JPH02265398

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DESCRIPTION JPH02265398
[0001]
Industrial Application Field The present invention relates to a directivity variable sound source
capable of changing directivity. [Prior Art] Conventionally, when it is desired to transmit
information to a person in a specific area, a horn is attached to the speaker to make the
directivity sharp or use a parametric speaker having a sharp directivity. 0 For example, a speaker
with a horn (for example, a trumpet speaker) as a directional sound source that generates a
product description of a product exhibition, a voice such as a guide broadcast in a station yard, a
crossing, an alarm sound at a pedestrian crossing There has been a system in which information
is transmitted only to a specific area by using a parametric speaker having extremely sharp
directivity, and noise pollution to the vicinity is prevented. [Problems to be Solved by the
Invention] However, the trumpet speaker with a horn has a problem that the shape becomes
large, and the directivity can not be made sharp too much, and it is unsuitable when transmitting
information to a narrow area Was a problem. On the other hand, even though general parametric
speakers have much sharp directivity, they can not change the directivity, so if it is necessary to
emit sound in different directions, install the parametric speakers freely, Although the direction
of the parametric speaker is changed as needed to emit sound in a predetermined direction, there
is a problem that a swing mechanism for mechanically changing directivity is complicated. The
present invention has been made in view of the above points, and the object of the present
invention is to make it possible to emit voice in a predetermined direction by electrically
changing directivity, and to be simple in structure and small in size. It is in providing a sex
variable sound source. [Means for Solving the Problems] The variable directivity sound source
according to the present invention comprises a group of transducers in which a plurality of
transducers are arranged in a matrix on the same plane and transducers in each row are
connected in parallel, and a carrier high frequency An oscillator that generates, a phase adjuster
that adjusts the phase of carrier high frequency to form carrier high frequency corresponding to
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each transducer row, and AM that AM-modulates the carrier high frequency output from each
phase adjuster with an audio signal It consists of a modulator and an amplifier that amplifies the
modulation signal output from each AM modulator and applies it to each transducer row, and
causes two types of ultrasonic waves generated from each S-motor to interfere in air In addition
to reproducing the voice, the phase controller controls the phase adjustment of the carrier high
frequency wave by the phase adjuster to change the direction of the voice emitted from the
vibrator group. The present invention is configured as described above, in which a plurality of
transducers are arranged in the form of a matrix on the same plane, and the transducers of each
row are connected in parallel, and the carrier high frequency generated by the oscillator is
obtained. The phase is adjusted by a phase adjuster to form a carrier high frequency
corresponding to each transducer row, and the carrier high frequency output from each phase
adjuster is AM-modulated with an audio signal and amplified to be each transducer row To
reproduce the voice using the principle of parametric speaker, and control the phase adjustment
of the carrier high frequency by the phase adjuster with the phase controller to change the
direction of the voice emitted from the vibrator group Therefore, the directivity can be
electrically changed to transmit information in a predetermined direction, and a compact
directional variable sound source having a simple configuration and small size can be provided.
FIG. 1 shows an embodiment of the present invention, wherein a plurality of transducers 10, 1
□, 1.. Are arranged in the form of a matrix in the same plane, and each row of transducers 11+ i
+. lx ... 13.1. ... And the vibrator group l connected in parallel, and the carrier high frequency f. ,
And phase adjusters 33, 3 □, 3... Which adjust the phase of the carrier high frequency to form
carrier high frequency foz foz + fos corresponding to each transducer array 11 ′, 12 ′ 1 ′.
And each phase adjuster 37, 3 □, 3. Of the carrier high frequency f0. . AM modulators 60, 6 and
6 for AM-modulating I 02 + f 03 with the audio signal fs, and modulation signals fm, fm2. 7. An
amplifier for amplifying fms and applying it to each transducer array 1+ ', 1z13'. . 72, 7. And
each oscillator I11 12. The two ultrasonic waves (upper and lower side band waves of AM
modulation wave) generated from Ij are made to interfere in the air to reproduce the sound, and
the phase adjustment is performed by the phase adjustment volume VR of the phase controller 4.
3I, 3 □, 3. By controlling the phase adjustment of the carrier high frequency fez foz + fos
according to the above, the direction of the sound emitted from the transducer group 1 is
changed. In the figure, reference numeral 5 denotes an audio signal generator for generating an
audio signal fs, and reference numeral 8 denotes a sound JIN adjustment volume for adjusting
the amplification degree of the amplifiers 71, 72 °, l. The operation of the embodiment will be
described below. FIG. 2 shows the principle of operation of a parametric speaker using non-linear
interaction (non-linear parametric action) of sound waves in air, and now two sound waves fl and
f2 slightly different in frequency are shown in FIG. As shown in a), the two sound waves f + and
fz are radiated in the air as shown in FIG. 2 (b), and the sum frequency and the difference
frequency are caused to interfere with each other in the air (utilizing air non-linearity) The sound
waves f + + f 2 and f + f 2 are generated, and here two air waves f and f 2 are ultrasonic waves,
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and the difference frequency f + fz is an audible sound so that air can be generated. The audible
sound generated inside can be sent to a specific area with sharp directivity. By the way, in the
embodiment, a modulated wave fm obtained by amplitude-modulating the carrier high frequency
f 01 r f 02 + foj with an audio signal (audible sound signal) fs, fm 2. As shown in FIG. 2 (e), the
modulated waves fm + + f m z and f m s are driven by the upper side band wave and the lower
side, respectively. A sideband wave is provided, and two kinds of ultrasonic waves (f +, f2)
respectively generated corresponding to the upper and lower sideband waves are emitted into
the air, and the difference is caused by the non-linear interaction of the subject sound wave in
the air. An audible sound of frequency (f + fz), ie the sound corresponding to the original speech
signal fs, is reproduced.
Here, in the embodiment, by adjusting each of the phase adjustment volumes VR, VR2 of the
phase controller 4, the vibrator 11.12. The phase of the ultrasonic wave emitted from Is can be
made different appropriately to change the area in which the sound corresponding to the audio
signal fS is reproduced, and the directivity can be electrically changed to emit the sound in a
predetermined direction. I have to. In addition, since it is not necessary to provide a horn and it is
not necessary to provide a swing a, it is possible to obtain a compact directional variable sound
source having a simple configuration. FIG. 3 shows an application example using the directivity
variable sound source of the present invention for a wake-up, in which the directivity variable
sound source X is disposed on the ceiling and in the direction of the person YA, Y who sleeps
next to them. Directionality can be appropriately directed, and alarm sounds can be delayed only
to predetermined persons Ya and Ya at different alarm times. Now, the directivity setting by the
phase adjustment volume VR is in the A direction, and the directivity setting by the phase
adjustment volume VR2 is in the B direction, and at the alarm time of the person YA, the phase
adjustment volume VR. The ultrasonic wave of the phase set in is generated from the transducer
11.12 ° 1 and alarm sound is generated only in six directions, and the alarm time of the person
Yll is set by the phase adjustment volume ■ R2. A moving ultrasonic wave is generated from the
transducers 18.1 □ and 13 to generate an alarm sound only in the B direction. Therefore, unique
wake-up can be performed without raising the next person YA, Y at a predetermined wake-up
time. Also, by forming the phase controller 4 so as to swing the directivity in the range of ± 30
° in the horizontal direction at a speed of 20 Hz, it is possible to realize a fan-shaped flat
directivity, and such a directivity variable sound source Can be used to generate the siren sound
of an emergency vehicle, noise pollution due to the siren sound leaking in the vertical direction
can be prevented. That is, although it is sufficient that the siren sound of the emergency vehicle
be kept in the vicinity of the road surface ahead in the traveling direction, the noise pollution is
caused by the reflection of buildings leaking in the vertical direction, If the directional variable
sound source is used to generate the siren of an emergency vehicle, the noise due to the siren
sound in the area where the buildings are lined is significantly reduced, which helps to prevent
the noise. The present invention is configured as described above, in which a plurality of
transducers are arranged in the form of a matrix on the same plane, and the transducers of each
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row are connected in parallel, and the carrier high frequency generated by the oscillators The
phase of the carrier is adjusted by the phase adjuster to form carrier high frequency
corresponding to each transducer row, and the carrier high frequency output from each phase
adjuster is AM-modulated with an audio signal and amplified for amplification. It applies to the
column and reproduces the voice using the principle of parametric speaker, and controls the
phase adjustment of the carrier high frequency by the phase adjuster with the phase controller to
change the direction of the voice emitted from the vibrator group As a result, the directivity can
be electrically changed to emit a voice in a predetermined direction, and in addition, the
configuration can be simplified, and a compact directional variable sound source can be
provided.
[0002]
Brief description of the drawings
[0003]
FIG. 1 is a schematic block diagram of an embodiment of the present invention, and FIGS. 2 and 3
are operation explanatory views of the same.
1 is a transducer group, it is 12.13 is a transducer, 1.degree. "Is a transducer array, 2 is an
oscillator, 3I, 32.degree. 3, a phase adjuster, 4 is a phase controller, 62.degree. 63 is an AM
modulator, 71 + 72.degree. 7, an amplifier.
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