JPS6154793A - Variable directivity microphone - Google Patents

Abstract

PURPOSE:To make directivity characteristics change widely and narrowly by using a microphone array having sharp directivity characteristics, setting a central layout area, the first side layout area and the second side layout area and combining an output from a microphone unit belonging. CONSTITUTION:The microphone consists of a central layout area ZC composed of a layout of at least three microphone units of the central part, the first side layout area ZS1 composed of a layout of plural microphone units MUb1-MUbm which are set to one side of the central layout area ZC and the second side layout area ZS2 composed of a layout of plural microphone units MUc1-MUcm laid to the other side of the central layout area ZC. In plural microphone units MUa1-MUan, MUb1-Mubm and MUc1-MUcm composing a microphone array MA, prescribed weight is loaded to each sensitivity by respective coefficient devices Ka1-Kan, Kd1-kdn, Kb1-Kbm and Kc1-Kcm which are installed for respective microphone unit.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application! l'F) The present invention relates to a variable directional microphone, and particularly to a variable directional microphone that uses a microphone array and has variable directivity.

(Prior Art) Variable directional microphones have been known for a long time, but in conventional variable directional microphones, the directional characteristics of a single microphone can be varied narrowly and widely. Ta.

(The problem that R-mei is trying to solve) For this reason, in the conventional variable directional microphone, since sharp directional characteristics cannot be obtained in principle, the range in which the directional characteristics can be varied narrowly and widely is narrow. Ta.

On the other hand, as a microphone with sharp directional characteristics, a microphone array consisting of a plurality of microphone units arranged in a desired arrangement has been known for a long time, but in the case of directional microphones using microphone play, Conventionally, no means have been taken to make the directional characteristics variable in a narrow and wide range.

By the way, 1. For example, if a microphone array with sharp directional characteristics is used to collect sound during stage broadcasts, etc., it is possible to pick up sound clearly even from a distance without picking up much reverberation in the hall. In the above scenes where the performers were saying their lines at the same time, it was not possible to pick up the voices of all the performers with one microphone array.

In such cases, it is necessary to collect sound with multiple microphone arrays, but since microphone arrays with sharp directional characteristics have a large shape, multiple microphone arrays are used. In such a case, problems arise, for example, in that a large amount of space is required for operation, and that it interferes with the audience's enjoyment of the M-play.

In order to solve the above-mentioned problems, the applicant company first arranged variable directional microphones constituted by a variable directional microphone array, that is, a plurality of microphone units in a desired arrangement. In the microphone array, a central arrangement area of microphone units including at least one microphone unit at the center of the microphone array is set;

By arranging a plurality of microphone units arranged on one side of the central arrangement area of the microphone units described above, a first lateral arrangement area of the microphone units is set, and the other area of the central arrangement area of the microphone units is set. means for setting a second lateral array area of microphone units by arranging a plurality of microphone units arranged side by side;
Changing the ratio of the output signal obtained based on the microphone unit belonging to the central array area of the microphone unit and the output signal obtained based on the microphone unit belonging to the first and second side array areas of the microphone unit. a signal ratio changing means for changing the output signal obtained based on the microphone unit belonging to the central arrangement area of the above-mentioned microphone unit, and the output signal obtained based on the microphone unit belonging to the central arrangement area of the above-mentioned microphone unit; Weighting is applied to each microphone unit constituting the microphone array so that the directional characteristic obtained when the ratio of the output signal to the output signal obtained from the microphone unit is 1 becomes a predetermined directional characteristic. a variable directional microphone, and
In the variable directional microphone as described above, an output signal obtained based on the microphone unit belonging to the central arrangement area of the microphone unit, and a first output signal obtained by the microphone unit. means for keeping the output signal generated based on the distant sound source in front substantially constant even if the ratio to the output signal obtained based on the microphone unit belonging to the second side array area is changed; and a microphone unit belonging to the central arrangement area of the microphone units described above so that the directional characteristics of the microphone gradually become sharp from a broad state in the variable directional microphone as described above. The output obtained based on the output (No. 8) and the output obtained from the microphone unit (No. 1.
When the ratio to the output signal obtained based on the microphone unit belonging to the second side array area is changed, the output signal generated based on the distant sound source in front corresponds to the change in the signal ratio described above. We have proposed a variable directional microphone equipped with a means for gradually increasing the amount of radiation, and have achieved some results by implementing it.

However, the previously proposed variable directional microphone described above is based on the microphone unit belonging to the central array area of the aforementioned microphone unit, which is designed to be used no matter how the directional characteristics of the microphone array are adjusted. The obtained output signal and the first signal from the microphone unit described above. The directional characteristic obtained when the ratio to the output signal obtained based on the microphone unit belonging to the second side array area is 1 becomes a predetermined directional characteristic. Since the weighting of each microphone unit belonging to the above-mentioned central array area by the microphone unit is fixed, if the directivity of the microphone array is adjusted to be the broadest, that is, the above-mentioned central arrangement area by the microphone unit is When only the output signals of each microphone unit belonging to the array region zC are used, the directivity characteristic obtained for the high frequency signal has a disadvantage in that the level of side lobes becomes large.

(Means for Solving the Problems) The present invention relates to a microphone array in which a plurality of microphone units are arranged in a predetermined arrangement manner, and the present invention provides a microphone array including at least three microphone units in the center of the microphone array. A central array area of the microphone units is set, and a first lateral array area of the microphone units is set by arranging a plurality of microphone units arranged on one side of the central array area of the microphone units. , due to the arrangement of the plurality of microphone units arranged on the other side of the central arrangement area of the microphone unit, the second
and means for obtaining a first signal that is synthesized by applying predetermined weighting to the output signals from each microphone unit belonging to the central array area of the microphone units. In addition to the first signal described above, a second signal obtained by combining the output signals from each microphone unit belonging to the central array area of the microphone unit with predetermined weighting applied to each of the output signals is obtained. , the first one by the microphone unit. means for obtaining a fourth signal obtained by synthesizing output signals from microphone units belonging to the second side arrangement region with a third signal obtained by synthesizing the respective output signals with predetermined weighting applied thereto; , signal ratio changing means for changing the ratio of the first signal to the fourth signal, and a state in which only the first signal is used as an output signal from the directional microphone. In,
so that the directional microphone has a predetermined first directional characteristic.

The microphone array is formed such that the directional characteristic obtained when the ratio of the first signal to the fourth signal is 1 becomes a predetermined second directional characteristic. and means for weighting each microphone unit, and the variable directional microphone as described above, wherein the first signal and the fourth signal are The means for changing the level of the first signal and the fourth signal (No. In the variable directional microphone provided and the variable directional microphone as described above, the first signal described above and the first signal 4 is changed, the output signal generated based on the distant sound source in front is gradually increased, corresponding to the change in the signal ratio. The present invention provides a variable directional microphone provided with means for changing the signal level of the fourth signal.

(Example) Hereinafter, specific contents of the variable directional microphone of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the variable directional microphone of the present invention. In FIG.
MUan, ni Ubl~Mυbm, MUcl~Mυcm
A microphone array is constructed by arranging and arranging the microphones in a desired arrangement manner.

Each microphone unit MUalNMUan used to form the above-mentioned microphone array MAti-W,
As MUbl~MUbm, MUcl~Mυcm,
As with the configuration of a normal microphone unit, each has a predetermined unidirectional characteristic (e.g., cardioid,
A microphone with a hypercardioid (hypercardioid) is used.

In the microphone array HA formed by arranging the plurality of microphone units described above in a required arrangement manner, z
C is a central array area consisting of an array of n microphone units set to include at least three microphone units at the center of the microphone array HA, and ZSI is a central array area formed by the aforementioned microphone units. A plurality of (m) microphone units Mubl to MUb set on one side of the area ZC
252 is a first lateral arrangement area of microphone units having an arrangement of +a, and 252 is a plurality of (m) microphone units MUcl~ arranged on the other side of the central arrangement area zC of the microphone units.
This is a second lateral arrangement area of microphone units having an arrangement of MUcm.

Kal~nian, Kbl~Kbm, Kcl~Kcm,
di to Kdn assign unique weights to the sensitivities of each microphone unit forming the microphone array HA.

ADDc is a coefficient multiplier that performs
It is an adder that adds signals weighted by coefficients 1i1Kal to Kan to the output signal from Uan, and further,
ADDt is a signal obtained by weighting the output signals from the microphone units and υb1 to MUbm belonging to the first lateral arrangement region 251 described above with coefficients Kbl"Kbm, and the microphone unit belonging to the second lateral arrangement region 252 described above. A signal (third signal) obtained by weighting the output signals from υc1 to MυcI11 with coefficient units Kcl to Kc+w, and a coefficient unit Kd to one output No. 1 from the microphone unit MUal-MUam belonging to the central array area zC.
This is an adder that performs addition with a signal (second signal) weighted by dn from 1 to dn, and the output from this adder ADDt (i is the fourth signal).

Further, VRI is the output (1
(first signal), that is, a composite signal (first signal) obtained by adding signals weighted by coefficient units Kal to Kan to the output signals of all microphone units MUal to Mυan in the central array area zC. VH2 is the output signal (fourth signal) from the adder ADDt, that is, the microphone unit MUbl belonging to the first side array area ZSI. A coefficient multiplier K is applied to the output signal from ~Mυba+
A signal obtained by weighting bl~ with bm and a microphone unit MUc belonging to the second side array area 252 described above.
The output signal from l~MυcI11 is applied to the coefficient multiplier, and C1~ to C
1 weighted signal (third signal) and the microphone unit MUa 1 placed in the central array area ZC.
~Nira 2 signal that adjusts the signal level of the composite signal (fourth signal) obtained by adding the output signal from MUam and the signal weighted by d1 to Kdn in the coefficient unit (second signal) The first signal level adjuster VRI and the second signal level adjuster VH2, which are level adjusters, are configured to vary the ratio between the first signal and the fourth signal. As a result, the directional characteristics of the microphone are divided into the broadest state obtained when only the first signal is present and no fourth signal is present, and the broadest state obtained when only the first signal is present and the fourth signal is absent. The ratio to the fourth signal is variable between a case of 1 and a correspondingly sharpest state.

The first point mentioned above. Second signal level regulator VRI, VR2
The output signals of are added by an adder ADD and outputted to an output terminal O as an output signal of the variable directional microphone.

In the variable directional microphone of the present invention implanted as described above, a plurality of microphone units MUal to MUan forming the microphone array MA,
Ubl~MUbm, MUcl"MUcm are the individual coefficient multipliers, Kal~Kan, and di~Kdn provided for each individual microphone unit, as described above.
, Kbl~Kbm, and Kcl~KcPeng, predetermined weighting is applied to each sensitivity, and υal=MUan1MUb for the plurality of microphone units making up the microphone array h^ mentioned above.
The manner of weighting the individual sensitivities of 1 to MUbm and 001 to M0cm is as follows: First, the sharpest directivity required for the microphone, that is, the ratio of the first signal to the fourth signal is 1. The directional characteristics obtained when the first signal level adjuster VRI and the second signal level adjuster VR2 are adjusted so that Needless to say, this must be done.

Here, with reference to FIG. 1O and FIG. 11, when it is assumed that different am weighting is applied to each microphone unit in the microphone array, the above-mentioned weighting in different manners The following is an explanation of how the directivity characteristics obtained by the microphone array (particularly paying attention to the width of the main lobe and the size of the side lobes) changes.

Lines a, b, c, and d in FIG. 10 illustrate patterns of weighting to be applied to each microphone unit arranged in the microphone array.
In FIG. 10, the horizontal axis is the arrangement direction of the microphone units to be arranged in the microphone array, the vertical axis is the gain, and the weighting pattern shown by line a in FIG. 10 is rectangular (left tumbler). The weighting pattern shown by the window abt c is a Hamming window, and the weighting pattern shown by line d is a panning window.

In addition, (a) to (d) in FIG. 11 are for a microphone array in which a total of 41 microphone units are arranged so that the distance between adjacent microphone units is 28.3 mm. , shows the directional characteristics of the microphone array that should be obtained when weighting as shown by WIa - d in Fig. 10 is applied to each microphone unit in which the microphone array is implanted. Ori.

FIG. 11(a) shows the directional characteristics of the microphone array obtained when weighting is applied as shown by line a in FIG. 10 to each microphone unit in which the microphone array is implanted. Figure 11(b) shows the directional characteristics of the microphone array obtained when each microphone unit constituting the microphone array is weighted as shown by the lines in Figure 10. (C) in Figure 11 shows the directional characteristics of the microphone array obtained when each microphone unit constituting the microphone array is weighted as shown by line C in Figure 10. (d) in the figure shows the directivity characteristics of the microphone array obtained when weighting as shown by line d in Figure 1O is applied to each microphone unit making up the microphone array. There is.

That is, the weighting pattern shown by lines a-d in FIG. 10 and (,) to (d) 4 in FIG. 11:
Comparing the directional characteristics of the microphone array shown, for example, line a in FIG.
If the weighting of the rectangular window shown in Figure 1 is used, that is, if the output signals from all the microphone units making up the microphone array are combined with the same gain, the directivity obtained by the microphone array will be The characteristics are less favorable with a narrow main lobe but a large number of high level side lobes. Then, the weighting to be applied to each microphone unit constituting the microphone array is the 10th weighting.
It can be seen that the weighting as shown by @cyd in the figure, that is, the closer to the Hanning window, the lower the level of side lobes, which is preferable from a practical point of view, can be obtained.

Regarding the directivity of a microphone array, the overall length of the area where each microphone unit making up the microphone array is arranged is important, and the IIJ distance between each microphone unit is irrelevant to the directivity. 0 For example, as in the example above, the directional characteristics of a microphone array where the distance between each microphone is 28.311II and the total number of microphones is 41, and the distance between each microphone is 14.15m+*. The directional characteristics are the same as those of a microphone array with a total number of 81 microphones.

FIG. 2 shows that in the variable directional microphone of the present invention,
A plurality of microphone units MIJal~MUan, MUbl~ forming the microphone array MAt41
MUbm, MUcl"MUcm" This shows an example of weighting for the sensitivity of each of the MUcm, and in the example shown in FIG.
, MUbl to MUbm, MUcl" A curve connecting each point so that the weighting of the sensitivity of each MUcm becomes a so-called Hamming window is for each microphone belonging to the central array area zC of the microphone array HA in the variable directional microphone of the present invention. Unit NUal~Mva
A signal in which each output signal from n is weighted by a Hamming window with coefficients fiKal to Kan, that is, a mode of weighting applied to the first signal output from the adder ADDc is shown. It is also.

, @ −* l) −e shown in Fig. 2(b)
A curve connecting each point of C-+h-e i→j→e→f→g is a curve connecting each point of i→j→e→f→g.
Coefficient multiplier Kbl~Kbm is applied to the output signal from 1~14ubs.
The weighted signal and the second lateral array region 2 described above
Microphone units MUcl to MUc+ that correspond to 52
C! to the coefficient multiplier to the output signal from *! A signal (third signal) weighted by ˜Kcm and a signal (second signal) obtained by weighting the output signals from the microphone units MUal to NUam belonging to the central array area ZC by a coefficient 11Kdl−Kdn. The fourth value obtained by adding with adder ADDt
The figure shows the manner in which weighting is applied to the signals.

Then, the curve a-4b→c- in FIG. 2(b) described above
The manner of weighting applied to the fourth signal shown in 4h-41→j→0→f→g is shown in the above-mentioned fourth signal and in FIG. 2 (a) above. When adding the first signal weighted as follows on a one-to-one basis, the weighting aspect of the entire signal obtained by the addition is
In other words, the weighting of the Hamming window shown by the curve connecting the points a→b→C→d→6→f→g in (b) of FIG. From the figure surrounded by the curve connecting each point of a → 1) 4C → d → e → f → g in (b), (a
) is shown in one*n−*m! The curve in (b) of Figure 2, as obtained by subtracting the figure surrounded by the curve connecting each point of @ -+ l)→C-) )1-dp
i −) j → e → f −) g.

VRI is the output signal (first
signal), that is, a composite signal (first signal) obtained by adding signals weighted by coefficient units Kal to Kan to the output signals of all microphone units MUa 1 to MUan belonging to the central array area ZC. The first signal level gR adjustment VB2 for performing the level gilm is the output signal (fourth signal) from the adder ADDt described above, that is, the microphone units MUbl to Mυbm belonging to the first side array area 251. A coefficient multiplier Wb is applied to the output signal from
1 to Kbse and the microphone unit M[I belonging to the second side array area ZS2 described above.
Coefficient multipliers Kcl to Kc are applied to the output signals from c1 to MUc+a.
The signal weighted by +w (third signal) and the microphone unit MUal reaching the central array area ZC described above.
-Synthesis obtained by adding the output signal from MUam and the signal (second signal) weighted by the coefficient units Kdl to Kdn (
A second signal level adjuster that adjusts the signal level of No. 8 (fourth signal), the first signal level adjuster VRI and second signal level adjuster VR2 described above are An operation is performed in which the ratio between the first signal and the fourth signal is varied, so that the directional characteristics of the microphone are such that only the first signal is present and the fourth signal is completely absent. It is made variable between the broadest state obtained correspondingly and the sharpest state obtained corresponding to the case where the ratio of the first signal to the fourth signal is 1.

In the variable directional microphone of the present invention.

No matter when the directional characteristics are the sharpest or the broadest, the weighting applied to the microphone unit used at that time is the same. Therefore, the directivity characteristics (especially in the high range) in any of the above cases are made to be good.

Microphone array NAt - multiple microphone units MUal~Mυan, Mυb1~M
When a Hamming window as shown in Fig. 2 is adopted as a weighting mode for each sensitivity of υb■, MUcl to MUcm, the sharpest directivity characteristic can be obtained from the microphone. When it is done,
Since a directivity characteristic in which the main lobe does not spread much and the side lobes are small is obtained, the microphone array has At1- υal to MUan1 MUbl to MUbm to the plurality of microphone units constituting the microphone array.

It is a desirable implementation 1141 that a Hamming window as shown in FIG. 2 is employed as a weighting method for the sensitivity of each of Mud to MυC 111.

However, when the microphone is designed to obtain the sharpest directional characteristics, the side lobes may be slightly larger.

In cases where it is desired that only the main lobe be sharp, multiple microphone units NυalNMUan, M constituting the microphone array MA may be used.
As a mode of weighting the sensitivity of each of Ubl to MUbm and MUcl to MUcm, for example, weighting as illustrated in a of FIG. 1O is adopted.

As described above, the microphone array NAArt to be adopted in the configuration of the variable directional microphone of the present invention
Multi-AM microphone unit MUal~
niυan, MUbl〜Mυbta, MUclNMυ
As for the weighting of the sensitivity of each cm, an appropriate weighting mode is determined depending on what kind of directivity is desired when the microphone is set to have the sharpest directivity. It will be done so that it will be adopted.

It should be noted that the larger the number of microphone units that make up the microphone array, the sharper the directional characteristics can be in the state where the sharpest directional characteristics can be obtained, and the sharper the directional characteristics can be when the directional characteristics are in the broadest state. It goes without saying that the smaller the number of microphones used in the central array area zC, the broader the directional characteristics become.

Now, in the variable directional microphone of the present invention, the manner in which the directional characteristics of the microphone changes is as follows:
A first signal level adjuster VRI that adjusts the signal level of a composite signal (first signal) obtained by adding a signal weighted by an to a coefficient unit Kal~ to an output signal of the first side; A coefficient multiplier Kbl~ is applied to the output signals from all the microphone units MUbl~Mυbm belonging to the square array area zS1.
Kbm weighted signal and second lateral array region 25
All microphone units belonging to 2 MUcl = MU
A signal (third signal) obtained by weighting the output signal from c+a with a coefficient unit Kc1·~Keg, and a coefficient unit Kdl~ a second signal level adjuster VR2 that adjusts the signal level of the signal (fourth signal) obtained by adding the composite signal (signal of man 2) obtained by adding the signals weighted by Kdn; It is determined by the manner in which the ratio of the first signal to the fourth signal changes.

(A), (B), and (C) in FIG. 4 show the difference between the first signal and the fourth signal due to the adjustment of the first signal level adjuster VRI and the adjustment of the second signal level adjuster VR2. For example, in the case where the change in the signal level of 1.1 is carried out in the manner shown in FIG. Second signal level regulator VRI
, V112 is a diagram showing the gain of the output signal obtained from each microphone unit corresponding to the positions of the knobs A11B and C in FIG. 4.

Output signal gain for each microphone unit (
The gain (sensitivity) is indicated by the length of each arrow (the arrows represent the gain (sensitivity) of the output signal obtained from the microphone unit, which is the same in Figure 2). ).

In FIG. 3, the horizontal axis is the 1st. The positions of the knobs on the second signal level adjusters VRI and VR2 are shown, and the vertical axis shows the gain (sensitivity) of the output signal of the microphone array.
(This point also applies to FIGS. 7 to 9).

In FIG. 3, 1. Second signal level regulator VRI
, VR2, the knob is set at position A, the first signal is given to the adder ADD from the first signal level adjuster VRI, which is set to the gain l state, and the knob is set to position A. The position of A and the state M
4-, the fourth signal is input to the adder A by the second signal level regulator VR2 whose gain is set to zero.
Therefore, in the variable directional microphone of the present invention when the knob is in the A position, as shown in FIG. Only the output signal of the microphone unit in the array area zC is sent to the output terminal O, and the microphone in this state has the broadest directivity characteristic.

Next, in FIG. In the state where the knobs of the second signal level adjusters VRI and VR2 are at the C position, the 7th position, 1. The gain of the first signal by the first signal level adjuster VRI and the gain of the fourth signal by the second signal level adjuster VR2 are made the same, and in this state, the variable directional microphone of the present invention , the output signals from all the microphone units in the microphone array MA are sent to the output terminal O, and the microphones are made to have the sharpest directional characteristics.

Also, 1st. Second signal level adjuster VRI, VH2
In the state where the knob is located at the mouth position in FIG. 3, the first signal level ammeter VRI
the gain of the first signal by and the second signal level adjuster V
The gain of the fourth signal due to R2 is the gain of the first signal. The positions of the knobs of the second signal level adjusters VRI and VH2 are
The variable directional microphone of the present invention is placed in a state intermediate between the two states described above for positions A and C in the figure, and in this state, the variable directional microphone of the present invention is able to absorb the signals from all the microphone units in its microphone array 1A. The output signal is sent to the output terminal O, and the microphone is placed in a state intermediate between a state in which its directional characteristics are the broadest and a state in which its directional characteristics are the sharpest.

(A) and (B) in FIG. 4, which show how the sensitivity of each microphone unit of the microphone array changes when the directional characteristic of the variable directional microphone of the present invention changes.
In (c), even if the directional characteristics of the microphone are changed,
The sum of the sensitivities of each microphone unit of the microphone array to a sound source far in front of the microphone, which is given to the microphone as the m number of the in-phase and the same level, is kept approximately constant (the directional characteristics of the microphones are different from each other). In (a), (b), and (c) of FIG. 4, which show different states, the arrows for each time are illustrated assuming that the sum of the lengths of the arrows for each time is approximately constant. (This expresses the state in which the sum of the sensitivities of each microphone unit in the microphone array to sound sources far in front of the microphone remains approximately constant even if the microphone's directivity characteristics are changed.)
.

Then, even if the directivity characteristics are changed, the first.
When the ratio between the first signal and the fourth signal is changed by the second signal level illiMWVRIVR2, the sensitivity to the target sound source changes even when the directional characteristics are changed. Since there is nothing to do, it is convenient for collecting sound for broadcasts etc.

In FIG. 5, a cardioid unidirectional microphone array is used, the number of microphone units belonging to the central array area zC is n=7, and the first side array area zS
The number of microphone units provided in 1 is m = 37,
The number m of microphone units provided in the second side array area ZS2 is 37.

A total of 81 microphone units are arranged in a manner that the microphone unit arrangement is [14,2 first, and the sensitivity of each microphone unit is weighted.

Using a microphone array with a Hamming window as shown in the second figure, even if the directional characteristics are changed as described above, the sum of the sensitivities of each microphone unit of the microphone array to a sound source far in front of the microphone is approximately constant. The first and second signal level at units VR
1. VB2 shows a directional characteristic curve diagram at I KHz of a variable directional microphone configured such that the ratio of the first signal to the fourth signal is changed as shown in Figure 3. FIG. 6 shows a directional characteristic curve diagram at 5Hz of the variable directional microphone having the above-mentioned configuration. In addition, point # in Figure 6! The illustrated curve A shows the characteristic curve of the previously proposed variable directional microphone for comparison with the characteristic curve (solid curve A) of the variable directional microphone of the present invention.

Next, the ftS'1 diagram is the first one. Second signal level adjuster V
1st by RI, VR2. The manner in which the ratio of the fourth signal changes is different from that described with reference to FIG.

The first signal is always kept in a gain state of 1, regardless of the position of the knob of the first signal level adjuster VRI,
The fourth signal has a gain of O when the knob of the second signal level i1m adjuster VR2 is in the A position, and a gain of 1 when the knob of the second signal level regulator VR2 is in the C position. This figure shows the operation when the variable 1u directional microphone cutter of the present invention is constructed such that the ratio of the first signal to the fourth signal is changed in such a state that the ratio of the first signal to the fourth signal is changed. be.

In the variable directional microphone of the present invention, the gain of the first signal is always constant and only the gain of the i4 signal is changed from 0 until it becomes the same as the gain of the first signal, as shown in FIG. If the directional characteristics are changed by
The sum of the sensitivities of each microphone unit of the microphone array (the sum of the lengths of the arrows) to a sound source far in front of the microphone gradually increases as the state of the directional pattern changes from a state with a broad directional pattern to a state with a sharp directional pattern. For example, if the directional characteristic of a variable directional microphone is changed from a broad state to a sharp state in accordance with the zooming of an image by a television camera, the sound will also be zoomed in accordance with the zooming of the image. This is effective because the sound is recorded and recorded as if it were in a similar state.

In order to further emphasize the zooming effect explained in connection with FIG. 7, FIG. 8 shows that the first signal and the second This figure shows an example in which both the signal and the signal are gradually increased.

FIG. 9(a) is a block diagram of another configuration aspect of the variable directional microphone of the present invention.
Components similar to those shown in FIG. 1 are not illustrated. In the embodiment shown in FIG. 9(a), the output signal from the adder ADDc is applied to the adder OD, and the output signal from the adder ADD is applied via the signal level adjuster VRo. The signal is sent to output terminal 0.

(b), (c), and (d) in Figure 9 are the 91st! J's (a
) shows the signal level iF[I state of the signal level a by the rectifiers VR2 and VRo, as shown in FIG. 9(b)
is the same as in the case of Fig. 3 already mentioned, (c) in Fig. 9 is the same as in the case of Fig. 7 already mentioned, and (d) in Fig. 9 is the same as in the case of Fig. 3 already mentioned. This is the same as in Figure 8.

(Effects) As is clear from the above detailed explanation in t1, the variable directional microphone of the present invention has a microphone array formed by arranging a plurality of microphone units in a desired arrangement. By setting a central array area of microphone units that includes at least three microphone units, and by arranging a plurality of microphone units arranged on one side of the central array area of microphone units described above, Means for setting a first lateral array area and setting a second lateral array area for microphone units by arranging a plurality of microphone units arranged on the other side of the central array area for the microphone units. and a means for obtaining a first signal obtained by combining the output signals from each microphone unit belonging to the central arrangement area of the microphone unit with predetermined weighting, and the first signal described above. Separately, a second signal obtained by combining the output signals from each microphone unit belonging to the central arrangement area of the microphone unit described above with predetermined weighting, and a first signal from the microphone unit. means for obtaining a j84 signal by synthesizing the output signals from the microphone units disposed in the second side array region with a third signal obtained by synthesizing each with predetermined weighting; ,
Signal ratio changing means for changing the ratio of the first signal to the fourth signal, and in a state where only the first signal is used as an output signal from the directional microphone. , the directional characteristic obtained in a state where the directional microphone has a predetermined first directional characteristic and the ratio of the above-mentioned first Iro and the above-mentioned fourth signal is 1. , a predetermined second
a variable directional microphone with a small number of means for weighting each microphone unit constituting the microphone array so as to have a directional characteristic of Regarding the microphone array arranged in the same manner, a central arrangement area of microphone units including at least three microphone units in the central part of the microphone array is set, and a central arrangement area of the microphone units is set on one side of the central arrangement area of the microphone units. By arranging the plurality of microphone units arranged in the array, a first lateral arrangement region of microphone units is set, and a plurality of microphone units arranged on the other side of the central arrangement region of the microphone units are set. The means for setting the second side array area of microphone units and the output signals from each microphone unit belonging to the central array area of microphone units are synthesized with respective predetermined weights applied. means for obtaining a first signal;
Separately from the first signal described above, a second signal obtained by combining the output signals from each microphone unit belonging to the central array area of the microphone unit with predetermined weighting, respectively; 1st by microphone unit. means for obtaining a fourth signal obtained by synthesizing output signals from microphone units belonging to the second side arrangement region with a third signal obtained by synthesizing the respective output signals with predetermined weighting applied thereto; , signal ratio changing means for changing the ratio of the first signal to the fourth signal, and a state in which only the first signal is used as an output signal from the directional microphone. , the directional characteristics obtained when the directional microphone has a predetermined first directional characteristic and the ratio of the first signal to the fourth signal is 1. and means for weighting each microphone unit forming the microphone array so as to have a predetermined second directivity characteristic. The first signal and the fourth signal are arranged such that the output signal generated based on the distant sound source in front remains approximately constant even if the ratio between the first signal and the fourth signal is changed. Regarding a variable directional microphone provided with a means for changing the signal level of a signal, and a microphone array formed by arranging a plurality of microphone units in a desired arrangement, at least three microphone units in the center of the microphone array. A first lateral arrangement of microphone units is established by setting a central array area of microphone units that includes a central array area of microphone units, and by arranging a plurality of microphone units arranged on one side of the central array area of microphone units described above. a means for setting a second lateral array area of microphone units by arranging a plurality of microphone units arranged on the other side of the central array area of the microphone units; means for obtaining a first signal obtained by combining the output signals from each microphone unit belonging to the central arrangement area of the microphone unit with predetermined weighting, and separately from the above-mentioned first signal; A second signal obtained by combining the output signals from each microphone unit belonging to the central arrangement area of the microphone unit with predetermined weighting applied to each, and a first signal from the microphone unit. means for obtaining a fourth signal obtained by synthesizing output signals from microphone units belonging to the second side arrangement region with a third signal obtained by synthesizing the respective output signals with predetermined weighting applied thereto; , a signal ratio changing means for changing the ratio of the first signal to the fourth signal, and only the first signal is used as an output signal from the directional microphone. Directivity obtained in a state where the directional microphone has a predetermined first directivity characteristic and the ratio of the first signal to the fourth signal is 1. A variable directional microphone comprising means for weighting each microphone unit forming a microphone array so that the characteristic becomes a predetermined second directional characteristic. , when the ratio between the first signal and the fourth signal is changed so that the directional characteristics of the microphone gradually change from a broad state to a sharp state, the above change in signal ratio and Correspondingly, a variable directional microphone comprising means for changing the signal levels of the first signal and the fourth signal so that the output signal generated based on the distant sound source in front is gradually increased. Therefore, according to the variable directional microphone of the present invention, a microphone array having sharp directional characteristics is used, and a central array region, a tenth side array region, and a second side array region are set therein. It is possible to change the directional characteristics of the output signals from the microphone units belonging to each of the above-mentioned regions widely and narrowly using a simple signal processing circuit, and it is also possible to change the directional characteristics between wide and narrow directional characteristics. According to the present invention, the problems of the conventional method can be easily solved satisfactorily.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the variable directional microphone of the present invention, FIGS. 2 and 10 are diagrams showing examples of weighting for microphone units of a microphone array, and FIG.
Figures 7 and 8 and Figures 9 (b) to (d) are shown in Figure 1. The first by the second signal level adjuster. FIG. 4 is an explanatory diagram of how the second signal changes, FIG. 4 is an explanatory diagram of the state of sensitivity of the microphone unit in the microphone array, FIGS. 5 and 6, and FIG. 111! ! ! 9(a) to 9(d) are side views of the directional characteristic curve, and FIG. 9(a) is a partial block diagram of another embodiment of the variable directional microphone of the present invention. MUal"MUan, MUbl~MUbm, MUcl~
MUcm-Microphone array 1-1MA...Microphone array. Knl~nian, Kbl''Kbm, Kcm, Kdl~K
dn-coefficient device, ADDc. ADDt, ADD...adder, VRI, VB2...
1st. Second signal level adjuster, VRo... Signal level adjuster, zC... Central array area, 251...
1st lateral arrangement region, 252... 2nd lateral arrangement region. , ¥) 10 mouths ((L) 'JJ+1 mouth

Claims (1)

[Scope of Claims] 1. Regarding a microphone array formed by arranging a plurality of microphone units in a desired arrangement, a central arrangement area of microphone units including at least three microphone units in the central part of the microphone array is provided. In addition, by arranging a plurality of microphone units arranged on one side of the central array area of the microphone units described above, a first lateral array area of the microphone units is set, and a first lateral array area of the microphone units is set. means for setting a second lateral array area of microphone units by arranging a plurality of microphone units arranged on the other side of the central array area; means for obtaining a first signal which is synthesized by applying a predetermined weight to the output signals of the respective microphone units; A second signal obtained by combining the output signals of the microphone units with predetermined weighting applied thereto, and output signals from the microphone units belonging to the first and second side array regions of the microphone units, respectively. Means for obtaining a fourth signal obtained by combining a third signal obtained by combining with a predetermined weighting, and a ratio between the first signal and the fourth signal. a signal ratio changing means for changing the signal ratio; and a means for changing the signal ratio so that the directional microphone has a predetermined first directional characteristic when only the first signal is used as an output signal from the directional microphone. and the microphone array is arranged so that the directional characteristic obtained when the ratio of the first signal and the fourth signal is 1 becomes a predetermined second directional characteristic. A variable directional microphone 2 comprising means for weighting each microphone unit constituting the microphone, and a microphone array comprising a plurality of microphone units arranged in a desired arrangement. A central array area of microphone units is set that includes at least three microphone units at the center of the array, and a plurality of microphone units are arranged on one side of the central array area of the microphone units. In this way, a first lateral arrangement area of microphone units is set, and a second lateral arrangement area of microphone units is set by arranging a plurality of microphone units arranged on the other side of the central arrangement area of microphone units. means for setting an array area; means for obtaining a first signal obtained by combining the output signals from each microphone unit belonging to the central array area by applying predetermined weights to each of the output signals of the microphone units; Separately from the first signal, a second signal obtained by combining the output signals from each microphone unit belonging to the central array area of the microphone unit with predetermined weighting, and a second signal obtained from the microphone unit. A fourth signal obtained by combining the output signals from the microphone units belonging to the first and second side array areas with a third signal obtained by combining the output signals with predetermined weighting applied to each of them. a signal ratio changing means for changing the ratio of the first signal to the fourth signal; and a signal ratio changing means for changing the ratio of the first signal to the fourth signal; In the state in which the directional microphone is used, the directional microphone has the predetermined first directional characteristic and the first directional characteristic described above.
for each microphone unit constituting the microphone array so that the directional characteristic obtained when the ratio of the signal and the fourth signal is 1 becomes a predetermined second directional characteristic. in a variable directional microphone comprising means for applying weighting, even if the ratio of the first signal to the fourth signal is changed, the weighting is applied based on a distant sound source in front of the microphone. A variable directional microphone 3 provided with means for changing the signal levels of the first signal and the fourth signal so that the output signal is kept approximately constant; a plurality of microphone units arranged in a desired manner; For a microphone array arranged in By the arrangement of the plurality of microphone units, a first side arrangement area of the microphone units is set, and the arrangement of the plurality of microphone units arranged on the other side of the central arrangement area of the microphone units is set. means for setting the second lateral arrangement area of microphone units, and a second lateral arrangement area in which the output signals from each microphone unit belonging to the central arrangement area of microphone units are combined with predetermined weighting, respectively. means for obtaining the first signal, and a means for synthesizing the output signals from each of the microphone units belonging to the central arrangement area of the microphone unit, with predetermined weighting applied to each, separately from the first signal described above. A third signal obtained by combining the obtained second signal and the output signals from the microphone units belonging to the first and second side arrangement regions of the microphone units with predetermined weighting applied to each of them. means for obtaining a fourth signal by combining said first signal and said fourth signal; signal ratio changing means for changing the ratio of said first signal and said fourth signal; and said first signal. is used as the output signal from the directional microphone, the directional microphone has a predetermined first directivity characteristic, and the first signal and the fourth signal are combined. Each microphone unit constituting the microphone array is weighted so that the directional characteristic obtained when the ratio is 1 becomes a predetermined second directional characteristic. In the variable directional microphone, the ratio of the first signal to the fourth signal is changed so that the directional characteristic of the microphone gradually changes from a broad state to a sharp state. When the signal ratio changes, the output signal generated based on the distant sound source in front is gradually increased.
A variable directional microphone 4 is provided with means for changing the signal level of the first signal and the fourth signal, and the ratio of the first signal to the fourth signal is adjusted so that the directional characteristic of the microphone gradually changes from a broad state to a sharp state. is changed, the signal level of the first signal is such that, corresponding to the change in the signal ratio, the output signal resulting from the distant sound source in front is gradually increased. The variable directional microphone according to claim 3, which uses means for changing only the signal level of the fourth signal without giving any change.