JPS58151796A - Microphone - Google Patents

Abstract

PURPOSE:To collect objective sound with good S/N, by arranging plural microphone units in circular arc by taking a point as a center and summing the output of the units. CONSTITUTION:A plurality (2N+1) of microphone units Mic1-MicN are arranged in circular arc by taking a focus F as a center, the outputs of the units Mic1-MicN are summed at an adder SIGMA1 and a synthesized output is extracted from the adder SIGMA1. When a sound source is placed at the focus F, since the distance between the sound source and the units Mic1-MicN is l0, the synthesized output of the adder SIGMA1 is (2N+1) times the output of one microphone unit. When the sound source is placed at a point other than the focus F, the sound at points other than the F is cancelled with each other because of the phase difference and reduced. Then, even if a noise source exists between the focus F and the microphone units, the sound at the focus F apart from the sound source is collected excellently.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microphone device that can pick up a target sound with good S/N ratio from a far away position.
The purpose is to provide a microphone device that can pick up a target sound with a S/N ratio even if there is a noise source between the target sound and a microphone unit.

Generally, in a microphone device, a method of sharpening the directivity of the microphone device itself has been used as a means for collecting a target sound with a high S/N ratio from a far away position. However, there are noise sources (
noise source), and in that case, the target sound is
I couldn't capture the sound well.

The present invention solves these conventional drawbacks,
A plurality of microphone units are arranged in an arc shape with one point as the center, and the outputs of these microphone units are added and extracted. According to this configuration, the center point of the plurality of microphone units arranged in an arc shape can be set as a focal point, and only the sound of this focal point can be collected, thereby making it possible to connect the microphone unit and the target sound (at the focal position). It has the advantage that even if there is a noise source between the sound and the target sound, the target sound can be picked up at a S/N ratio.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The microphone device of the present invention will be described below with reference to drawings of embodiments.

FIG. 1 shows an embodiment of the microphone device of the present invention. In FIG. 1, a plurality of (2N+1) microphone units MICI, MiC2, MiCs-.
... Arranged in an arc shape with MiCN as the center of the focal point F, these microphone devices) MiCl, Mi02
.

The outputs of MiCs...MiCN are added together by an adder Σ1, and a combined output is taken out from the adder Σ1. In such a configuration, if we assume that there is a sound source at the focal point F, the sound source at the focal point F and the microphone units MiC1, MiC2, MiCs-9-...
- Since the distance between MiCNs is Qo, the combined output of adder Σ1 is 2N+1 times the output of one microphone unit. On the other hand, when the sound source is located at a position other than the focal point F, the sound source and each microphone unit MiC1,
Since the distance between MiC2, Mi(53, river...MiCN is different, each microphone unit Mi(jl,
A phase difference occurs in the outputs of MiC2, MiCs...Mi(11), and the combined output of adder Σ1 decreases. Therefore, the sound at the focal point F can be picked up best, and the sound at the focal point F
Sounds other than those canceled out by the phase difference are 0, so
Focal point F and microphone units MiC1, Mtc2,
Even when there is a noise source between MiCs...MiCN, the sound at the focal point F, which is farther away than the noise source, can be picked up well. Here, microphone units MiC1, M
LC2, MiCs...MiCN can produce a focal effect even with omnidirectionality, but by using a directional microphone, it is possible to create a system that does not pick up sound from the back. Sound can be picked up with better S/N.

Specifically, as a system for a frequency of 1000Hz and a focus of 20ocfn, a microphone unit MiC1 is used.
, MiC2, M2O3... River, the distance between MiCN is 20, and the microphone units MiC1, MiC2
゜MiCs...21 unidirectional micropon units were arranged as MiCN. The second characteristic is
As shown in the figure. Here, the horizontal axis indicates the distance on the X axis when the focal length L0 is 1, and since L□=200m, it is 0.
1 indicates the position 20 cm from MiCl. The vertical axis represents the relative value of the output voltage, with each division being 10 dB.

In Fig. 2, a is the output characteristic of the conventional microphone with respect to distance, b is the output characteristic of the microphone of this embodiment, and C is the output characteristic of the microphone of this embodiment when the sound is picked up by the conventional microphone. It is a comparative characteristic. As can be understood from FIG. 2, the output characteristic of the conventional microphone is an inverse square law with respect to distance, and as the distance between the microphone unit and the sound source becomes shorter, the sound becomes louder in inverse proportion to the distance. On the other hand, with the microbon of this embodiment, sound can be picked up best at the focal point position (horizontal axis -1), and it may be difficult to pick up sound both near and far from the focal point F.

FIG. 3 shows another embodiment of the micropon device of the present invention. In FIG. 3, 13 microphone units MicO, MiCl...1lice are connected to the focal point F
They are arranged six on each side around a central axis I that passes through the center, and are arranged in an arc shape around the focal point F. And the above-mentioned Microphone Units) MiCQ.

MiCl °°゛°°MiC4 output is added to adder Σ11
The configuration is such that the combined output of the adder Σ11 is taken out through the bypass filter HPF, and the micropons unit y) MiCO, MiC2, MtC4,
tcs.

The output of MiC6 is added by an adder Σ12, and the combined output of the adder Σ12 is taken out through a low-pass filter LPF.Where: 6 on each side centered on the central axis X passing through the focal point F 13 microphone units MiCO arranged on a circumference centered on the focal point F.

MiCl...MIC6o microphone spacing is microponyu=, )MiCO, MiCl, ML02. Mi
03. The interval of Mi04 is dl, and the microbon unit MiC4.

MzCq, MsOe are 8 times apart,
2d, = d2. In other words, the output of the microphone units MtCo, MiCl...marked, Mic6 color is used as a high frequency band using the high-pass filter HPF after calculating the sum on the microphone interval d1 side, and after calculating the sum on the microphone interval 2d1 side. A low-pass filter LPF is used for use on the low frequency side. In general, the wavelengths in the low and high frequencies are significantly different, so a microphone spacing that shows an excellent focusing effect in the low range has a poor focusing effect in the high range, and vice versa, but as in this example, By having a multi-way configuration, a microphone with good focusing effect over the entire band can be obtained.

Furthermore, since the microphone unit is shared, the number of units can be reduced, and many other effects are achieved.

As described above, according to the present invention, a plurality of microphone units are arranged in an arc shape with one point as the center, and the outputs of the plurality of microphone units are added and extracted. With one point as the focal point, only the sound at this focal point can be collected. Therefore, even if there is a noise source between the microphone unit and the target sound, the target sound can be
It has the advantage of being able to pick up sounds.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the microphone device of the present invention, FIG. 2 is a diagram showing the output characteristics of the same device, and FIG. 3 is a block diagram showing another embodiment of the microphone device of the present invention. yico, 1lic1. mic2------M
ICN---Microphone unit, Σ1. Σ1
1. Σ12...Adder, HPF...Bypass filter, LPF...Low pass filter,
F...Focus. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 [LO] Figure 3

Claims (1)

[Scope of Claims] (1) A microphone device configured such that a plurality of microphone units are arranged in an arc shape centered at a certain point, and the outputs of the plurality of microphone units are added and extracted. @) The multiple microphone units are divided into several blocks with narrow microphone intervals, and the combined output of the microphone units composing each block is extracted by passing it through an electric filter that divides the frequency band. Claim 1 characterized in that
Microphone device as described in section. (3) The microphone device according to claim 2, wherein the plurality of microphone units are arranged so as to be used in common between blocks into which the frequency band is divided.