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JPS5983496

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DESCRIPTION JPS5983496
[0001]
(For use! ?? r) The present invention relates to a microphone device, and more particularly to a
microphone device that automatically searches for an i source position at one time and picks up
a target sound. (Prior Art) Conventionally, in order to pick up audible sound, it goes without
saying that a microphone is used. In order to capture a relatively distant point 5, a single
directional high sensitivity microphone or a gun type narrow directional microphone is used.
Also, apart from this, as a method for capturing a relatively distant sound as well, a device
composed of a concave reflector for sound collection and a unidirectional microphone installed
at the focal point is used. There is. Furthermore, apart from the above, there is an idea of using
the microphone (arrangement) arrangement 11 in order to eliminate, as much as possible, the
sound other than the target whistle. This is to arrange a plurality of microphones linearly or at a
constant interval on a two-dimensional surface, thereby obtaining sharp directivity and thereby
eliminating noise and the like as much as possible. In this case, in principle, the directivity
sharpness or directivity gain is increased by increasing the number of microbons. Therefore,
according to the concept of using the microphone array, the target sound and other noises are
distinguished to be collected! You will be able to (for example, record). However, in the
conventional microphone device using a microphone array, the sharper the directivity, the more
difficult it is to collect the target sound. This is because the microphone device using the
conventional microphone array does not have the function of automatically searching for and
tracking the sound source, and therefore, in the case where the sound source is moving in
particular, the target sound source is accurately searched. , Because it can not be tracked.
Therefore, conventionally, it has been desired for a microphone device using a microphone array
to be able to search for and track a sound source automatically while having sharp directivity as
a whole. (Objective) The present invention responds to the above-described needs, and an object
of the present invention is to provide a narrow directivity microphone using a microphone array
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that can automatically search for and track a sound source. To provide the device. (Summary) In
order to achieve the above object, according to the present invention, (1) microphones are
arranged at predetermined intervals, and a plurality of linear arrays intersecting with
predetermined microphones in the array are formed. A plurality of first microphones, and (2) a
plurality of first microphones provided behind the microphones forming the two linear arrays
and respectively delaying the outputs of the micropons according to delay time setting signals
inputted thereto; In the first delay circuit, the main axis of the directivity pattern obtained by the
delay circuit and (3) the microphones forming the respective linear arrays can be swept (swept or
tL) periodically in the direction of the Alll's linear array direction. A means for supplying a
predetermined delay time setting signal; (4) a first mixing circuit for mixing the outputs of the
first delay circuit; (5) the plurality of microboules And a plurality of second delay circuits for
delaying the outputs of the plurality of microphones respectively according to a delay time
setting signal input thereto, and (6) the first mixing circuit An output is used as an input, a sound
source position is detected, and a predetermined delay time is set in each of the second delay
circuits so that "waves from the sound source reaching the microphones of the previous memory
pattern match on the time axis A means for supplying a signal, and (7) a second mixing circuit
which receives each output of the second delay circuit and outputs a signal obtained by
synthesizing the outputs are provided.
Furthermore, in the present invention, in order to achieve the above object, (1) a plurality of
microphones in a known position it and (2) at least three microphones of the plurality of the tobe-earned microphones are provided. A sample-and-hold circuit for sampling and holding an
output signal of the microphone, and (3) A / D conversion provided at the subsequent stage of
each of the sample-and-hold circuit and converting the output of the sample-and-hold circuit into
a digital signal A circuit, (4) means for storing the digital signal obtained at the scheduled time as
data, and (5) each provided at a subsequent stage of the plurality of microphones, according to
the delay time setting signal inputted thereto A plurality of delay circuits for delaying the outputs
of the plurality of microphones respectively for a predetermined time, and (6) Means for
supplying a predetermined delay time setting signal to each of the i11 small delay circuits so that
sound waves from sound sources arriving at the plurality of microphones coincide on the time
axis based on the stored data; (7) Each output of the delay circuit is used as an input, and a
mixing circuit for outputting a signal obtained by combining the outputs is provided. First, the
method of sound source search according to the first embodiment of the present invention
described below will be described with reference to the drawings. FIG. 1 is a directivity
characteristic diagram showing an example of a directivity pattern formed by microphones
linearly arranged (linear arrangement). In a plane (here, a plane corresponding to a sheet of
paper) including a linear array I formed by an array of a plurality of (five in this case)
microphones, directivity patterns superimposed by the plurality of microphones are, for example,
It is sharp like B of FIG. On the other hand, in the plane perpendicular to the linear arrangement
(here, r (plane) perpendicular to the paper surface), a directivity pattern almost the same as-
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microbons can be obtained. That is, this directivity pattern is generally broad. In the same figure,
b is the main axis of the directivity pattern B. Also, in general, when d / ? (d is a microbon
interval and ? is a sound wave wavelength) is less than 1, the side lobes of the directivity pattern
become smaller and become nearly unidirectional. Next, the output signal path K of each microbon forming the linear array I and a delay circuit are provided, and the delay time with respect to
the output signal is changed at a predetermined ratio for each of the microphones. The image of
the arranger is, for example, as shown by straight lines 3 and 4 indicated by broken lines in FIG.
That is, the image of the linear array I can be changed as the straight lines 3 and 4. Such a
change is, for example, in the case of the straight line 3, according to the distance between the
microphone with the delay time difference O (microbon at the left end of the drawing) and each
microphone other than the microphone with the maximum delay time difference (microphone at
the right end of the drawing). This can be done by proportionally allocating the maximum value
of the delay time difference. The same applies to the Ia line 4. Also, when the same-sensic delay
time is given to each microphone, the image of the linear array 2 is as shown by the straight line
2. Therefore, what can be said from the above description is that the directivity patterns obtained
by the microphones forming the lu wiring arrangement 11 are obtained by continuously
changing the delay time of the output signal of each microphone at a predetermined ratio. , A- +
B- + C or C-base ?? A in FIG. That is, the principal axis of directivity can be changed as a- + 1)
.fwdarw.C or C.fwdarw.b.fwdarw.a, and sweeping can be performed on a plane including the
linear arrangement. By the way, supposing that the principal axis of directivity swings up to 60
░ at the left and right respectively by the change of the image of the linear array of microbons
as described above, between microphones (however, the microphone distance d is 30?). The
maximum delay time difference is 6.1 ms. By the way, when the sound source S1 is, for example,
at the position of ? in FIG. 1, when the main axes of directivity are c K f and f by the sweep, the
output signals of the microphones forming the linear array I The amplitude is at a maximum
value. Therefore, if the delay time of each microphone is fixed to a value that can be formed by
the main axis C, it is possible to mainly pick up only the sound wave emitted from the sound
source S1 and eliminate other noises and the like. Next, the sweeping force ? of the main axis of
the directivity pattern is further crystallized and brightened using FIG. In the same figure, ?
indicates a linear array formed on the ceiling of the room, for example, by the microphones M1
to M5, and J indicates the microphones ml, m2, M3. 1 shows a wired inter-row formed by m4 +
m5. Further, 2 indicates a line of an axis extending vertically downward from the intersection of
the linear arrays I and J (here, the microphone M3). As described above, the directivity pattern
obtained by the linearly arranged microphones is, for example, first, taking the linear
arrangement I as an example, if the surface (1-Z ?) lcg that holds the linear arrangement I, It is
sharp.
Also, in a plane <I?J (?, J?Zt ?) perpendicular to the IM line arrangement (1), it becomes
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broad (a fan-shaped pattern). The sound source position obtained by sweeping the linear array I
direction of the 11t1 fan-shaped patterns is one-dimensional position information. In order to
obtain two-dimensional sound source position information, after obtaining the one-dimensional
position information, the microphone m 1 + m 2 r M 3 + m 4 r m 5 forming the linear array J It is
necessary to obtain a sharp directivity pattern D and sweep its major axis d in the direction of the
linear array J. That is, the exact position of the sound source can only be known by the two-step
sweep described above. As is apparent from the explanation of FIG. 1, it is the delay time of the
delay circuit that controls the direction of the main axis of directivity. From the viewpoint of the
delay time, the two-dimensional sound source position information includes the delay time
setting of each microphone forming the linear arrangement II I and the delay time setting of each
microphone forming the linear array J. It can be obtained by repeating alternately. Here, the
operation principle of the first embodiment of the present invention described below, including
the above-described method of picking up sound sources, will be summarized. (1) A microphone
array is used to pick up a target sound source. (2) The output signals of the individual
microphones are divided into two paths, and an output signal of the first path is delayed with N
delay time being cyclically changed, so that the main directivity is 4 f from the entire microphone
array 4! ll change. That is, as described above, f (narrowing is performed to search for the order j
# of the sound source. (3) When the position of the f source is determined, a predetermined
delay is given to the output signal of the second path based on that, so that the principal axis of
directivity of the entire microphone is directed to the direction of the sound source. Hereinafter,
FIG. 3 shows the main part of the first embodiment of the microphone device of the present
invention, and in particular, the position search of the sound source will be specifically described.
In FIG. 3, the signal output from the microphone 1 is amplified by the microphone amplifier 5
and delayed by the first delay circuit 8 composed of, for example, a BBD element. The delay
circuit 8 is for sweeping the main axis of the directivity pattern as described above for the
purpose of searching for the position of the sound source. As described above, the delay time of
the delay circuit 8 is determined by proportionally distributing the maximum value of the delay
time difference in accordance with the distance between the microphone with the delay time
difference of 0 and the microphone 1. That is, by the command signal from the microcomputer
(cp) t 5 set in advance so that the sound source position can be searched by the principal axis
sweeping of the directivity obtained by each of the microphones forming the linear array
including the microphone 1 It is determined by the frequency of the rectangular wave signal
(delay time setting signal) supplied via the Ilo port 16.
The rectangular wave signal is supplied to the delay circuit 8 via the path 13. Further, the delay
time of each delay circuit provided corresponding to each of the other microphones forming a
linear array including the microphone 1 is set in the same manner. Further, the delay time of
each delay circuit provided corresponding to each microphone forming a linear array orthogonal
to the 1?? line row described later is similarly set. Next, the output signal of the first delay
circuit 8 is supplied to the first mixing circuit 1 ░ together with the output signals of the other
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microphone circuit systems in the linear arrangement including the All microphones 1.
Therefore, according to the sweeping of the main axis of the directivity pattern, the mixing circuit
1o outputs an analog signal whose amplitude changes according to the strength of the sound,
that is, the angle between the sound source and the main axis of directivity. Become. In addition,
it is necessary to carry out the sweeping at a speed faster than the change of the sound source
position. Next, this analog signal is input to an A / I) converter (circuit) 19 through a band pass
filter 11 having a band of 500 flz to 11 cHz (which corresponds to approximately the center
band of the audio signal). , Is converted to a digital signal. This digital signal is input to C 915 via
Ilo port 1-18, where the sound source position H in the linear arrangement direction including
the microphone 1 is detected. By the way, as described above, in order to obtain each directivity
pattern necessary for sweeping the scheduled direction, a set of command signals (digital signals)
corresponding to the rectangular wave signal supplied to each delay circuit in advance is
previously A plurality of sets (for example, 1 to 100) are set. Therefore, the detection of the
sound source position according to C115 is performed by using the digital signal (this is referred
to as data number l) which corresponds to the one having the largest amplitude among the
plurality of analog signals obtained for each set of the command signals. , I is performed by
detecting one of 1 to 100). By the way, although the above-mentioned eyebrows and lights were
about main axis sweeping of the directivity pattern in the direction of a linear array (here, this is
referred to as the linear array 1 described above) including the microphone 1, a two-dimensional
f source In order to obtain the position 1M information, as described above, the directivity
pattern QJ gI in the direction of the wired array (here, referred to as the linear array J described
above) is orthogonal to the west 1] IH line array II. It is necessary to carry out an axis 1 check in
the same manner as the main scanning of the directivity pattern in the linear array 1 direction. A
divisor signal (data number) corresponding to the position of the sound source in the direction of
the linear array J, the analog signal of 4s to 15 mantissas with the main axis Rh M of the
directivity pattern of the latter j, where j is one of 1 to 100) can be detected.
Therefore, the accurate position of the sound source can be known by the data numbers i and j
detected as described above. Next, in FIG. 3, the output signal of the microphone amplifier 5 is
supplied to the path 6 and then to the second delay circuit 9 consisting of a B B D element as in
the first delay circuit 8. There is. The delay circuit 9 is for directing the main axis of directivity of
the microphone 1 in the direction of the position of the sound source based on the position
information of the sound source determined by the main scanning of the directivity pattern
described above. By the way, the delay time of the delay circuit 9 is supplied to the second delay
circuit 9 through the route 12 via the Ilo boat 17 by the command signal obtained as the
calculation result of C15 as described later. It depends on the frequency of the rectangular wave
signal being The Ilo port 17 is supplied to each of the microphones constituting the microphone
device and a delay circuit (a delay circuit equivalent to the second delay circuit 9) provided at the
subsequent stage of the microphone amplifier connected thereto. A rectangular wave signal
(delay time setting signal) is output. The frequency of the rectangular wave signal is a value such
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that the principal axis of directivity obtained from the entire microphone constituting the
microphone device is directed toward the sound source based on the above-described search
result of the sound source. Incidentally, the path 14 is for supplying the output signal of the
second delay circuit 9 to the second mixing circuit, as is apparent from i 51 ffl described later.
Next, a method of calculating and calculating the frequency of the rectangular wave signal that
causes the main axis of the directivity of the entire microphone to be directed in the direction of
the position of the sound source will be described with reference to the drawings. FIG. 4 is a
microphone array diagram showing an example in which 17 microphones are arrayed on a twodimensional surface. For example, assuming that the position of the sound source SI is (++ j + 2
░) and the positions of the individual microphones are (i ? + j ? ? + 0), the distance Li?j ?
between the microphone and fi is expressed by equation (1). Here, 1 corresponds to the data No.
1 (i = 1. 2......... M) obtained by main axis sweeping of the directivity pattern in the linear array 1
direction. 1 and j correspond to the data number j (j = 1.2.... M) obtained by sweeping the
directivity pattern in the direction of the IK line alignment force. It is j that is doing. Further, Zo
indicates the distance from the microphone array surface, that is, the I-J surface to the sound
source. Also, assuming that the maximum value of the distances I and il jl between the individual
microphones and the sound source is Lmax, the propagation time difference T I l jl between the
microphone of L max and the other microphones is expressed by equation (2) .
Ti'j '-(Lrnax-Li'j') / 340.0 (S)----(2) If this propagation time difference Ti'j 'is derived, to each
second delay circuit The frequency of the supplied square wave signal is generally expressed by
equation (3). fl + j I = ty / 'r 11 j l + l) ииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииии It is a
common probe that is determined for each microphone device that has been That is, as described
above, the cycles ? I / Ir 9 of the rectangular wave signal supplied to the second delay circuits
on the sides. Can be determined. Next, the first 'if of the microphone device of the present
invention, an embodiment of the present invention will be shown in the flow side diagram, and
this will be described and described 3, and in the figure, the same parts as in FIG. The parts are
indicated by the same reference numerals. Reference numerals 24 and 25 denote first and
second delay circuit blocks in which first and second delay circuits (corresponding to the delay
circuit 8.degree. In FIG. 3) crotched to each microphone system 11 are grouped as a block It is.
As described above, the first delay circuit block 24 performs main scanning of the directivity
pattern in order to search for a sound source. The rectangular wave (No. 8 is supplied via the Ilo
port 16 in response to the c, 15 command signal as described above, which is supplied to each
delay circuit constituting the delay circuit block 24. It is clear from the above-mentioned
explanation and the fact that the frequency of this rectangular wave signal is different for each
microbon system and is temporally changing. The second delay circuit block 25 is for directing
the main axis of the directivity pattern of the entire microbon in the direction of the sound
source. The rectangular wave signal for setting the delay time of each delay circuit constituting
the delay circuit block 25 is supplied from the Ilo port 17 in accordance with the command
signal derived operationally as described in FIG. 4 by C15. Ru. The frequency of the rectangular
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wave signal g is different for each microphone system, but is constant in time if there is no
change in the position of the sound source. The respective output numbers of the microbonbased delay circuits of the second delay circuit block 25 are supplied to the second mixing circuit
20 where they are mixed. An output of the mixing circuit 20 is supplied to the speaker system 23
through a band pass filter 21 having a 200 H 7 to 5 k I (z band (corresponding to a frequency of
f) and a broadband amplifier 22. .
As a result, the speaker system 23 outputs a sound. Next, the order of input / output of signals in
C115 and calculation will be described using the flowchart of FIG. When the source of the
microphone device shown in FIG. 5 is turned on and the calculation starts at Cp15, first, in step
S1, as described above, with the principal axis of directivity obtained by each microphone
forming the linear array ?. , 1111 sweeping in the direction of the small bundle of straight lines,
the command signal is output. In step S2, data obtained by sweeping the IH line array I according
to the command 1 word is manually input. Next, in step S3, as described above, with the
directivity main axis obtained by each of the microphones forming the linear array J, a command
signal for performing sweeping in the linear array J direction is output. In step S4, data obtained
by sweeping the linear array J in accordance with the command signal is input. Next, in step S5,
the maximum value of the data obtained by sweeping the 1a line array 1 and the J direction
(corresponding to the maximum one of the plurality of analog signals described above) is equal
to or greater than the predetermined value. If it does not reach the predetermined value, it is
determined that there is no sound source, and the process returns to step S1. If the
predetermined value is reached, the process proceeds to step S6. In step S6, the position of the
sound source is determined from the maximum value of the data obtained by sweeping the
curvilinear linear arrays I and J directions (specifically, the data numbers i and j described for
611). At step S7, the it fi of the equations (1) to (3) described above is line ?S. In step S8, III'I in
step S7. Based on the result, a command signal for directing the main axis of the directivity of the
entire microphone toward the sound source is output. After that, the process returns to step S1
again. By the way, based on the result of # 1 calculation in step S7, when a command signal to
direct the main axis of directivity of the entire microbon to the sound source direction is
outputted in step S8, new calculation is performed in step S7 The output does not change unless
a result is obtained. In the embodiment of FIG. 5 (the first embodiment), according to the
experimental results of the inventor, after the flowchart of FIG. 6 is started, step S17 j is
performed, and step S8 is performed again to return to step S1. Up to about 0.2 seconds. Further,
in this first embodiment, the main axis of directivity of the microphones forming linear arrays
orthogonal to each other is swept to search for the position of the sound source. Of course it is
possible to search for the position.
Further, in this first embodiment, although the frequency determination of the rectangular wave
signal for directing the principal axis of the directivity of the entire microphone toward the sound
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source is performed by the microcomputer, it is not limited to the microcomputer. It can also be
performed by other circuit systems. Next, another embodiment (second embodiment) of the
microphone device of the present invention is shown in FIG. 7 and this will be described. In the
figure, A1 to A5 are microphones linearly arranged, 31a to 35a are sample / hold amplifiers (S /
HT amplifiers), 31b to 85b are A / D conversion circuits, 31c to 35c are BBDs or CCD delay
circuits. , 42.43 is an I10 port, 44 is a C2, 45 a mixing circuit, 46 is an output terminal, and 47 is
a memory. In FIG. 7, the outputs of the microphones A1 to A5 are sampled and held in S / H
amplifiers 31a to 35a and then converted to digital signals by A / D conversion circuits 31b to
35b. This digital signal is stored as data in memory 47 via Ilo port 42 and C244. The above
operation is continued for a preset time (data increase time) tc. Next, using the data, in C144, the
cross-correlation function Cij is calculated according to equation (4). C1 j (?) ? ? P, 1 (t 1) О 1
g (10 ?) / N (4) where, E4 Is the output value of one of the microphones A1 to A5, Ej is the
output value of one of the microphones A1 to A5 j (l to j), and ? is the separation time (lag). N is
the number of data. As shown in FIG. 8, the cross-correlation function C1j has a maximum value
for the lag ? at just jt. Here, T and l indicate that the sound wave from the sound source arrives
at time ti at the microphone i and at time t j at the microphone j, but the time difference between
them. The time difference Tjl indicates that the output of the microphone j lags behind the output
of the microphone 1 by Tji if it is positive, as is clear from the equation (5). Conversely, if the
time difference Tji is negative, it indicates that the output of the microphone i lags behind the
output of the microphone j by Tlj. Tjl = Tj Ti ........... (5) Therefore, each microphone A1 The time
difference T ij between the microphone i and the other microphones can be obtained from the
cross correlation function with reference to a suitable one of, for example, the microphone i, for
example.
Incidentally, in FIG. 7, when the time difference T8j with respect to each of the other
microphones is derived with the microphone A3 as a reference, it is assumed that, for example,
the Tgj (Tll + T82 + TB8 + TH4 + T11s) is 1j as shown in FIG. In order to direct the main axis of
directivity of the microphone array from the microphones A1 to A5 to the sound source
direction, precisely, the outputs of the microphones A1 to A5 are respectively transmitted
through the delay circuits to the time axis. You need to match on the top. At this time, among the
microphones A1 to A5, the reference is a microphone whose time difference TIj is a negative
maximum 4f. It is necessary to set the delay time to each microphone with reference to the time
difference T8 of the microphone A5 (ie, in the embodiment of FIG. 7, as apparent from FIG. 9).
Specifically, the absolute value (the length of the arrow) of Tss is added to each Ts, 4 (T8, + Ta2 +
T0n r T841 T1) to obtain TT5 ░ (Ts + 1) shown in FIG. '521 Tss + T54 +' 14B) can be set as the
delay time of the delay circuits 31c to 35c of the microphones A1 to A5. That is, the command
signal corresponding to each T5j shown in FIG. 10 is output from C244 to Ilo port 43. As
described above, in FIG. 7, since the delay circuits 31c to 35c are formed of BBDs or CCDs, the
delay time can be continuously varied according to the frequency of the rectangular wave signal
(delay time setting signal). That is, when the delay time f i of one of the delay circuits 31c to 35c
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is f i and the frequency of the rectangular wave signal is f i, the relationship between the two is
as shown in equation (6). ?, = to / f ииииииииииииииииииииииииии Where K is a proportional constant determined
for each delay circuit. Therefore, the Ilo port 43 outputs a rectangular wave signal of a frequency
corresponding to the command signal and at which each of the delay circuits 31c to 35c can
obtain a predetermined delay. In addition, it goes without saying that the frequency fl of the
rectangular wave signal set as described above does not change unless the sound source position
is moved, and as a result, the command signal power month B according to Cp44 is moved. . Also,
as is apparent from the il1 diagram, the frequency fl of the rectangular wave signal is the data
acquisition time t.
And it can change for every time tT which added calculation time tD in C944 mentioned above.
In FIG. 7, the outputs of the microphones A1 to A5 are respectively delayed for a predetermined
time in the delay circuits 31c to 35c and supplied to the mixing circuit 45, as described above.
Therefore, at the output terminal 46, the outputs of the microphones A1 to A5 completely
coincide on the time axis, and a superimposed signal is obtained. Next, the main nine operations
in the embodiment of FIG. 7 will be further explained and described using the flowchart of FIG. In
FIG. 7, when an audio signal is output from each of the microphones A1 to A5, in step S1, the
output is sampled and held in the S /) I amplifier 31a to 35a. Next, in step S2, the outputs of the
S / H amplifiers 31a to 35a are converted into digital signals in the A / D conversion circuits 31b
to 35b. At step S3, the digital signal is stored as data in the memory 47 via the I10 boat 42 and
Cp44. Next, in step S4, it is determined whether or not the maximum value of the data stored in
the memory 47 in step S3 is equal to or greater than the planned value. If the planned value is
not reached, the process returns to step S1 as no sound source. . If the predetermined value is
reached, the process proceeds to step S5. In step S5, based on the data in step S3, a command
signal is output at Cp 44 with the following calculation 12. (1) First, the cross correlation
functions C, ..., (T) of the microphone i of the microphones A1 to A5 and the microphone j of the
song are calculated by the equation (4). (2) From the calculation result of the cross-correlation
function, the time difference Tlj of each of the reference microphone 1 and the other micro-bons
j is derived. (3) Next, by adding the absolute value of the negative maximum value of the time a T
1j to each 'l' 1j, the command signal corresponding to the required delay time of each
microphone can be Output to In step S6, in the I10 boat 43, the frequency of the rectangular
wave signal to be output to each of the delay circuits 3 c to 35 c is set and output from the
command signal and the equation (6). The main operation of the embodiment shown in FIG. 7 is
as described above. However, when the steps 81 to S6 described in I) 11 are completed, the
process returns to step S1 again to repeat the same operation.
In the embodiment of FIG. 7, five microphones are used, but in a microphone device using a
microphone array, as is generally well known, any number of three or more microphones may be
used. Also, the arrangement may be arbitrary. Further, the setting of the delay time to each
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microphone may be calculated by the position of each microphone and the time difference
between any three microphones. In this way, even if there are three or more microphones, three
S / H amplifiers and three A / D conversion circuits are sufficient. (Effects) As apparent from the
above description, according to the present invention, in a narrow directivity microphone
apparatus using a microphone array, there is an effect that a sound source can be automatically
searched for and tracked. Therefore, in a small hall, a conference hall or the like, if the
microphone device of the present invention is used, different utterances of the speaker can be
collected one after another, and noises other than the sound source can be eliminated.
[0002]
Brief description of the drawings
[0003]
FIG. 1 is a directivity characteristic diagram showing an example of a directivity pattern formed
by linearly arranged microphones, and FIG. 2 is an orthogonal microphone array diagram for
explaining a method of main scanning of the directivity pattern, 3 FIG. 4 is a block diagram
showing the main part of the first embodiment of the microphone device of the present
invention, FIG. 4 is a microphone array diagram showing an example in which the microphones
are arranged on a two-dimensional surface, and FIG. 5 is a microphone device of the present
invention FIG. 6 is a block diagram showing a first embodiment of the present invention, FIG. 6 is
a flow chart for explaining the j sequence of input / output and operation of No. 16 in C 215 of
FIG. 5, and FIG. FIG. 8 is a block diagram showing a second embodiment of the microphone
device, FIG. 8 is a characteristic diagram showing the relationship between the cross correlation
function and the lag ?, and FIG. 9 is a diagram for clarifying the 1tjl difference between
microphones , Figure 1O Diagram for explaining the delay time set in each delay circuit, FIG. 11
data acquisition time t.
12 is a flowchart for explaining the operation of FIG. 7, and FIG. 12 is a flowchart for explaining
the operation of FIG. 7. is there. 1, A1 to A5: microphones 8, 9, ... first and second delay circuits
10. . 20 ... first and second mixing circuit, 15.44 ... microcomputer, 16 to 18 42, 43 ... rlo hart,
19, 31 b to 35 b-A / D conversion circuit, 24 .25 иии 1st and 2nd -i 'extended circuit block, 31a to
35a иии ? non pull bold amplifier, 31 cm 35 c и и и Delay circuit Person-607-n) Figure 5 Figure 6
Figure 7 Figure 8-Tii OTji Figure 9 Figure 1 0 Figure 0 +-0 + Figure 11 The frequency f of the his
signal. ????????????
03-05-2019
10
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