 are arranged.

FIG. 6 is a block diagram illustrating a configuration of a parametric speaker.

[Explanation of symbols]

1: listener 2: measuring unit 3: control unit 10: super-linear acoustic vibration emission circuit 11: sound generator 12: high-frequency generator 13: amplitude modulator 14: amplifier 15: electro-acoustic converter 16: mixer 20: Acoustic detector 30: Position calculation device 40: Radiation direction adjuster 51 to 54, 61 to 63, 71, 73: Frequency detector 55, 56, 58, 64, 65, 67, 74, 75, 7
7: Difference circuit 57, 66, 76: Timer counter 72, frequency divider

Claims (7)

[Claims] 1. An audio signal output means for outputting an audio signal, a high frequency output means for outputting a high frequency signal having a predetermined frequency, and an amplitude modulation signal for modulating the amplitude of the audio signal and the high frequency signal. Amplitude modulation means for outputting;
A parametric speaker comprising amplification means for amplifying the amplitude-modulated signal, and radiating means for radiating the amplified amplitude-modulated signal as ultrasonic acoustic vibration; and listening in front of the radiated acoustic vibration. Detecting means for detecting a reflected vibration reflected from a person or the like, a signal generated in the parametric speaker and the detected reflected vibration are input, and a signal generated in the parametric speaker and the reflected vibration Calculating means for calculating the deviation of the listener or the like from the radiation axis of the acoustic vibration; andinstruction means for directing the radiation direction of the acoustic vibration to the direction of the listener or the like based on the calculation result of the calculating means. An automatic azimuth determination speaker device, characterized in that: 2. The method according to claim 1, wherein the calculating unit detects energy amounts of predetermined first and second frequencies from the input reflected vibration and a signal generated in the parametric speaker. The speaker device according to claim 1, wherein 3. The calculating means comprises: first frequency detecting means for detecting an energy amount of the amplitude-modulated signal having a first frequency; and an energy amount of the amplitude-modulated signal having a second frequency. A second frequency detecting means for detecting, a third frequency detecting means for detecting an energy amount of the reflected vibration having the first frequency,
A fourth frequency detecting means for detecting an energy amount of the reflected vibration having the second frequency; and a difference between the energy amounts detected by the first frequency detecting means and the third frequency detecting means. A first circuit for obtaining a first reflectance from the difference, a difference between energy amounts detected by the second frequency detecting means and the fourth frequency detecting means, and a second circuit for obtaining a second reflectance from the difference. A second circuit for calculating a reflectance, a third circuit for calculating a difference between the first reflectance and the second reflectance, and calculating a shift of the listener or the like with respect to a radiation axis of the acoustic vibration from the difference; The speaker according to claim 1, further comprising a circuit. 4. The calculating means comprises: first frequency detecting means for detecting an energy amount of the amplitude-modulated signal having a first frequency; and detecting an energy amount of the reflected vibration having the first frequency. A second frequency detecting means for detecting the energy of the reflected vibration having a second frequency; a third frequency detecting means for detecting an energy amount of the reflected vibration having a second frequency; A first circuit for obtaining a difference between the obtained energy amounts, and obtaining a first reflectance from the difference; an energy amount detected by the third frequency detecting means; and an energy amount of a high-frequency signal of the second frequency. And a second circuit for obtaining a second reflectance from the difference, obtaining a difference between the first reflectance and the second reflectance, and obtaining a radiation axis of the acoustic vibration from the difference. Of the above listeners Automatic orientation determined speaker apparatus according to claim 1, characterized in that a third circuit for obtaining a record. 5. The calculating means comprises: first frequency detecting means for detecting an energy amount of the reflected vibration having a first frequency; and a second frequency detecting means for detecting an energy amount of the reflected vibration having a second frequency. A difference between the amount of energy detected by the first frequency detecting unit and the amount of energy of the high-frequency signal of the first frequency, and a first reflectance is calculated from the difference. A circuit, and an energy amount detected by the second frequency detection means and the second frequency signal generated by using a frequency divider.
A second circuit for calculating a difference between the energy amount and a high-frequency signal having a frequency of
Calculating a difference between the first reflectance and the second reflectance;
3. The automatic azimuth deciding speaker device according to claim 1, further comprising: a third circuit for calculating a deviation of the listener or the like from the radiation axis of the acoustic vibration from the difference. 6. The calculating means further calculates a distance between the listener and the like and the calculating means, and the instructing means further instructs the amplifier to set an amplification factor corresponding to the distance. The speaker device according to claim 1, wherein 7. The calculating means includes: first frequency detecting means for detecting an energy amount of the amplitude-modulated signal having a first frequency; and an energy amount of the amplitude-modulated signal having a second frequency. A second frequency detecting means for detecting, a third frequency detecting means for detecting an energy amount of the reflected vibration having the first frequency,
A fourth frequency detecting means for detecting an energy amount of the reflected vibration having the second frequency; and a difference between the energy amounts detected by the first frequency detecting means and the third frequency detecting means. A first circuit for obtaining a first reflectance from the difference, a difference between energy amounts detected by the second frequency detecting means and the fourth frequency detecting means, and a second circuit for obtaining a second reflectance from the difference. A second circuit for calculating a reflectance, a third circuit for calculating a difference between the first reflectance and the second reflectance, and calculating a shift of the listener or the like with respect to a radiation axis of the acoustic vibration from the difference; 7. The circuit according to claim 6, further comprising: a circuit; and a means for obtaining a delay of the reflected vibration with respect to the emitted acoustic vibration, and calculating a distance between the listener or the like and the calculation means from the delay. Automatic orientation speaker system.